data.json

[
  {
    "name": "Object/array literal extensions",
    "target": "es5",
    "significance": "large",
    "subtests": [
      {
        "name": "Getter accessors",
        "exec": "return ({ get x(){ return 1 } }).x === 1;"
      },
      {
        "name": "Setter accessors",
        "exec": "var value = 0;\n({ set x(v){ value = v; } }).x = 1;\nreturn value === 1;"
      },
      {
        "name": "Trailing commas in object literals",
        "exec": "return { a: true, }.a === true;"
      },
      {
        "name": "Trailing commas in array literals",
        "exec": "return [1,].length === 1;"
      },
      {
        "name": "Reserved words as property names",
        "exec": "return ({ if: 1 }).if === 1;"
      }
    ]
  },
  {
    "name": "Object static methods",
    "target": "es5",
    "significance": "large",
    "subtests": [
      {
        "name": "Object.create",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create",
        "exec": "function () {\nreturn typeof Object.create === 'function';\n    }"
      },
      {
        "name": "Object.defineProperty",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty",
        "exec": "function () {\nreturn typeof Object.defineProperty === 'function';\n    }"
      },
      {
        "name": "Object.defineProperties",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperties",
        "exec": "function () {\nreturn typeof Object.defineProperties === 'function';\n    }"
      },
      {
        "name": "Object.getPrototypeOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getPrototypeOf",
        "exec": "function () {\nreturn typeof Object.getPrototypeOf === 'function';\n    }"
      },
      {
        "name": "Object.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys",
        "exec": "function () {\nreturn typeof Object.keys === 'function';\n    }"
      },
      {
        "name": "Object.seal",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal",
        "exec": "function () {\nreturn typeof Object.seal === 'function';\n    }"
      },
      {
        "name": "Object.freeze",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze",
        "exec": "function () {\nreturn typeof Object.freeze === 'function';\n    }"
      },
      {
        "name": "Object.preventExtensions",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/preventExtensions",
        "exec": "function () {\nreturn typeof Object.preventExtensions === 'function';\n    }"
      },
      {
        "name": "Object.isSealed",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed",
        "exec": "function () {\nreturn typeof Object.isSealed === 'function';\n    }"
      },
      {
        "name": "Object.isFrozen",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen",
        "exec": "function () {\nreturn typeof Object.isFrozen === 'function';\n    }"
      },
      {
        "name": "Object.isExtensible",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible",
        "exec": "function () {\nreturn typeof Object.isExtensible === 'function';\n    }"
      },
      {
        "name": "Object.getOwnPropertyDescriptor",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyDescriptor",
        "exec": "function () {\nreturn typeof Object.getOwnPropertyDescriptor === 'function';\n    }"
      },
      {
        "name": "Object.getOwnPropertyNames",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames",
        "exec": "function () {\nreturn typeof Object.getOwnPropertyNames === 'function';\n    }"
      }
    ]
  },
  {
    "name": "Array methods",
    "target": "es5",
    "significance": "large",
    "subtests": [
      {
        "name": "Array.isArray",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray",
        "exec": "function () {\nreturn typeof Array.isArray === 'function';\n      }"
      },
      {
        "name": "Array.prototype.indexOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf",
        "exec": "function () {\nreturn typeof Array.prototype.indexOf === 'function';\n      }"
      },
      {
        "name": "Array.prototype.lastIndexOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/lastIndexOf",
        "exec": "function () {\nreturn typeof Array.prototype.lastIndexOf === 'function';\n      }"
      },
      {
        "name": "Array.prototype.every",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every",
        "exec": "function () {\nreturn typeof Array.prototype.every === 'function';\n      }"
      },
      {
        "name": "Array.prototype.some",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some",
        "exec": "function () {\nreturn typeof Array.prototype.some === 'function';\n      }"
      },
      {
        "name": "Array.prototype.forEach",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach",
        "exec": "function () {\nreturn typeof Array.prototype.forEach === 'function';\n      }"
      },
      {
        "name": "Array.prototype.map",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map",
        "exec": "function () {\nreturn typeof Array.prototype.map === 'function';\n      }"
      },
      {
        "name": "Array.prototype.filter",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter",
        "exec": "function () {\nreturn typeof Array.prototype.filter === 'function';\n      }"
      },
      {
        "name": "Array.prototype.reduce",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce",
        "exec": "function () {\nreturn typeof Array.prototype.reduce === 'function';\n      }"
      },
      {
        "name": "Array.prototype.reduceRight",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduceRight",
        "exec": "function () {\nreturn typeof Array.prototype.reduceRight === 'function';\n      }"
      },
      {
        "name": "Array.prototype.sort: compareFn must be function or undefined",
        "exec": "function () {\ntry {\n  [1,2].sort(null);\n  return false;\n} catch (enull) {}\ntry {\n  [1,2].sort(true);\n  return false;\n} catch (etrue) {}\ntry {\n  [1,2].sort({});\n  return false;\n} catch (eobj) {}\ntry {\n  [1,2].sort([]);\n  return false;\n} catch (earr) {}\ntry {\n  [1,2].sort(/a/g);\n  return false;\n} catch (eregex) {}\nreturn true;\n      }"
      },
      {
        "name": "Array.prototype.sort: compareFn may be explicit undefined",
        "exec": "function () {\ntry {\n  var arr = [2, 1];\n  return arr.sort(undefined) === arr && arr[0] === 1 && arr[1] === 2;\n} catch (e) {\n  return false;\n}\n      }"
      },
      {
        "name": "Array.prototype.unshift: [].unshift(0) returns the unshifted count",
        "exec": "function () {\nreturn [].unshift(0) === 1;\n      }"
      }
    ]
  },
  {
    "name": "String properties and methods",
    "target": "es5",
    "significance": "small",
    "subtests": [
      {
        "name": "Property access on strings",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String#Character_access",
        "exec": "function () {\nreturn \"foobar\"[3] === \"b\";\n    }"
      },
      {
        "name": "String.prototype.split",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split",
        "exec": "function () {\n// all of these tests reflect bugs that es5-shim patches\nreturn typeof String.prototype.split === 'function'\n  && ''.split().length === 1 && ''.split()[0] === ''\n  && ''.split(undefined).length === 1 && ''.split(undefined)[0] === ''\n  && 'ab'.split().length === 1 && 'ab'.split()[0] === 'ab'\n  && 'ab'.split(undefined).length === 1 && 'ab'.split(undefined)[0] === 'ab'\n  && '0'.split(undefined, 0).length === 0\n  && 'ab'.split(/(?:ab)*/).length === 2\n  && '.'.split(/(.?)(.?)/).length === 4\n  && 'tesst'.split(/(s)*/)[1] !== 't'\n  && 'test'.split(/(?:)/, -1).length === 4\n  && ''.split(/.?/).length === 0\n  && '.'.split(/()()/).length === 1;\n    }"
      },
      {
        "name": "String.prototype.substr",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr",
        "exec": "function () {\nreturn '0b'.substr(-1) === 'b';\n    }"
      },
      {
        "name": "String.prototype.trim",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/Trim",
        "exec": "function () {\nreturn typeof String.prototype.trim === 'function';\n    }"
      }
    ]
  },
  {
    "name": "Date methods",
    "target": "es5",
    "significance": "small",
    "subtests": [
      {
        "name": "Date.prototype.toISOString",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString",
        "exec": "function () {\nreturn typeof Date.prototype.toISOString === 'function';\n    }"
      },
      {
        "name": "Date.now",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now",
        "exec": "function () {\nreturn typeof Date.now === 'function';\n    }"
      },
      {
        "name": "Date.prototype.toJSON",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toJSON",
        "exec": "function () {\ntry {\n  return Date.prototype.toJSON.call(new Date(NaN)) === null;\n} catch (e) {\n  return false;\n}\n    }"
      }
    ]
  },
  {
    "name": "Function.prototype.bind",
    "target": "es5",
    "significance": "medium",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind",
    "exec": "function () {\nreturn typeof Function.prototype.bind === 'function';\n  }"
  },
  {
    "name": "JSON",
    "target": "es5",
    "significance": "medium",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON",
    "exec": "function () {\nreturn typeof JSON === 'object';\n  }"
  },
  {
    "name": "Immutable globals",
    "target": "es5",
    "significance": "small",
    "subtests": [
      {
        "name": "undefined",
        "exec": "undefined = 12345;\nvar result = typeof undefined === 'undefined';\nundefined = void 0;\nreturn result;"
      },
      {
        "name": "NaN",
        "exec": "NaN = false;\nvar result = typeof NaN === 'number';\nNaN = Math.sqrt(-1);\nreturn result;"
      },
      {
        "name": "Infinity",
        "exec": "Infinity = false;\nvar result = typeof Infinity === 'number';\nInfinity = 1/0;\nreturn result;"
      }
    ]
  },
  {
    "name": "Number methods",
    "target": "es5",
    "significance": "small",
    "subtests": [
      {
        "name": "Number.prototype.toExponential rounds properly",
        "exec": "function () {\nreturn (-6.9e-11).toExponential(4) === '-6.9000e-11' // Edge <= 17\n  && (25).toExponential(0) === '3e+1' // FF <= 86\n  && (1.255).toExponential(2) === '1.25e+0'; // IE <= 11 && Edge <= 14\n    }"
      },
      {
        "name": "Number.prototype.toExponential throws on ±Infinity fractionDigits",
        "exec": "function () {\ntry {\n  (1).toExponential(Infinity);\n  (1).toExponential(-Infinity);\n  return false;\n} catch (e) {\n  return true;\n}\n    }"
      },
      {
        "name": "Number.prototype.toExponential does not throw on edge cases",
        "exec": "function () {\ntry {\n  NaN.toExponential(Infinity);\n  Infinity.toExponential(Infinity);\n  return true;\n} catch (e) {\n  return false;\n}\n    }"
      }
    ]
  },
  {
    "name": "Miscellaneous",
    "target": "es5",
    "significance": "medium",
    "subtests": [
      {
        "name": "Function.prototype.apply permits array-likes",
        "exec": "function () {\ntry {\n  return (function(a,b) { return a === 1 && b === 2; }).apply({}, {0:1, 1:2, length:2});\n} catch (e) {\n  return false;\n}\n    }"
      },
      {
        "name": "parseInt ignores leading zeros",
        "exec": "function () {\nreturn parseInt('010') === 10;\n    }"
      },
      {
        "name": "Function \"prototype\" property is non-enumerable",
        "exec": "return !Function().propertyIsEnumerable('prototype');"
      },
      {
        "name": "Arguments toStringTag is \"Arguments\"",
        "exec": "return (function(){ return Object.prototype.toString.call(arguments) === '[object Arguments]'; }());"
      },
      {
        "name": "Zero-width chars in identifiers",
        "exec": "var _\\u200c\\u200d = true;\nreturn _\\u200c\\u200d;"
      },
      {
        "name": "Unreserved words",
        "exec": "var abstract, boolean, byte, char, double, final, float, goto, int, long,\n  native, short, synchronized, transient, volatile;\nreturn true;"
      },
      {
        "name": "Enumerable properties can be shadowed by non-enumerables",
        "exec": "var result = true;\nObject.prototype.length = 42;\nfor (var i in Function) {\n    if (i === 'length') {\n        result = false;\n    }\n}\ndelete Object.prototype.length;\nreturn result;"
      },
      {
        "name": "Thrown functions have proper \"this\" values",
        "exec": "try {\n  throw function() { return !('a' in this); };\n}\ncatch(e) {\n  var a = true;\n  return e();\n}"
      }
    ]
  },
  {
    "name": "Strict mode",
    "target": "es5",
    "significance": "large",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode",
    "subtests": [
      {
        "name": "reserved words",
        "exec": "'use strict';\nvar words = 'implements,interface,let,package,private,protected,public,static,yield'.split(',');\nfor (var i = 0; i < 9; i+=1) {\n  try { eval('var ' + words[i]); return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\n}\nreturn true;"
      },
      {
        "name": "\"this\" is undefined in functions",
        "exec": "'use strict';\nreturn this === void undefined && (function(){ return this === void undefined; }).call();"
      },
      {
        "name": "\"this\" is not coerced to object in primitive methods",
        "exec": "'use strict';\nreturn (function(){ return typeof this === 'string' }).call('')\n  && (function(){ return typeof this === 'number' }).call(1)\n  && (function(){ return typeof this === 'boolean' }).call(true);"
      },
      {
        "name": "\"this\" is not coerced to object in primitive accessors",
        "exec": "'use strict';\n\nfunction test(Class, instance) {\n  Object.defineProperty(Class.prototype, 'test', {\n    get: function () { passed = passed && this === instance; },\n    set: function () { passed = passed && this === instance; },\n    configurable: true\n  });\n\n  var passed = true;\n  instance.test;\n  instance.test = 42;\n  return passed;\n}\n\nreturn test(String, '')\n  && test(Number, 1)\n  && test(Boolean, true);"
      },
      {
        "name": "legacy octal is a SyntaxError",
        "exec": "'use strict';\ntry { eval('010');     return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('\"\\\\010\"'); return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\nreturn true;"
      },
      {
        "name": "assignment to unresolvable identifiers is a ReferenceError",
        "exec": "'use strict';\ntry { eval('__i_dont_exist = 1'); } catch (err) { return err instanceof ReferenceError; }"
      },
      {
        "name": "assignment to eval or arguments is a SyntaxError",
        "exec": "'use strict';\ntry { eval('eval = 1');      return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('arguments = 1'); return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('eval++');        return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('arguments++');   return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\nreturn true;"
      },
      {
        "name": "assignment to non-writable properties is a TypeError",
        "exec": "'use strict';\ntry { Object.defineProperty({},\"x\",{ writable: false }).x = 1; return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\ntry { Object.preventExtensions({}).x = 1;                      return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\ntry { ({ get x(){ } }).x = 1;                                  return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\ntry { (function f() { f = 123; })();                           return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\nreturn true;"
      },
      {
        "name": "eval or arguments bindings is a SyntaxError",
        "exec": "'use strict';\ntry { eval('var eval');                return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('var arguments');           return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('(function(eval){})');      return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('(function(arguments){})'); return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('try{}catch(eval){}');      return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\ntry { eval('try{}catch(arguments){}'); return false; } catch (err) { if (!(err instanceof SyntaxError)) return false; }\nreturn true;"
      },
      {
        "name": "arguments.caller removed or is a TypeError",
        "exec": "'use strict';\nif ('caller' in arguments) {\n  try { arguments.caller; return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\n}\nreturn true;"
      },
      {
        "name": "arguments.callee is a TypeError",
        "exec": "'use strict';\ntry { arguments.callee; return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\nreturn true;"
      },
      {
        "name": "(function(){}).caller and (function(){}).arguments is a TypeError",
        "exec": "'use strict';\ntry { (function(){}).caller;    return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\ntry { (function(){}).arguments; return false; } catch (err) { if (!(err instanceof TypeError)) return false; }\nreturn true;"
      },
      {
        "name": "arguments is unmapped",
        "exec": "'use strict';\nreturn (function(x){\n  x = 2;\n  return arguments[0] === 1;\n})(1) && (function(x){\n  arguments[0] = 2;\n  return x === 1;\n})(1);"
      },
      {
        "name": "eval() can't create bindings",
        "exec": "'use strict';\ntry { eval('var __some_unique_variable;'); __some_unique_variable; } catch (err) { return err instanceof ReferenceError; }"
      },
      {
        "name": "deleting bindings is a SyntaxError",
        "exec": "'use strict';\ntry { eval('var x; delete x;'); } catch (err) { return err instanceof SyntaxError; }"
      },
      {
        "name": "deleting non-configurable properties is a TypeError",
        "exec": "'use strict';\ntry { delete Object.prototype; } catch (err) { return err instanceof TypeError; }"
      },
      {
        "name": "\"with\" is a SyntaxError",
        "exec": "'use strict';\ntry { eval('with({}){}'); } catch (err) { return err instanceof SyntaxError; }"
      },
      {
        "name": "repeated parameter names is a SyntaxError",
        "exec": "'use strict';\ntry { eval('function f(x, x) { }'); } catch (err) { return err instanceof SyntaxError; }"
      },
      {
        "name": "function expressions with matching name and argument are valid",
        "exec": "var foo = function bar(bar) {'use strict'};\nreturn typeof foo === 'function';"
      }
    ]
  },
  {
    "name": "proper tail calls (tail call optimisation)",
    "target": "es6",
    "category": "optimisation",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-tail-position-calls",
    "subtests": [
      {
        "name": "direct recursion",
        "exec": "\"use strict\";\nreturn (function f(n){\n  if (n <= 0) {\n    return  \"foo\";\n  }\n  return f(n - 1);\n}(1e6)) === \"foo\";"
      },
      {
        "name": "mutual recursion",
        "exec": "\"use strict\";\nfunction f(n){\n  if (n <= 0) {\n    return  \"foo\";\n  }\n  return g(n - 1);\n}\nfunction g(n){\n  if (n <= 0) {\n    return  \"bar\";\n  }\n  return f(n - 1);\n}\nreturn f(1e6) === \"foo\" && f(1e6+1) === \"bar\";"
      }
    ]
  },
  {
    "name": "default function parameters",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-functiondeclarationinstantiation",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "return (function (a = 1, b = 2) { return a === 3 && b === 2; }(3));"
      },
      {
        "name": "explicit undefined defers to the default",
        "exec": "return (function (a = 1, b = 2) { return a === 1 && b === 3; }(undefined, 3));"
      },
      {
        "name": "defaults can refer to previous params",
        "exec": "return (function (a, b = a) { return b === 5; }(5));"
      },
      {
        "name": "arguments object interaction",
        "exec": "return (function (a = \"baz\", b = \"qux\", c = \"quux\") {\n  a = \"corge\";\n  // The arguments object is not mapped to the\n  // parameters, even outside of strict mode.\n  return arguments.length === 2\n    && arguments[0] === \"foo\"\n    && arguments[1] === \"bar\";\n}(\"foo\", \"bar\"));"
      },
      {
        "name": "temporal dead zone",
        "exec": "return (function(x = 1) {\n  try {\n    eval(\"(function(a=a){}())\");\n    return false;\n  } catch(e) {}\n  try {\n    eval(\"(function(a=b,b){}())\");\n    return false;\n  } catch(e) {}\n  return true;\n}());"
      },
      {
        "name": "separate scope",
        "exec": "return (function(a=function(){\n  return typeof b === 'undefined';\n}){\n  var b = 1;\n  return a();\n}());"
      },
      {
        "name": "new Function() support",
        "exec": "return new Function(\"a = 1\", \"b = 2\",\n  \"return a === 3 && b === 2;\"\n)(3);"
      }
    ]
  },
  {
    "name": "rest parameters",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-function-definitions",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "return (function (foo, ...args) {\n  return args instanceof Array && args + \"\" === \"bar,baz\";\n}(\"foo\", \"bar\", \"baz\"));"
      },
      {
        "name": "function 'length' property",
        "exec": "return function(a, ...b){}.length === 1 && function(...c){}.length === 0;"
      },
      {
        "name": "arguments object interaction",
        "exec": "return (function (foo, ...args) {\n  foo = \"qux\";\n  // The arguments object is not mapped to the\n  // parameters, even outside of strict mode.\n  return arguments.length === 3\n    && arguments[0] === \"foo\"\n    && arguments[1] === \"bar\"\n    && arguments[2] === \"baz\";\n}(\"foo\", \"bar\", \"baz\"));"
      },
      {
        "name": "can't be used in setters",
        "exec": "return (function (...args) {\n  try {\n    eval(\"({set e(...args){}})\");\n  } catch(e) {\n    return true;\n  }\n}());"
      },
      {
        "name": "new Function() support",
        "exec": "return new Function(\"a\", \"...b\",\n  \"return b instanceof Array && a+b === 'foobar,baz';\"\n)('foo','bar','baz');"
      }
    ]
  },
  {
    "name": "spread syntax for iterable objects",
    "target": "es6",
    "category": "syntax",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-argument-lists-runtime-semantics-argumentlistevaluation",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator",
    "subtests": [
      {
        "name": "with arrays, in function calls",
        "exec": "return Math.max(...[1, 2, 3]) === 3"
      },
      {
        "name": "with arrays, in array literals",
        "exec": "return [...[1, 2, 3]][2] === 3;"
      },
      {
        "name": "with sparse arrays, in function calls",
        "exec": "var a = Array(...[,,]);\nreturn \"0\" in a && \"1\" in a && '' + a[0] + a[1] === \"undefinedundefined\";"
      },
      {
        "name": "with sparse arrays, in array literals",
        "exec": "var a = [...[,,]];\nreturn \"0\" in a && \"1\" in a && '' + a[0] + a[1] === \"undefinedundefined\";"
      },
      {
        "name": "with strings, in function calls",
        "exec": "return Math.max(...\"1234\") === 4;"
      },
      {
        "name": "with strings, in array literals",
        "exec": "return [\"a\", ...\"bcd\", \"e\"][3] === \"d\";"
      },
      {
        "name": "with astral plane strings, in function calls",
        "exec": "return Array(...\"𠮷𠮶\")[0] === \"𠮷\";"
      },
      {
        "name": "with astral plane strings, in array literals",
        "exec": "return [...\"𠮷𠮶\"][0] === \"𠮷\";"
      },
      {
        "name": "with generator instances, in calls",
        "exec": "var iterable = (function*(){ yield 1; yield 2; yield 3; }());\nreturn Math.max(...iterable) === 3;"
      },
      {
        "name": "with generator instances, in arrays",
        "exec": "var iterable = (function*(){ yield \"b\"; yield \"c\"; yield \"d\"; }());\nreturn [\"a\", ...iterable, \"e\"][3] === \"d\";"
      },
      {
        "name": "with generic iterables, in calls",
        "exec": "var iterable = global.__createIterableObject([1, 2, 3]);\nreturn Math.max(...iterable) === 3;"
      },
      {
        "name": "with generic iterables, in arrays",
        "exec": "var iterable = global.__createIterableObject([\"b\", \"c\", \"d\"]);\nreturn [\"a\", ...iterable, \"e\"][3] === \"d\";"
      },
      {
        "name": "with instances of iterables, in calls",
        "exec": "var iterable = global.__createIterableObject([1, 2, 3]);\nreturn Math.max(...Object.create(iterable)) === 3;"
      },
      {
        "name": "with instances of iterables, in arrays",
        "exec": "var iterable = global.__createIterableObject([\"b\", \"c\", \"d\"]);\nreturn [\"a\", ...Object.create(iterable), \"e\"][3] === \"d\";"
      },
      {
        "name": "spreading non-iterables is a runtime error",
        "exec": "try {\n  Math.max(...2);\n} catch(e) {\n  return Math.max(...[1, 2, 3]) === 3;\n}"
      }
    ]
  },
  {
    "name": "object literal extensions",
    "target": "es6",
    "category": "syntax",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-object-initialiser",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer#New_notations_in_ECMAScript_2015",
    "subtests": [
      {
        "name": "computed properties",
        "exec": "var x = 'y';\nreturn ({ [x]: 1 }).y === 1;"
      },
      {
        "name": "shorthand properties",
        "exec": "var a = 7, b = 8, c = {a,b};\nreturn c.a === 7 && c.b === 8;"
      },
      {
        "name": "shorthand methods",
        "exec": "return ({ y() { return 2; } }).y() === 2;"
      },
      {
        "name": "string-keyed shorthand methods",
        "exec": "return ({ \"foo bar\"() { return 4; } })[\"foo bar\"]() === 4;"
      },
      {
        "name": "computed shorthand methods",
        "exec": "var x = 'y';\nreturn ({ [x](){ return 1 } }).y() === 1;"
      },
      {
        "name": "computed accessors",
        "exec": "var x = 'y',\n    valueSet,\n    obj = {\n      get [x] () { return 1 },\n      set [x] (value) { valueSet = value }\n    };\nobj.y = 'foo';\nreturn obj.y === 1 && valueSet === 'foo';"
      }
    ]
  },
  {
    "name": "for..of loops",
    "target": "es6",
    "category": "syntax",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-for-in-and-for-of-statements",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of",
    "subtests": [
      {
        "name": "with arrays",
        "exec": "var arr = [5];\nfor (var item of arr)\n  return item === 5;"
      },
      {
        "name": "with sparse arrays",
        "exec": "var arr = [,,];\nvar count = 0;\nfor (var item of arr)\n  count += (item === void undefined);\nreturn count === 2;"
      },
      {
        "name": "with strings",
        "exec": "var str = \"\";\nfor (var item of \"foo\")\n  str += item;\nreturn str === \"foo\";"
      },
      {
        "name": "with astral plane strings",
        "exec": "var str = \"\";\nfor (var item of \"𠮷𠮶\")\n  str += item + \" \";\nreturn str === \"𠮷 𠮶 \";"
      },
      {
        "name": "with generator instances",
        "exec": "var result = \"\";\nvar iterable = (function*(){ yield 1; yield 2; yield 3; }());\nfor (var item of iterable) {\n  result += item;\n}\nreturn result === \"123\";"
      },
      {
        "name": "with generic iterables",
        "exec": "var result = \"\";\nvar iterable = global.__createIterableObject([1, 2, 3]);\nfor (var item of iterable) {\n  result += item;\n}\nreturn result === \"123\";"
      },
      {
        "name": "with instances of generic iterables",
        "exec": "var result = \"\";\nvar iterable = global.__createIterableObject([1, 2, 3]);\nfor (var item of Object.create(iterable)) {\n  result += item;\n}\nreturn result === \"123\";"
      },
      {
        "name": "iterator closing, break",
        "exec": "var closed = false;\nvar iter = __createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\nfor (var it of iter) break;\nreturn closed;"
      },
      {
        "name": "iterator closing, throw",
        "exec": "var closed = false;\nvar iter = __createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\ntry {\n  for (var it of iter) throw 0;\n} catch(e){}\nreturn closed;"
      }
    ]
  },
  {
    "name": "octal and binary literals",
    "target": "es6",
    "category": "syntax",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-literals-numeric-literals",
    "subtests": [
      {
        "name": "octal literals",
        "exec": "return 0o10 === 8 && 0O10 === 8;"
      },
      {
        "name": "binary literals",
        "exec": "return 0b10 === 2 && 0B10 === 2;"
      },
      {
        "name": "octal supported by Number()",
        "exec": "return Number('0o1') === 1;"
      },
      {
        "name": "binary supported by Number()",
        "exec": "return Number('0b1') === 1;"
      }
    ]
  },
  {
    "name": "template literals",
    "target": "es6",
    "category": "syntax",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-template-literals",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var a = \"ba\", b = \"QUX\";\nreturn `foo bar\n${a + \"z\"} ${b.toLowerCase()}` === \"foo bar\\nbaz qux\";"
      },
      {
        "name": "toString conversion",
        "exec": "var a = {\n  toString: function() { return \"foo\"; },\n  valueOf: function() { return \"bar\"; }\n};\nreturn `${a}` === \"foo\";"
      },
      {
        "name": "tagged template literals",
        "exec": "var called = false;\nfunction fn(parts, a, b) {\n  called = true;\n  return parts instanceof Array &&\n    parts[0]     === \"foo\"      &&\n    parts[1]     === \"bar\\n\"    &&\n    parts.raw[0] === \"foo\"      &&\n    parts.raw[1] === \"bar\\\\n\"   &&\n    a === 123                   &&\n    b === 456;\n}\nreturn fn `foo${123}bar\\n${456}` && called;"
      },
      {
        "name": "passed array is frozen",
        "exec": "return (function(parts) {\n  return Object.isFrozen(parts) && Object.isFrozen(parts.raw);\n}) `foo${0}bar${0}baz`;"
      },
      {
        "name": "line break normalisation",
        "exec": "var cr   = eval(\"`x\" + String.fromCharCode(13)    + \"y`\");\nvar lf   = eval(\"`x\" + String.fromCharCode(10)    + \"y`\");\nvar crlf = eval(\"`x\" + String.fromCharCode(13,10) + \"y`\");\n\nreturn cr.length === 3 && lf.length === 3 && crlf.length === 3\n  && cr[1] === lf[1] && lf[1] === crlf[1] && crlf[1] === '\\n';"
      },
      {
        "name": "TemplateStrings call site caching",
        "exec": "// TemplateStrings caching was changed from per-contents to\n// per-call-site.\n// https://github.com/tc39/ecma262/pull/890\nfunction strings(array) {\n  return array;\n}\nfunction getStrings() {\n  return strings`foo`;\n}\nvar original = getStrings();\nvar other = strings`foo`;\nreturn original === getStrings() && original !== other;"
      },
      {
        "name": "TemplateStrings permanent caching",
        "exec": "function strings(array) {\n  return array;\n}\nfunction getStrings() {\n  return strings`foo`;\n}\nvar original = getStrings();\nvar newed = new getStrings();\nreturn original === getStrings() && original === newed;"
      }
    ]
  },
  {
    "name": "RegExp \"y\" and \"u\" flags",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-get-regexp.prototype.sticky",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#Parameters",
    "subtests": [
      {
        "name": "\"y\" flag",
        "exec": "var re = new RegExp('\\\\w', 'y');\nre.exec('xy');\nreturn (re.exec('xy')[0] === 'y');"
      },
      {
        "name": "\"y\" flag, lastIndex",
        "exec": "var re = new RegExp('yy', 'y');\nre.lastIndex = 3;\nvar result = re.exec('xxxyyxx')[0];\nreturn result === 'yy' && re.lastIndex === 5;"
      },
      {
        "name": "\"u\" flag",
        "exec": "return \"𠮷\".match(/^.$/u)[0].length === 2;"
      },
      {
        "name": "\"u\" flag, non-BMP Unicode characters",
        "exec": "return \"𠮷x\".match(/^.x$/u)[0].length === 3;"
      },
      {
        "name": "\"u\" flag, Unicode code point escapes",
        "exec": "return \"𝌆\".match(/\\u{1d306}/u)[0].length === 2;"
      },
      {
        "name": "\"u\" flag, case folding",
        "exec": "return \"ſ\".match(/S/iu) && \"S\".match(/ſ/iu);"
      }
    ]
  },
  {
    "name": "destructuring, declarations",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-destructuring-assignment",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment",
    "subtests": [
      {
        "name": "with arrays",
        "exec": "var [a, , [b], c] = [5, null, [6]];\nreturn a === 5 && b === 6 && c === void undefined;"
      },
      {
        "name": "with sparse arrays",
        "exec": "var [a, , b] = [,,,];\nreturn a === void undefined && b === void undefined;"
      },
      {
        "name": "with strings",
        "exec": "var [a, b, c] = \"ab\";\nreturn a === \"a\" && b === \"b\" && c === void undefined;"
      },
      {
        "name": "with astral plane strings",
        "exec": "var [c] = \"𠮷𠮶\";\nreturn c === \"𠮷\";"
      },
      {
        "name": "with generator instances",
        "exec": "var [a, b, c] = (function*(){ yield 1; yield 2; }());\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "with generic iterables",
        "exec": "var [a, b, c] = global.__createIterableObject([1, 2]);\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "with instances of generic iterables",
        "exec": "var [a, b, c] = Object.create(global.__createIterableObject([1, 2]));\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\nvar [a, b] = iter;\nreturn closed;"
      },
      {
        "name": "trailing commas in iterable patterns",
        "exec": "var [a,] = [1];\nreturn a === 1;"
      },
      {
        "name": "with objects",
        "exec": "var {c, x:d, e} = {c:7, x:8};\nreturn c === 7 && d === 8 && e === void undefined;"
      },
      {
        "name": "object destructuring with primitives",
        "exec": "var {toFixed} = 2;\nvar {slice} = '';\nreturn toFixed === Number.prototype.toFixed\n  && slice === String.prototype.slice;"
      },
      {
        "name": "trailing commas in object patterns",
        "exec": "var {a,} = {a:1};\nreturn a === 1;"
      },
      {
        "name": "throws on null and undefined",
        "exec": "try {\n  var {a} = null;\n  return false;\n} catch(e) {\n  if (!(e instanceof TypeError))\n    return false;\n}\ntry {\n  var {b} = void undefined;\n  return false;\n} catch(e) {\n  if (!(e instanceof TypeError))\n    return false;\n}\nreturn true;"
      },
      {
        "name": "computed properties",
        "exec": "var qux = \"corge\";\nvar { [qux]: grault } = { corge: \"garply\" };\nreturn grault === \"garply\";"
      },
      {
        "name": "multiples in a single var statement",
        "exec": "var [a,b] = [5,6], {c,d} = {c:7,d:8};\nreturn a === 5 && b === 6 && c === 7 && d === 8;"
      },
      {
        "name": "nested",
        "exec": "var [e, {x:f, g}] = [9, {x:10}];\nvar {h, x:[i]} = {h:11, x:[12]};\nreturn e === 9 && f === 10 && g === void undefined\n  && h === 11 && i === 12;"
      },
      {
        "name": "in for-in loop heads",
        "exec": "for(var [i, j, k] in { qux: 1 }) {\n  return i === \"q\" && j === \"u\" && k === \"x\";\n}"
      },
      {
        "name": "in for-of loop heads",
        "exec": "for(var [i, j, k] of [[1,2,3]]) {\n  return i === 1 && j === 2 && k === 3;\n}"
      },
      {
        "name": "in catch heads",
        "exec": "try {\n  throw [1,2];\n} catch([i,j]) {\n  try {\n    throw { k: 3, l: 4 };\n  } catch({k, l}) {\n    return i === 1 && j === 2 && k === 3 && l === 4;\n  }\n}"
      },
      {
        "name": "rest",
        "exec": "var [a, ...b] = [3, 4, 5];\nvar [c, ...d] = [6];\nreturn a === 3 && b instanceof Array && (b + \"\") === \"4,5\" &&\n   c === 6 && d instanceof Array && d.length === 0;"
      },
      {
        "name": "defaults",
        "exec": "var {a = 1, b = 0, z:c = 3} = {b:2, z:undefined};\nvar [d = 0, e = 5, f = 6] = [4,,undefined];\nreturn a === 1 && b === 2 && c === 3\n  && d === 4 && e === 5 && f === 6;"
      },
      {
        "name": "defaults, let temporal dead zone",
        "exec": "var {a, b = 2} = {a:1};\ntry {\n  eval(\"let {c = c} = {};\");\n  return false;\n} catch(e){}\ntry {\n  eval(\"let {c = d, d} = {d:1};\");\n  return false;\n} catch(e){}\nreturn a === 1 && b === 2;"
      }
    ]
  },
  {
    "name": "destructuring, assignment",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-destructuring-assignment",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment",
    "subtests": [
      {
        "name": "with arrays",
        "exec": "var a,b,c;\n[a, , [b], c] = [5, null, [6]];\nreturn a === 5 && b === 6 && c === void undefined;"
      },
      {
        "name": "with sparse arrays",
        "exec": "var a, b;\n[a, , b] = [,,,];\nreturn a === void undefined && b === void undefined;"
      },
      {
        "name": "with strings",
        "exec": "var a,b,c;\n[a, b, c] = \"ab\";\nreturn a === \"a\" && b === \"b\" && c === void undefined;"
      },
      {
        "name": "with astral plane strings",
        "exec": "var c;\n[c] = \"𠮷𠮶\";\nreturn c === \"𠮷\";"
      },
      {
        "name": "with generator instances",
        "exec": "var a,b,c;\n[a, b, c] = (function*(){ yield 1; yield 2; }());\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "with generic iterables",
        "exec": "var a,b,c;\n[a, b, c] = global.__createIterableObject([1, 2]);\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "with instances of generic iterables",
        "exec": "var a,b,c;\n[a, b, c] = Object.create(global.__createIterableObject([1, 2]));\nreturn a === 1 && b === 2 && c === void undefined;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\nvar a,b;\n[a, b] = iter;\nreturn closed;"
      },
      {
        "name": "iterable destructuring expression",
        "exec": "var a, b, iterable = [1,2];\nreturn ([a, b] = iterable) === iterable;"
      },
      {
        "name": "chained iterable destructuring",
        "exec": "var a,b,c,d;\n[a,b] = [c,d] = [1,2];\nreturn a === 1 && b === 2 && c === 1 && d === 2;"
      },
      {
        "name": "trailing commas in iterable patterns",
        "exec": "var a;\n[a,] = [1];\nreturn a === 1;"
      },
      {
        "name": "with objects",
        "exec": "var c,d,e;\n({c, x:d, e} = {c:7, x:8});\nreturn c === 7 && d === 8 && e === void undefined;"
      },
      {
        "name": "object destructuring with primitives",
        "exec": "var toFixed, slice;\n({toFixed} = 2);\n({slice} = '');\nreturn toFixed === Number.prototype.toFixed\n  && slice === String.prototype.slice;"
      },
      {
        "name": "trailing commas in object patterns",
        "exec": "var a;\n({a,} = {a:1});\nreturn a === 1;"
      },
      {
        "name": "object destructuring expression",
        "exec": "var a, b, obj = { a:1, b:2 };\nreturn ({a,b} = obj) === obj;"
      },
      {
        "name": "parenthesised left-hand-side is a syntax error",
        "exec": "var a, b;\n({a,b} = {a:1,b:2});\ntry {\n  eval(\"({a,b}) = {a:3,b:4};\");\n}\ncatch(e) {\n  return a === 1 && b === 2;\n}"
      },
      {
        "name": "chained object destructuring",
        "exec": "var a,b,c,d;\n({a,b} = {c,d} = {a:1,b:2,c:3,d:4});\nreturn a === 1 && b === 2 && c === 3 && d === 4;"
      },
      {
        "name": "throws on null and undefined",
        "exec": "var a,b;\ntry {\n  ({a} = null);\n  return false;\n} catch(e) {\n  if (!(e instanceof TypeError))\n    return false;\n}\ntry {\n  ({b} = void undefined);\n  return false;\n} catch(e) {\n  if (!(e instanceof TypeError))\n    return false;\n}\nreturn true;"
      },
      {
        "name": "computed properties",
        "exec": "var grault, qux = \"corge\";\n({ [qux]: grault } = { corge: \"garply\" });\nreturn grault === \"garply\";"
      },
      {
        "name": "nested",
        "exec": "var e,f,g,h,i;\n[e, {x:f, g}] = [9, {x:10}];\n({h, x:[i]} = {h:11, x:[12]});\nreturn e === 9 && f === 10 && g === void undefined\n  && h === 11 && i === 12;"
      },
      {
        "name": "rest",
        "exec": "var a,b,c,d;\n[a, ...b] = [3, 4, 5];\n[c, ...d] = [6];\nreturn a === 3 && b instanceof Array && (b + \"\") === \"4,5\" &&\n   c === 6 && d instanceof Array && d.length === 0;"
      },
      {
        "name": "nested rest",
        "exec": "var a = [1, 2, 3], first, last;\n[first, ...[a[2], last]] = a;\nreturn first === 1 && last === 3 && (a + \"\") === \"1,2,2\";"
      },
      {
        "name": "empty patterns",
        "exec": "[] = [1,2];\n({} = {a:1,b:2});\nreturn true;"
      },
      {
        "name": "defaults",
        "exec": "var a,b,c,d,e,f;\n({a = 1, b = 0, z:c = 3} = {b:2, z:undefined});\n[d = 0, e = 5, f = 6] = [4,,undefined];\nreturn a === 1 && b === 2 && c === 3\n  && d === 4 && e === 5 && f === 6;"
      }
    ]
  },
  {
    "name": "destructuring, parameters",
    "target": "es6",
    "category": "syntax",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-destructuring-assignment",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment",
    "subtests": [
      {
        "name": "with arrays",
        "exec": "return function([a, , [b], c]) {\n  return a === 5 && b === 6 && c === void undefined;\n}([5, null, [6]]);"
      },
      {
        "name": "with sparse arrays",
        "exec": "return function([a, , b]) {\n  return a === void undefined && b === void undefined;\n}([,,,]);"
      },
      {
        "name": "with strings",
        "exec": "return function([a, b, c]) {\n  return a === \"a\" && b === \"b\" && c === void undefined;\n}(\"ab\");"
      },
      {
        "name": "with astral plane strings",
        "exec": "return function([c]) {\n  return c === \"𠮷\";\n}(\"𠮷𠮶\");"
      },
      {
        "name": "with generator instances",
        "exec": "return function([a, b, c]) {\n  return a === 1 && b === 2 && c === void undefined;\n}(function*(){ yield 1; yield 2; }());"
      },
      {
        "name": "with generic iterables",
        "exec": "return function([a, b, c]) {\n  return a === 1 && b === 2 && c === void undefined;\n}(global.__createIterableObject([1, 2]));"
      },
      {
        "name": "with instances of generic iterables",
        "exec": "return function([a, b, c]) {\n  return a === 1 && b === 2 && c === void undefined;\n}(Object.create(global.__createIterableObject([1, 2])));"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\n(function([a,b]) {}(iter));\nreturn closed;"
      },
      {
        "name": "trailing commas in iterable patterns",
        "exec": "return function([a,]) {\n  return a === 1;\n}([1]);"
      },
      {
        "name": "with objects",
        "exec": "return function({c, x:d, e}) {\n  return c === 7 && d === 8 && e === void undefined;\n}({c:7, x:8});"
      },
      {
        "name": "object destructuring with primitives",
        "exec": "return function({toFixed}, {slice}) {\n  return toFixed === Number.prototype.toFixed\n    && slice === String.prototype.slice;\n}(2,'');"
      },
      {
        "name": "trailing commas in object patterns",
        "exec": "return function({a,}) {\n  return a === 1;\n}({a:1});"
      },
      {
        "name": "throws on null and undefined",
        "exec": "try {\n  (function({a}){}(null));\n  return false;\n} catch(e) {}\ntry {\n  (function({b}){}(undefined));\n  return false;\n} catch(e) {}\nreturn true;"
      },
      {
        "name": "computed properties",
        "exec": "var qux = \"corge\";\nreturn function({ [qux]: grault }) {\n  return grault === \"garply\";\n}({ corge: \"garply\" });"
      },
      {
        "name": "nested",
        "exec": "return function([e, {x:f, g}], {h, x:[i]}) {\n  return e === 9 && f === 10 && g === void undefined\n    && h === 11 && i === 12;\n}([9, {x:10}],{h:11, x:[12]});"
      },
      {
        "name": "'arguments' interaction",
        "exec": "return (function({a, x:b, y:e}, [c, d]) {\n  return arguments[0].a === 1 && arguments[0].x === 2\n    && !(\"y\" in arguments[0]) && arguments[1] + '' === \"3,4\";\n}({a:1, x:2}, [3, 4]));"
      },
      {
        "name": "new Function() support",
        "exec": "return new Function(\"{a, x:b, y:e}\",\"[c, d]\",\n  \"return a === 1 && b === 2 && c === 3 && \"\n  + \"d === 4 && e === void undefined;\"\n)({a:1, x:2}, [3, 4]);"
      },
      {
        "name": "in parameters, function 'length' property",
        "exec": "return function({a, b}, [c, d]){}.length === 2;"
      },
      {
        "name": "rest",
        "exec": "return function([a, ...b], [c, ...d]) {\n  return a === 3 && b instanceof Array && (b + \"\") === \"4,5\" &&\n     c === 6 && d instanceof Array && d.length === 0;\n}([3, 4, 5], [6]);"
      },
      {
        "name": "empty patterns",
        "exec": "return function ([],{}){\n  return arguments[0] + '' === \"3,4\" && arguments[1].x === \"foo\";\n}([3,4],{x:\"foo\"});"
      },
      {
        "name": "defaults",
        "exec": "return (function({a = 1, b = 0, c = 3, x:d = 0, y:e = 5},\n    [f = 6, g = 0, h = 8]) {\n  return a === 1 && b === 2 && c === 3 && d === 4 &&\n    e === 5 && f === 6 && g === 7 && h === 8;\n}({b:2, c:undefined, x:4},[, 7, undefined]));"
      },
      {
        "name": "defaults, separate scope",
        "exec": "return (function({a=function(){\n  return typeof b === 'undefined';\n}}){\n  var b = 1;\n  return a();\n}({}));"
      },
      {
        "name": "defaults, new Function() support",
        "exec": "return new Function(\"{a = 1, b = 0, c = 3, x:d = 0, y:e = 5}\",\n  \"return a === 1 && b === 2 && c === 3 && d === 4 && e === 5;\"\n)({b:2, c:undefined, x:4});"
      },
      {
        "name": "aliased defaults, arrow function",
        "exec": "return ((a, {b: x = 0, c: y = 3}) => {\n  return a === 1 && x === 2 && y === 3;\n})(1, {b: 2});"
      },
      {
        "name": "shorthand defaults, arrow function",
        "exec": "return ((a, {b = 0, c = 3}) => {\n  return a === 1 && b === 2 && c === 3;\n})(1, {b: 2});"
      },
      {
        "name": "duplicate identifier",
        "exec": "try {\n  eval('var d = function d([d]) { return d };');\n  if (d([true]) !== true) return false;\n} catch (e) {\n  return !(e instanceof SyntaxError);\n}\n\ntry {\n  eval('var f = function f([id, id]) { return id }');\n  return false;\n} catch (e) {\n  return e instanceof SyntaxError;\n}"
      }
    ]
  },
  {
    "name": "Unicode code point escapes",
    "target": "es6",
    "category": "syntax",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-literals-string-literals",
    "subtests": [
      {
        "name": "in strings",
        "exec": "return '\\u{1d306}' === '\\ud834\\udf06';"
      },
      {
        "name": "in identifiers",
        "exec": "var \\u{102C0} = 2;\nreturn \\u{102C0} === 2;"
      },
      {
        "name": "in property key definitions",
        "exec": "var o = { \\u{102C0} : 2 };\nreturn o['\\ud800\\udec0'] === 2;"
      },
      {
        "name": "in property key accesses",
        "exec": "var o = { '\\ud800\\udec0' : 2 };\nreturn o.\\u{102C0} === 2;"
      }
    ]
  },
  {
    "name": "new.target",
    "target": "es6",
    "category": "syntax",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-built-in-function-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new.target",
    "subtests": [
      {
        "name": "in constructors",
        "exec": "var passed = false;\nnew function f() {\n  passed = (new.target === f);\n}();\n(function() {\n  passed &= (new.target === void undefined);\n}());\nreturn passed;"
      },
      {
        "name": "assignment is an early error",
        "exec": "var passed = false;\nnew function f() {\n  passed = (new.target === f);\n}();\n\ntry {\n  Function(\"new.target = function(){};\");\n} catch(e) {\n  return passed;\n}"
      }
    ]
  },
  {
    "name": "const",
    "target": "es6",
    "category": "bindings",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-let-and-const-declarations",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const",
    "subtests": [
      {
        "name": "basic support",
        "exec": "const foo = 123;\nreturn (foo === 123);"
      },
      {
        "name": "is block-scoped",
        "exec": "const bar = 123;\n{ const bar = 456; }\nreturn bar === 123;"
      },
      {
        "name": "scope shadow resolution",
        "exec": "try {\n    { const bar = 456; }\n    const bar = 123;\n    return bar === 123;\n} catch(e) {\n  return false;\n}"
      },
      {
        "name": "cannot be in statements",
        "exec": "const bar = 1;\ntry {\n  Function(\"if(true) const baz = 1;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "redefining a const is an error",
        "exec": "const baz = 1;\ntry {\n  Function(\"const foo = 1; foo = 2;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "for loop statement scope",
        "exec": "const baz = 1;\nfor(const baz = 0; false;) {}\nreturn baz === 1;"
      },
      {
        "name": "for-in loop iteration scope",
        "exec": "var scopes = [];\nfor(const i in { a:1, b:1 }) {\n  scopes.push(function(){ return i; });\n}\nreturn (scopes[0]() === \"a\" && scopes[1]() === \"b\");"
      },
      {
        "name": "for-of loop iteration scope",
        "exec": "var scopes = [];\nfor(const i of ['a','b']) {\n  scopes.push(function(){ return i; });\n}\nreturn (scopes[0]() === \"a\" && scopes[1]() === \"b\");"
      },
      {
        "name": "temporal dead zone",
        "exec": "var passed = (function(){ try { qux; } catch(e) { return true; }}());\nfunction fn() { passed &= qux === 456; }\nconst qux = 456;\nfn();\nreturn passed;"
      },
      {
        "name": "basic support (strict mode)",
        "exec": "\"use strict\";\nconst foo = 123;\nreturn (foo === 123);"
      },
      {
        "name": "is block-scoped (strict mode)",
        "exec": "'use strict';\nconst bar = 123;\n{ const bar = 456; }\nreturn bar === 123;"
      },
      {
        "name": "scope shadow resolution (strict mode)",
        "exec": "'use strict';\ntry {\n    { const bar = 456; }\n    const bar = 123;\n    return bar === 123;\n} catch(e) {\n  return false;\n}"
      },
      {
        "name": "cannot be in statements (strict mode)",
        "exec": "'use strict';\nconst bar = 1;\ntry {\n  Function(\"'use strict'; if(true) const baz = 1;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "redefining a const (strict mode)",
        "exec": "'use strict';\nconst baz = 1;\ntry {\n  Function(\"'use strict'; const foo = 1; foo = 2;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "for loop statement scope (strict mode)",
        "exec": "'use strict';\nconst baz = 1;\nfor(const baz = 0; false;) {}\nreturn baz === 1;"
      },
      {
        "name": "for-in loop iteration scope (strict mode)",
        "exec": "'use strict';\nvar scopes = [];\nfor(const i in { a:1, b:1 }) {\n  scopes.push(function(){ return i; });\n}\nreturn (scopes[0]() === \"a\" && scopes[1]() === \"b\");"
      },
      {
        "name": "for-of loop iteration scope (strict mode)",
        "exec": "'use strict';\nvar scopes = [];\nfor(const i of ['a','b']) {\n  scopes.push(function(){ return i; });\n}\nreturn (scopes[0]() === \"a\" && scopes[1]() === \"b\");"
      },
      {
        "name": "temporal dead zone (strict mode)",
        "exec": "'use strict';\nvar passed = (function(){ try { qux; } catch(e) { return true; }}());\nfunction fn() { passed &= qux === 456; }\nconst qux = 456;\nfn();\nreturn passed;"
      }
    ]
  },
  {
    "name": "let",
    "target": "es6",
    "category": "bindings",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-let-and-const-declarations",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let",
    "subtests": [
      {
        "name": "basic support",
        "exec": "let foo = 123;\nreturn (foo === 123);"
      },
      {
        "name": "is block-scoped",
        "exec": "let bar = 123;\n{ let bar = 456; }\nreturn bar === 123;"
      },
      {
        "name": "scope shadow resolution",
        "exec": "try {\n    { let bar = 456; }\n    let bar = 123;\n    return bar === 123;\n} catch(e) {\n  return false;\n}"
      },
      {
        "name": "cannot be in statements",
        "exec": "let bar = 1;\ntry {\n  Function(\"if(true) let baz = 1;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "for loop statement scope",
        "exec": "let baz = 1;\nfor(let baz = 0; false;) {}\nreturn baz === 1;"
      },
      {
        "name": "temporal dead zone",
        "exec": "var passed = (function(){ try {  qux; } catch(e) { return true; }}());\nfunction fn() { passed &= qux === 456; }\nlet qux = 456;\nfn();\nreturn passed;"
      },
      {
        "name": "for/for-in loop iteration scope",
        "exec": "let scopes = [];\nfor(let i = 0; i < 2; i++) {\n  scopes.push(function(){ return i; });\n}\nlet passed = (scopes[0]() === 0 && scopes[1]() === 1);\n\nscopes = [];\nfor(let i in { a:1, b:1 }) {\n  scopes.push(function(){ return i; });\n}\npassed &= (scopes[0]() === \"a\" && scopes[1]() === \"b\");\nreturn passed;"
      },
      {
        "name": "for-in loop binding shadowing parameter",
        "exec": "try {\n  Function(\"function f(e) { for (let e in {}) e }\");\n  return true;\n} catch(e) {\n  return false;\n}"
      },
      {
        "name": "basic support (strict mode)",
        "exec": "'use strict';\nlet foo = 123;\nreturn (foo === 123);"
      },
      {
        "name": "is block-scoped (strict mode)",
        "exec": "'use strict';\nlet bar = 123;\n{ let bar = 456; }\nreturn bar === 123;"
      },
      {
        "name": "scope shadow resolution (strict mode)",
        "exec": "'use strict';\ntry {\n    { let bar = 456; }\n    let bar = 123;\n    return bar === 123;\n} catch(e) {\n  return false;\n}"
      },
      {
        "name": "cannot be in statements (strict mode)",
        "exec": "'use strict';\nlet bar = 1;\ntry {\n  Function(\"'use strict'; if(true) let baz = 1;\")();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "for loop statement scope (strict mode)",
        "exec": "'use strict';\nlet baz = 1;\nfor(let baz = 0; false;) {}\nreturn baz === 1;"
      },
      {
        "name": "temporal dead zone (strict mode)",
        "exec": "'use strict';\nvar passed = (function(){ try {  qux; } catch(e) { return true; }}());\nfunction fn() { passed &= qux === 456; }\nlet qux = 456;\nfn();\nreturn passed;"
      },
      {
        "name": "for/for-in loop iteration scope (strict mode)",
        "exec": "'use strict';\nlet scopes = [];\nfor(let i = 0; i < 2; i++) {\n  scopes.push(function(){ return i; });\n}\nlet passed = (scopes[0]() === 0 && scopes[1]() === 1);\n\nscopes = [];\nfor(let i in { a:1, b:1 }) {\n  scopes.push(function(){ return i; });\n}\npassed &= (scopes[0]() === \"a\" && scopes[1]() === \"b\");\nreturn passed;"
      },
      {
        "name": "for-in loop binding shadowing parameter (strict mode)",
        "exec": "try {\n  Function(\"'use strict'; function f(e) { for (let e in {}) e }\");\n  return true;\n} catch(e) {\n  return false;\n}"
      }
    ]
  },
  {
    "name": "block-level function declaration",
    "target": "es6",
    "category": "bindings",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-functiondeclarationinstantiation",
    "exec": "'use strict';\nif (f() !== 1) return false;\nfunction f() { return 1; }\n{\n  if (f() !== 2) return false;\n  function f() { return 2; }\n  if (f() !== 2) return false;\n}\nif (f() !== 1) return false;\nreturn true;"
  },
  {
    "name": "arrow functions",
    "target": "es6",
    "category": "functions",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-arrow-function-definitions",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions",
    "subtests": [
      {
        "name": "0 parameters",
        "exec": "return (() => 5)() === 5;"
      },
      {
        "name": "1 parameter, no brackets",
        "exec": "var b = x => x + \"foo\";\nreturn (b(\"fee fie foe \") === \"fee fie foe foo\");"
      },
      {
        "name": "multiple parameters",
        "exec": "var c = (v, w, x, y, z) => \"\" + v + w + x + y + z;\nreturn (c(6, 5, 4, 3, 2) === \"65432\");"
      },
      {
        "name": "lexical \"this\" binding",
        "exec": "var d = { x : \"bar\", y : function() { return z => this.x + z; }}.y();\nvar e = { x : \"baz\", y : d };\nreturn d(\"ley\") === \"barley\" && e.y(\"ley\") === \"barley\";"
      },
      {
        "name": "\"this\" unchanged by call or apply",
        "exec": "var d = { x : \"foo\", y : function() { return () => this.x; }};\nvar e = { x : \"bar\" };\nreturn d.y().call(e) === \"foo\" && d.y().apply(e) === \"foo\";"
      },
      {
        "name": "can't be bound, can be curried",
        "exec": "var d = { x : \"bar\", y : function() { return z => this.x + z; }};\nvar e = { x : \"baz\" };\nreturn d.y().bind(e, \"ley\")() === \"barley\";"
      },
      {
        "name": "lexical \"arguments\" binding",
        "exec": "var f = (function() { return z => arguments[0]; }(5));\nreturn f(6) === 5;"
      },
      {
        "name": "no line break between params and <code>=></code>",
        "exec": "return (() => {\n  try { Function(\"x\\n => 2\")(); } catch(e) { return true; }\n})();"
      },
      {
        "name": "correct precedence",
        "exec": "return (() => {\n  try { Function(\"0 || () => 2\")(); } catch(e) { return true; }\n})();"
      },
      {
        "name": "no \"prototype\" property",
        "exec": "var a = () => 5;\nreturn !a.hasOwnProperty(\"prototype\");"
      },
      {
        "name": "lexical \"super\" binding in constructors",
        "exec": "var received;\n\nclass B {\n  constructor (arg) {\n    received = arg;\n  }\n}\nclass C extends B {\n  constructor () {\n    var callSuper = () => super('foo');\n    callSuper();\n  }\n}\nreturn new C instanceof C && received === 'foo'"
      },
      {
        "name": "lexical \"super\" binding in methods",
        "exec": "class B {\n  qux() {\n    return \"quux\";\n  }\n}\nclass C extends B {\n  baz() {\n    return x => super.qux();\n  }\n}\nvar arrow = new C().baz();\nreturn arrow() === \"quux\";"
      },
      {
        "name": "lexical \"new.target\" binding",
        "exec": "function C() {\n  return x => new.target;\n}\nreturn new C()() === C && C()() === void undefined;"
      }
    ]
  },
  {
    "name": "class",
    "target": "es6",
    "category": "functions",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-class-definitions",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes",
    "subtests": [
      {
        "name": "class statement",
        "exec": "class C {}\nreturn typeof C === \"function\";"
      },
      {
        "name": "is block-scoped",
        "exec": "class C {}\nvar c1 = C;\n{\n  class C {}\n  var c2 = C;\n}\nreturn C === c1;"
      },
      {
        "name": "class expression",
        "exec": "return typeof class C {} === \"function\";"
      },
      {
        "name": "anonymous class",
        "exec": "return typeof class {} === \"function\";"
      },
      {
        "name": "constructor",
        "exec": "class C {\n  constructor() { this.x = 1; }\n}\nreturn C.prototype.constructor === C\n  && new C().x === 1;"
      },
      {
        "name": "prototype methods",
        "exec": "class C {\n  method() { return 2; }\n}\nreturn typeof C.prototype.method === \"function\"\n  && new C().method() === 2;"
      },
      {
        "name": "string-keyed methods",
        "exec": "class C {\n  \"foo bar\"() { return 2; }\n}\nreturn typeof C.prototype[\"foo bar\"] === \"function\"\n  && new C()[\"foo bar\"]() === 2;"
      },
      {
        "name": "computed prototype methods",
        "exec": "var foo = \"method\";\nclass C {\n  [foo]() { return 2; }\n}\nreturn typeof C.prototype.method === \"function\"\n  && new C().method() === 2;"
      },
      {
        "name": "optional semicolons",
        "exec": "class C {\n  ;\n  method() { return 2; };\n  method2() { return 2; }\n  method3() { return 2; };\n}\nreturn typeof C.prototype.method === \"function\"\n  && typeof C.prototype.method2 === \"function\"\n  && typeof C.prototype.method3 === \"function\";"
      },
      {
        "name": "static methods",
        "exec": "class C {\n  static method() { return 3; }\n}\nreturn typeof C.method === \"function\"\n  && C.method() === 3;"
      },
      {
        "name": "computed static methods",
        "exec": "var foo = \"method\";\nclass C {\n  static [foo]() { return 3; }\n}\nreturn typeof C.method === \"function\"\n  && C.method() === 3;"
      },
      {
        "name": "accessor properties",
        "exec": "var baz = false;\nclass C {\n  get foo() { return \"foo\"; }\n  set bar(x) { baz = x; }\n}\nnew C().bar = true;\nreturn new C().foo === \"foo\" && baz;"
      },
      {
        "name": "computed accessor properties",
        "exec": "var garply = \"foo\", grault = \"bar\", baz = false;\nclass C {\n  get [garply]() { return \"foo\"; }\n  set [grault](x) { baz = x; }\n}\nnew C().bar = true;\nreturn new C().foo === \"foo\" && baz;"
      },
      {
        "name": "static accessor properties",
        "exec": "var baz = false;\nclass C {\n  static get foo() { return \"foo\"; }\n  static set bar(x) { baz = x; }\n}\nC.bar = true;\nreturn C.foo === \"foo\" && baz;"
      },
      {
        "name": "computed static accessor properties",
        "exec": "var garply = \"foo\", grault = \"bar\", baz = false;\nclass C {\n  static get [garply]() { return \"foo\"; }\n  static set [grault](x) { baz = x; }\n}\nC.bar = true;\nreturn C.foo === \"foo\" && baz;"
      },
      {
        "name": "class name is lexically scoped",
        "exec": "class C {\n  method() { return typeof C === \"function\"; }\n}\nvar M = C.prototype.method;\nC = void undefined;\nreturn C === void undefined && M();"
      },
      {
        "name": "computed names, temporal dead zone",
        "exec": "try {\n  var B = class C {\n    [C](){}\n  }\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "methods aren't enumerable",
        "exec": "class C {\n  foo() {}\n  static bar() {}\n}\nreturn !C.prototype.propertyIsEnumerable(\"foo\") && !C.propertyIsEnumerable(\"bar\");"
      },
      {
        "name": "implicit strict mode",
        "exec": "class C {\n  static method() { return this === void undefined; }\n}\nreturn (0,C.method)();"
      },
      {
        "name": "constructor requires new",
        "exec": "class C {}\ntry {\n  C();\n}\ncatch(e) {\n  return true;\n}"
      },
      {
        "name": "extends",
        "exec": "class B {}\nclass C extends B {}\nreturn new C() instanceof B\n  && B.isPrototypeOf(C);"
      },
      {
        "name": "extends expressions",
        "exec": "var B;\nclass C extends (B = class {}) {}\nreturn new C() instanceof B\n  && B.isPrototypeOf(C);"
      },
      {
        "name": "extends null",
        "exec": "class C extends null {\n  constructor() { return Object.create(null); }\n}\nreturn Function.prototype.isPrototypeOf(C)\n  && Object.getPrototypeOf(C.prototype) === null;"
      },
      {
        "name": "new.target",
        "exec": "var passed = false;\nnew function f() {\n  passed = new.target === f;\n}();\n\nclass A {\n  constructor() {\n    passed &= new.target === B;\n  }\n}\nclass B extends A {}\nnew B();\nreturn passed;"
      }
    ]
  },
  {
    "name": "super",
    "target": "es6",
    "category": "functions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-super-keyword",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/super",
    "subtests": [
      {
        "name": "statement in constructors",
        "exec": "var passed = false;\nclass B {\n  constructor(a) { passed = (a === \"barbaz\"); }\n}\nclass C extends B {\n  constructor(a) { super(\"bar\" + a); }\n}\nnew C(\"baz\");\nreturn passed;"
      },
      {
        "name": "expression in constructors",
        "exec": "class B {\n  constructor(a) { return [\"foo\" + a]; }\n}\nclass C extends B {\n  constructor(a) { return super(\"bar\" + a); }\n}\nreturn new C(\"baz\")[0] === \"foobarbaz\";"
      },
      {
        "name": "in methods, property access",
        "exec": "class B {}\nB.prototype.qux = \"foo\";\nB.prototype.corge = \"baz\";\nclass C extends B {\n  quux(a) { return super.qux + a + super[\"corge\"]; }\n}\nC.prototype.qux = \"garply\";\nreturn new C().quux(\"bar\") === \"foobarbaz\";"
      },
      {
        "name": "in methods, method calls",
        "exec": "class B {\n  qux(a) { return \"foo\" + a; }\n}\nclass C extends B {\n  qux(a) { return super.qux(\"bar\" + a); }\n}\nreturn new C().qux(\"baz\") === \"foobarbaz\";"
      },
      {
        "name": "method calls use correct \"this\" binding",
        "exec": "class B {\n  qux(a) { return this.foo + a; }\n}\nclass C extends B {\n  qux(a) { return super.qux(\"bar\" + a); }\n}\nvar obj = new C();\nobj.foo = \"foo\";\nreturn obj.qux(\"baz\") === \"foobarbaz\";"
      },
      {
        "name": "constructor calls use correct \"new.target\" binding",
        "exec": "var passed;\nclass B {\n  constructor() { passed = (new.target === C); }\n}\nclass C extends B {\n  constructor() { super(); }\n}\nnew C();\nreturn passed;"
      },
      {
        "name": "is statically bound",
        "exec": "class B {\n  qux() { return \"bar\"; }\n}\nclass C extends B {\n  qux() { return super.qux() + this.corge; }\n}\nvar obj = {\n  qux: C.prototype.qux,\n  corge: \"ley\"\n};\nreturn obj.qux() === \"barley\";"
      },
      {
        "name": "super() invokes the correct constructor",
        "exec": "// checks that super() is *not* a synonym of super.constructor()\nvar passed;\nclass B {\n    constructor() {\n        passed = true;\n    }\n};\nB.prototype.constructor = function () {\n    passed = false;\n};\nclass C extends B { };\nnew C;\nreturn passed;"
      }
    ]
  },
  {
    "name": "generators",
    "target": "es6",
    "category": "functions",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-generator-function-definitions",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "function * generator(){\n  yield 5; yield 6;\n};\nvar iterator = generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "generator function expressions",
        "exec": "var generator = function * (){\n  yield 5; yield 6;\n};\nvar iterator = generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "correct \"this\" binding",
        "exec": "function * generator(){\n  yield this.x; yield this.y;\n};\nvar iterator = { g: generator, x: 5, y: 6 }.g();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "can't use \"this\" with new",
        "exec": "function * generator(){\n  yield this.x; yield this.y;\n};\ntry {\n  (new generator()).next();\n}\ncatch (e) {\n  return true;\n}"
      },
      {
        "name": "sending",
        "exec": "var sent;\nfunction * generator(){\n  sent = [yield 5, yield 6];\n};\nvar iterator = generator();\niterator.next();\niterator.next(\"foo\");\niterator.next(\"bar\");\nreturn sent[0] === \"foo\" && sent[1] === \"bar\";"
      },
      {
        "name": "%GeneratorPrototype%",
        "exec": "function * generatorFn(){}\nvar ownProto = Object.getPrototypeOf(generatorFn());\nvar passed = ownProto === generatorFn.prototype;\n\nvar sharedProto = Object.getPrototypeOf(ownProto);\npassed &= sharedProto !== Object.prototype &&\n  sharedProto === Object.getPrototypeOf(function*(){}.prototype) &&\n  sharedProto.hasOwnProperty('next');\n\nreturn passed;"
      },
      {
        "name": "%GeneratorPrototype% prototype chain",
        "exec": "function * generatorFn(){}\nvar g = generatorFn();\nvar ownProto = Object.getPrototypeOf(g);\nvar passed = ownProto === generatorFn.prototype;\n\nvar sharedProto = Object.getPrototypeOf(ownProto);\nvar iterProto = Object.getPrototypeOf(sharedProto);\n\npassed &= iterProto.hasOwnProperty(Symbol.iterator) &&\n  !sharedProto     .hasOwnProperty(Symbol.iterator) &&\n  !ownProto        .hasOwnProperty(Symbol.iterator) &&\n  g[Symbol.iterator]() === g;\n\nreturn passed;"
      },
      {
        "name": "%GeneratorPrototype%.constructor",
        "exec": "function * g (){}\nvar iterator = new g.constructor(\"a\",\"b\",\"c\",\"yield a; yield b; yield c;\")(5,6,7);\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 7 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\n\npassed &= g.constructor === (function*(){}).constructor;\nreturn passed;"
      },
      {
        "name": "%GeneratorPrototype%.throw",
        "exec": "var passed = false;\nfunction * generator(){\n  try {\n    yield 5; yield 6;\n  } catch(e) {\n    passed = (e === \"foo\");\n  }\n};\nvar iterator = generator();\niterator.next();\niterator.throw(\"foo\");\nreturn passed;"
      },
      {
        "name": "%GeneratorPrototype%.return",
        "exec": "function * generator(){\n  yield 5; yield 6;\n};\nvar iterator = generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.return(\"quxquux\");\npassed &= item.value === \"quxquux\" && item.done === true;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield operator precedence",
        "exec": "var passed;\nfunction * generator(){\n  passed = yield 0 ? true : false;\n};\nvar iterator = generator();\niterator.next();\niterator.next(true);\nreturn passed;"
      },
      {
        "name": "yield *, arrays",
        "exec": "var iterator = (function * generator() {\n  yield * [5, 6];\n}());\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, sparse arrays",
        "exec": "var iterator = (function * generator() {\n  yield * [,,];\n}());\nvar item = iterator.next();\nvar passed = item.value === void undefined && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, strings",
        "exec": "var iterator = (function * generator() {\n  yield * \"56\";\n}());\nvar item = iterator.next();\nvar passed = item.value === \"5\" && item.done === false;\nitem = iterator.next();\npassed &= item.value === \"6\" && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, astral plane strings",
        "exec": "var iterator = (function * generator() {\n  yield * \"𠮷𠮶\";\n}());\nvar item = iterator.next();\nvar passed = item.value === \"𠮷\" && item.done === false;\nitem = iterator.next();\npassed &= item.value === \"𠮶\" && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, generator instances",
        "exec": "var iterator = (function * generator() {\n  yield * (function*(){ yield 5; yield 6; yield 7; }());\n}());\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 7 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, generic iterables",
        "exec": "var iterator = (function * generator() {\n  yield * global.__createIterableObject([5, 6, 7]);\n}());\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 7 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield *, instances of iterables",
        "exec": "var iterator = (function * generator() {\n  yield * Object.create(__createIterableObject([5, 6, 7]));\n}());\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 7 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "yield * on non-iterables is a runtime error",
        "exec": "var iterator = (function * generator() {\n  yield * [5];\n}());\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\niterator = (function * generator() {\n  yield * 5;\n}());\ntry {\n  iterator.next();\n} catch (e) {\n  return passed;\n}"
      },
      {
        "name": "yield *, iterator closing",
        "exec": "var closed = '';\nvar iter = __createIterableObject([1, 2, 3], {\n  'return': function(){\n    closed += 'a';\n    return {done: true};\n  }\n});\nvar gen = (function* generator(){\n  try {\n    yield *iter;\n  } finally {\n    closed += 'b';\n  }\n})();\ngen.next();\ngen['return']();\nreturn closed === 'ab';"
      },
      {
        "name": "yield *, iterator closing via throw()",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'throw': undefined,\n  'return': function() {\n    closed = true;\n    return {done: true};\n  }\n});\nvar gen = (function*(){\n  try {\n    yield *iter;\n  } catch(e){}\n})();\ngen.next();\ngen['throw']();\nreturn closed;"
      },
      {
        "name": "shorthand generator methods",
        "exec": "var o = {\n  * generator() {\n    yield 5; yield 6;\n  }\n};\nvar iterator = o.generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "string-keyed shorthand generator methods",
        "exec": "var o = {\n  * \"foo bar\"() {\n    yield 5; yield 6;\n  }\n};\nvar iterator = o[\"foo bar\"]();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "computed shorthand generators",
        "exec": "var garply = \"generator\";\nvar o = {\n  * [garply] () {\n    yield 5; yield 6;\n  }\n};\nvar iterator = o.generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "shorthand generator methods, classes",
        "exec": "class C {\n  * generator() {\n    yield 5; yield 6;\n  }\n};\nvar iterator = new C().generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "computed shorthand generators, classes",
        "exec": "var garply = \"generator\";\nclass C {\n  * [garply] () {\n    yield 5; yield 6;\n  }\n}\nvar iterator = new C().generator();\nvar item = iterator.next();\nvar passed = item.value === 5 && item.done === false;\nitem = iterator.next();\npassed &= item.value === 6 && item.done === false;\nitem = iterator.next();\npassed &= item.value === void undefined && item.done === true;\nreturn passed;"
      },
      {
        "name": "shorthand generators can't be constructors",
        "exec": "class C {\n  * generator() {\n    yield 5; yield 6;\n  }\n};\ntry {\n  Function(\"class D { * constructor() { return {}; } }\");\n} catch(e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "typed arrays",
    "target": "es6",
    "category": "built-ins",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-typedarray-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray",
    "subtests": [
      {
        "name": "Int8Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Int8Array(buffer);         view[0] = 0x80;\nreturn view[0] === -0x80;"
      },
      {
        "name": "Uint8Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Uint8Array(buffer);        view[0] = 0x100;\nreturn view[0] === 0;"
      },
      {
        "name": "Uint8ClampedArray",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Uint8ClampedArray(buffer); view[0] = 0x100;\nreturn view[0] === 0xFF;"
      },
      {
        "name": "Int16Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Int16Array(buffer);        view[0] = 0x8000;\nreturn view[0] === -0x8000;"
      },
      {
        "name": "Uint16Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Uint16Array(buffer);       view[0] = 0x10000;\nreturn view[0] === 0;"
      },
      {
        "name": "Int32Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Int32Array(buffer);        view[0] = 0x80000000;\nreturn view[0] === -0x80000000;"
      },
      {
        "name": "Uint32Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Uint32Array(buffer);       view[0] = 0x100000000;\nreturn view[0] === 0;"
      },
      {
        "name": "Float32Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Float32Array(buffer);       view[0] = 0.1;\nreturn view[0] === 0.10000000149011612;"
      },
      {
        "name": "Float64Array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new Float64Array(buffer);       view[0] = 0.1;\nreturn view[0] === 0.1;"
      },
      {
        "name": "DataView (Int8)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setInt8 (0, 0x80);\nreturn view.getInt8(0) === -0x80;"
      },
      {
        "name": "DataView (Uint8)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setUint8(0, 0x100);\nreturn view.getUint8(0) === 0;"
      },
      {
        "name": "DataView (Int16)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setInt16(0, 0x8000);\nreturn view.getInt16(0) === -0x8000;"
      },
      {
        "name": "DataView (Uint16)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setUint16(0, 0x10000);\nreturn view.getUint16(0) === 0;"
      },
      {
        "name": "DataView (Int32)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setInt32(0, 0x80000000);\nreturn view.getInt32(0) === -0x80000000;"
      },
      {
        "name": "DataView (Uint32)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setUint32(0, 0x100000000);\nreturn view.getUint32(0) === 0;"
      },
      {
        "name": "DataView (Float32)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setFloat32(0, 0.1);\nreturn view.getFloat32(0) === 0.10000000149011612;"
      },
      {
        "name": "DataView (Float64)",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setFloat64(0, 0.1);\nreturn view.getFloat64(0) === 0.1;"
      },
      {
        "name": "ArrayBuffer[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/@@species",
        "exec": "return typeof ArrayBuffer[Symbol.species] === 'function';"
      },
      {
        "name": "constructors require new",
        "exec": "var buffer = new ArrayBuffer(64);\nvar constructors = [\n  'ArrayBuffer',\n  'DataView',\n  'Int8Array',\n  'Uint8Array',\n  'Uint8ClampedArray',\n  'Int16Array',\n  'Uint16Array',\n  'Int32Array',\n  'Uint32Array',\n  'Float32Array',\n  'Float64Array'\n];\nreturn constructors.every(function (constructor) {\n  try {\n    if (constructor in global) {\n      global[constructor](constructor === \"ArrayBuffer\" ? 64 : buffer);\n    }\n    return false;\n  } catch(e) {\n    return true;\n  }\n});"
      },
      {
        "name": "constructors accept generic iterables",
        "exec": "var constructors = [\n  'Int8Array',\n  'Uint8Array',\n  'Uint8ClampedArray',\n  'Int16Array',\n  'Uint16Array',\n  'Int32Array',\n  'Uint32Array',\n  'Float32Array',\n  'Float64Array'\n];\nfor(var i = 0; i < constructors.length; i++){\n  var arr = new global[constructors[i]](__createIterableObject([1, 2, 3]));\n  if(arr.length !== 3 || arr[0] !== 1 || arr[1] !== 2 || arr[2] !== 3)return false;\n}\nreturn true;"
      },
      {
        "name": "correct prototype chains",
        "exec": "var constructors = [\n  'Int8Array',\n  'Uint8Array',\n  'Uint8ClampedArray',\n  'Int16Array',\n  'Uint16Array',\n  'Int32Array',\n  'Uint32Array',\n  'Float32Array',\n  'Float64Array'\n];\nvar constructor = Object.getPrototypeOf(Int8Array);\nvar prototype = Object.getPrototypeOf(Int8Array.prototype);\nif(constructor === Function.prototype || prototype === Object.prototype)return false;\nfor(var i = 0; i < constructors.length; i+=1) {\n  if (!(constructors[i] in global\n      && Object.getPrototypeOf(global[constructors[i]]) === constructor\n      && Object.getPrototypeOf(global[constructors[i]].prototype) === prototype\n      && Object.getOwnPropertyNames(global[constructors[i]].prototype).sort() + ''\n        === \"BYTES_PER_ELEMENT,constructor\")) {\n    return false;\n  }\n}\nreturn true;"
      },
      {
        "name": "%TypedArray%.from",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from",
        "exec": "return typeof Int8Array.from === \"function\" &&\ntypeof Uint8Array.from === \"function\" &&\ntypeof Uint8ClampedArray.from === \"function\" &&\ntypeof Int16Array.from === \"function\" &&\ntypeof Uint16Array.from === \"function\" &&\ntypeof Int32Array.from === \"function\" &&\ntypeof Uint32Array.from === \"function\" &&\ntypeof Float32Array.from === \"function\" &&\ntypeof Float64Array.from === \"function\";"
      },
      {
        "name": "%TypedArray%.of",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/of",
        "exec": "return typeof Int8Array.of === \"function\" &&\ntypeof Uint8Array.of === \"function\" &&\ntypeof Uint8ClampedArray.of === \"function\" &&\ntypeof Int16Array.of === \"function\" &&\ntypeof Uint16Array.of === \"function\" &&\ntypeof Int32Array.of === \"function\" &&\ntypeof Uint32Array.of === \"function\" &&\ntypeof Float32Array.of === \"function\" &&\ntypeof Float64Array.of === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.subarray",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/subarray",
        "exec": "return typeof Int8Array.prototype.subarray === \"function\" &&\ntypeof Uint8Array.prototype.subarray === \"function\" &&\ntypeof Uint8ClampedArray.prototype.subarray === \"function\" &&\ntypeof Int16Array.prototype.subarray === \"function\" &&\ntypeof Uint16Array.prototype.subarray === \"function\" &&\ntypeof Int32Array.prototype.subarray === \"function\" &&\ntypeof Uint32Array.prototype.subarray === \"function\" &&\ntypeof Float32Array.prototype.subarray === \"function\" &&\ntypeof Float64Array.prototype.subarray === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.join",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/join",
        "exec": "return typeof Int8Array.prototype.join === \"function\" &&\ntypeof Uint8Array.prototype.join === \"function\" &&\ntypeof Uint8ClampedArray.prototype.join === \"function\" &&\ntypeof Int16Array.prototype.join === \"function\" &&\ntypeof Uint16Array.prototype.join === \"function\" &&\ntypeof Int32Array.prototype.join === \"function\" &&\ntypeof Uint32Array.prototype.join === \"function\" &&\ntypeof Float32Array.prototype.join === \"function\" &&\ntypeof Float64Array.prototype.join === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.indexOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/indexOf",
        "exec": "return typeof Int8Array.prototype.indexOf === \"function\" &&\ntypeof Uint8Array.prototype.indexOf === \"function\" &&\ntypeof Uint8ClampedArray.prototype.indexOf === \"function\" &&\ntypeof Int16Array.prototype.indexOf === \"function\" &&\ntypeof Uint16Array.prototype.indexOf === \"function\" &&\ntypeof Int32Array.prototype.indexOf === \"function\" &&\ntypeof Uint32Array.prototype.indexOf === \"function\" &&\ntypeof Float32Array.prototype.indexOf === \"function\" &&\ntypeof Float64Array.prototype.indexOf === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.lastIndexOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/lastIndexOf",
        "exec": "return typeof Int8Array.prototype.lastIndexOf === \"function\" &&\ntypeof Uint8Array.prototype.lastIndexOf === \"function\" &&\ntypeof Uint8ClampedArray.prototype.lastIndexOf === \"function\" &&\ntypeof Int16Array.prototype.lastIndexOf === \"function\" &&\ntypeof Uint16Array.prototype.lastIndexOf === \"function\" &&\ntypeof Int32Array.prototype.lastIndexOf === \"function\" &&\ntypeof Uint32Array.prototype.lastIndexOf === \"function\" &&\ntypeof Float32Array.prototype.lastIndexOf === \"function\" &&\ntypeof Float64Array.prototype.lastIndexOf === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.slice",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/slice",
        "exec": "return typeof Int8Array.prototype.slice === \"function\" &&\ntypeof Uint8Array.prototype.slice === \"function\" &&\ntypeof Uint8ClampedArray.prototype.slice === \"function\" &&\ntypeof Int16Array.prototype.slice === \"function\" &&\ntypeof Uint16Array.prototype.slice === \"function\" &&\ntypeof Int32Array.prototype.slice === \"function\" &&\ntypeof Uint32Array.prototype.slice === \"function\" &&\ntypeof Float32Array.prototype.slice === \"function\" &&\ntypeof Float64Array.prototype.slice === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.every",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/every",
        "exec": "return typeof Int8Array.prototype.every === \"function\" &&\ntypeof Uint8Array.prototype.every === \"function\" &&\ntypeof Uint8ClampedArray.prototype.every === \"function\" &&\ntypeof Int16Array.prototype.every === \"function\" &&\ntypeof Uint16Array.prototype.every === \"function\" &&\ntypeof Int32Array.prototype.every === \"function\" &&\ntypeof Uint32Array.prototype.every === \"function\" &&\ntypeof Float32Array.prototype.every === \"function\" &&\ntypeof Float64Array.prototype.every === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.filter",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/filter",
        "exec": "return typeof Int8Array.prototype.filter === \"function\" &&\ntypeof Uint8Array.prototype.filter === \"function\" &&\ntypeof Uint8ClampedArray.prototype.filter === \"function\" &&\ntypeof Int16Array.prototype.filter === \"function\" &&\ntypeof Uint16Array.prototype.filter === \"function\" &&\ntypeof Int32Array.prototype.filter === \"function\" &&\ntypeof Uint32Array.prototype.filter === \"function\" &&\ntypeof Float32Array.prototype.filter === \"function\" &&\ntypeof Float64Array.prototype.filter === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.forEach",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/forEach",
        "exec": "return typeof Int8Array.prototype.forEach === \"function\" &&\ntypeof Uint8Array.prototype.forEach === \"function\" &&\ntypeof Uint8ClampedArray.prototype.forEach === \"function\" &&\ntypeof Int16Array.prototype.forEach === \"function\" &&\ntypeof Uint16Array.prototype.forEach === \"function\" &&\ntypeof Int32Array.prototype.forEach === \"function\" &&\ntypeof Uint32Array.prototype.forEach === \"function\" &&\ntypeof Float32Array.prototype.forEach === \"function\" &&\ntypeof Float64Array.prototype.forEach === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.map",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/map",
        "exec": "return typeof Int8Array.prototype.map === \"function\" &&\ntypeof Uint8Array.prototype.map === \"function\" &&\ntypeof Uint8ClampedArray.prototype.map === \"function\" &&\ntypeof Int16Array.prototype.map === \"function\" &&\ntypeof Uint16Array.prototype.map === \"function\" &&\ntypeof Int32Array.prototype.map === \"function\" &&\ntypeof Uint32Array.prototype.map === \"function\" &&\ntypeof Float32Array.prototype.map === \"function\" &&\ntypeof Float64Array.prototype.map === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.reduce",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/reduce",
        "exec": "return typeof Int8Array.prototype.reduce === \"function\" &&\ntypeof Uint8Array.prototype.reduce === \"function\" &&\ntypeof Uint8ClampedArray.prototype.reduce === \"function\" &&\ntypeof Int16Array.prototype.reduce === \"function\" &&\ntypeof Uint16Array.prototype.reduce === \"function\" &&\ntypeof Int32Array.prototype.reduce === \"function\" &&\ntypeof Uint32Array.prototype.reduce === \"function\" &&\ntypeof Float32Array.prototype.reduce === \"function\" &&\ntypeof Float64Array.prototype.reduce === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.reduceRight",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/reduceRight",
        "exec": "return typeof Int8Array.prototype.reduceRight === \"function\" &&\ntypeof Uint8Array.prototype.reduceRight === \"function\" &&\ntypeof Uint8ClampedArray.prototype.reduceRight === \"function\" &&\ntypeof Int16Array.prototype.reduceRight === \"function\" &&\ntypeof Uint16Array.prototype.reduceRight === \"function\" &&\ntypeof Int32Array.prototype.reduceRight === \"function\" &&\ntypeof Uint32Array.prototype.reduceRight === \"function\" &&\ntypeof Float32Array.prototype.reduceRight === \"function\" &&\ntypeof Float64Array.prototype.reduceRight === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.reverse",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/reverse",
        "exec": "return typeof Int8Array.prototype.reverse === \"function\" &&\ntypeof Uint8Array.prototype.reverse === \"function\" &&\ntypeof Uint8ClampedArray.prototype.reverse === \"function\" &&\ntypeof Int16Array.prototype.reverse === \"function\" &&\ntypeof Uint16Array.prototype.reverse === \"function\" &&\ntypeof Int32Array.prototype.reverse === \"function\" &&\ntypeof Uint32Array.prototype.reverse === \"function\" &&\ntypeof Float32Array.prototype.reverse === \"function\" &&\ntypeof Float64Array.prototype.reverse === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.some",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/some",
        "exec": "return typeof Int8Array.prototype.some === \"function\" &&\ntypeof Uint8Array.prototype.some === \"function\" &&\ntypeof Uint8ClampedArray.prototype.some === \"function\" &&\ntypeof Int16Array.prototype.some === \"function\" &&\ntypeof Uint16Array.prototype.some === \"function\" &&\ntypeof Int32Array.prototype.some === \"function\" &&\ntypeof Uint32Array.prototype.some === \"function\" &&\ntypeof Float32Array.prototype.some === \"function\" &&\ntypeof Float64Array.prototype.some === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.sort",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/sort",
        "exec": "return typeof Int8Array.prototype.sort === \"function\" &&\ntypeof Uint8Array.prototype.sort === \"function\" &&\ntypeof Uint8ClampedArray.prototype.sort === \"function\" &&\ntypeof Int16Array.prototype.sort === \"function\" &&\ntypeof Uint16Array.prototype.sort === \"function\" &&\ntypeof Int32Array.prototype.sort === \"function\" &&\ntypeof Uint32Array.prototype.sort === \"function\" &&\ntypeof Float32Array.prototype.sort === \"function\" &&\ntypeof Float64Array.prototype.sort === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.copyWithin",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/copyWithin",
        "exec": "return typeof Int8Array.prototype.copyWithin === \"function\" &&\ntypeof Uint8Array.prototype.copyWithin === \"function\" &&\ntypeof Uint8ClampedArray.prototype.copyWithin === \"function\" &&\ntypeof Int16Array.prototype.copyWithin === \"function\" &&\ntypeof Uint16Array.prototype.copyWithin === \"function\" &&\ntypeof Int32Array.prototype.copyWithin === \"function\" &&\ntypeof Uint32Array.prototype.copyWithin === \"function\" &&\ntypeof Float32Array.prototype.copyWithin === \"function\" &&\ntypeof Float64Array.prototype.copyWithin === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.find",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/find",
        "exec": "return typeof Int8Array.prototype.find === \"function\" &&\ntypeof Uint8Array.prototype.find === \"function\" &&\ntypeof Uint8ClampedArray.prototype.find === \"function\" &&\ntypeof Int16Array.prototype.find === \"function\" &&\ntypeof Uint16Array.prototype.find === \"function\" &&\ntypeof Int32Array.prototype.find === \"function\" &&\ntypeof Uint32Array.prototype.find === \"function\" &&\ntypeof Float32Array.prototype.find === \"function\" &&\ntypeof Float64Array.prototype.find === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.findIndex",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/findIndex",
        "exec": "return typeof Int8Array.prototype.findIndex === \"function\" &&\ntypeof Uint8Array.prototype.findIndex === \"function\" &&\ntypeof Uint8ClampedArray.prototype.findIndex === \"function\" &&\ntypeof Int16Array.prototype.findIndex === \"function\" &&\ntypeof Uint16Array.prototype.findIndex === \"function\" &&\ntypeof Int32Array.prototype.findIndex === \"function\" &&\ntypeof Uint32Array.prototype.findIndex === \"function\" &&\ntypeof Float32Array.prototype.findIndex === \"function\" &&\ntypeof Float64Array.prototype.findIndex === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.fill",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/fill",
        "exec": "return typeof Int8Array.prototype.fill === \"function\" &&\ntypeof Uint8Array.prototype.fill === \"function\" &&\ntypeof Uint8ClampedArray.prototype.fill === \"function\" &&\ntypeof Int16Array.prototype.fill === \"function\" &&\ntypeof Uint16Array.prototype.fill === \"function\" &&\ntypeof Int32Array.prototype.fill === \"function\" &&\ntypeof Uint32Array.prototype.fill === \"function\" &&\ntypeof Float32Array.prototype.fill === \"function\" &&\ntypeof Float64Array.prototype.fill === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/keys",
        "exec": "return typeof Int8Array.prototype.keys === \"function\" &&\ntypeof Uint8Array.prototype.keys === \"function\" &&\ntypeof Uint8ClampedArray.prototype.keys === \"function\" &&\ntypeof Int16Array.prototype.keys === \"function\" &&\ntypeof Uint16Array.prototype.keys === \"function\" &&\ntypeof Int32Array.prototype.keys === \"function\" &&\ntypeof Uint32Array.prototype.keys === \"function\" &&\ntypeof Float32Array.prototype.keys === \"function\" &&\ntypeof Float64Array.prototype.keys === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.values",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/values",
        "exec": "return typeof Int8Array.prototype.values === \"function\" &&\ntypeof Uint8Array.prototype.values === \"function\" &&\ntypeof Uint8ClampedArray.prototype.values === \"function\" &&\ntypeof Int16Array.prototype.values === \"function\" &&\ntypeof Uint16Array.prototype.values === \"function\" &&\ntypeof Int32Array.prototype.values === \"function\" &&\ntypeof Uint32Array.prototype.values === \"function\" &&\ntypeof Float32Array.prototype.values === \"function\" &&\ntypeof Float64Array.prototype.values === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype.entries",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/entries",
        "exec": "return typeof Int8Array.prototype.entries === \"function\" &&\ntypeof Uint8Array.prototype.entries === \"function\" &&\ntypeof Uint8ClampedArray.prototype.entries === \"function\" &&\ntypeof Int16Array.prototype.entries === \"function\" &&\ntypeof Uint16Array.prototype.entries === \"function\" &&\ntypeof Int32Array.prototype.entries === \"function\" &&\ntypeof Uint32Array.prototype.entries === \"function\" &&\ntypeof Float32Array.prototype.entries === \"function\" &&\ntypeof Float64Array.prototype.entries === \"function\";"
      },
      {
        "name": "%TypedArray%.prototype[Symbol.iterator]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/@@iterator",
        "exec": "return typeof Int8Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Uint8Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Uint8ClampedArray.prototype[Symbol.iterator] === \"function\" &&\ntypeof Int16Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Uint16Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Int32Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Uint32Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Float32Array.prototype[Symbol.iterator] === \"function\" &&\ntypeof Float64Array.prototype[Symbol.iterator] === \"function\";"
      },
      {
        "name": "%TypedArray%[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/@@species",
        "exec": "return typeof Int8Array[Symbol.species] === \"function\" &&\ntypeof Uint8Array[Symbol.species] === \"function\" &&\ntypeof Uint8ClampedArray[Symbol.species] === \"function\" &&\ntypeof Int16Array[Symbol.species] === \"function\" &&\ntypeof Uint16Array[Symbol.species] === \"function\" &&\ntypeof Int32Array[Symbol.species] === \"function\" &&\ntypeof Uint32Array[Symbol.species] === \"function\" &&\ntypeof Float32Array[Symbol.species] === \"function\" &&\ntypeof Float64Array[Symbol.species] === \"function\";"
      }
    ]
  },
  {
    "name": "Map",
    "target": "es6",
    "category": "built-ins",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-map-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var key = {};\nvar map = new Map();\n\nmap.set(key, 123);\n\nreturn map.has(key) && map.get(key) === 123;"
      },
      {
        "name": "constructor arguments",
        "exec": "var key1 = {};\nvar key2 = {};\nvar map = new Map([[key1, 123], [key2, 456]]);\n\nreturn map.has(key1) && map.get(key1) === 123 &&\n       map.has(key2) && map.get(key2) === 456;"
      },
      {
        "name": "constructor requires new",
        "exec": "new Map();\ntry {\n  Map();\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "constructor accepts null",
        "exec": "new Map(null);\nreturn true;"
      },
      {
        "name": "constructor invokes set",
        "exec": "var passed = false;\nvar _set = Map.prototype.set;\n\nMap.prototype.set = function(k, v) {\n  passed = true;\n};\n\nnew Map([ [1, 2] ]);\nMap.prototype.set = _set;\n\nreturn passed;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\ntry {\n  new Map(iter);\n} catch(e){}\nreturn closed;"
      },
      {
        "name": "Map.prototype.set returns this",
        "exec": "var map = new Map();\nreturn map.set(0, 0) === map;"
      },
      {
        "name": "-0 key converts to +0",
        "exec": "var map = new Map();\nmap.set(-0, \"foo\");\nvar k;\nmap.forEach(function (value, key) {\n  k = 1 / key;\n});\nreturn k === Infinity && map.get(+0) === \"foo\";"
      },
      {
        "name": "Map.prototype.size",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/size",
        "exec": "var key = {};\nvar map = new Map();\n\nmap.set(key, 123);\n\nreturn map.size === 1;"
      },
      {
        "name": "Map.prototype.delete",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete",
        "exec": "return typeof Map.prototype.delete === \"function\";"
      },
      {
        "name": "Map.prototype.clear",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/clear",
        "exec": "return typeof Map.prototype.clear === \"function\";"
      },
      {
        "name": "Map.prototype.forEach",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/forEach",
        "exec": "return typeof Map.prototype.forEach === \"function\";"
      },
      {
        "name": "Map.prototype.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/keys",
        "exec": "return typeof Map.prototype.keys === \"function\";"
      },
      {
        "name": "Map.prototype.values",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/values",
        "exec": "return typeof Map.prototype.values === \"function\";"
      },
      {
        "name": "Map.prototype.entries",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/entries",
        "exec": "return typeof Map.prototype.entries === \"function\";"
      },
      {
        "name": "Map.prototype[Symbol.iterator]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/@@iterator",
        "exec": "return typeof Map.prototype[Symbol.iterator] === \"function\";"
      },
      {
        "name": "Map.prototype isn't an instance",
        "exec": "new Map();\nvar obj = {};\ntry {\n  Map.prototype.has(obj);\n}\ncatch(e) {\n  return true;\n}"
      },
      {
        "name": "Map iterator prototype chain",
        "exec": "// Iterator instance\nvar iterator = new Map()[Symbol.iterator]();\n// %MapIteratorPrototype%\nvar proto1 = Object.getPrototypeOf(iterator);\n// %IteratorPrototype%\nvar proto2 = Object.getPrototypeOf(proto1);\n\nreturn proto2.hasOwnProperty(Symbol.iterator) &&\n  !proto1    .hasOwnProperty(Symbol.iterator) &&\n  !iterator  .hasOwnProperty(Symbol.iterator) &&\n  iterator[Symbol.iterator]() === iterator;"
      },
      {
        "name": "Map[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/@@species",
        "exec": "var prop = Object.getOwnPropertyDescriptor(Map, Symbol.species);\nreturn 'get' in prop && Map[Symbol.species] === Map;"
      }
    ]
  },
  {
    "name": "Set",
    "target": "es6",
    "category": "built-ins",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-set-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var obj = {};\nvar set = new Set();\n\nset.add(123);\nset.add(123);\n\nreturn set.has(123);"
      },
      {
        "name": "constructor arguments",
        "exec": "var obj1 = {};\nvar obj2 = {};\nvar set = new Set([obj1, obj2]);\n\nreturn set.has(obj1) && set.has(obj2);"
      },
      {
        "name": "constructor requires new",
        "exec": "new Set();\ntry {\n  Set();\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "constructor accepts null",
        "exec": "new Set(null);\nreturn true;"
      },
      {
        "name": "constructor invokes add",
        "exec": "var passed = false;\nvar _add = Set.prototype.add;\n\nSet.prototype.add = function(v) {\n  passed = true;\n};\n\nnew Set([1]);\nSet.prototype.add = _add;\n\nreturn passed;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\nvar add = Set.prototype.add;\nSet.prototype.add = function(){ throw 0 };\ntry {\n  new Set(iter);\n} catch(e){}\nSet.prototype.add = add;\nreturn closed;"
      },
      {
        "name": "Set.prototype.add returns this",
        "exec": "var set = new Set();\nreturn set.add(0) === set;"
      },
      {
        "name": "-0 key converts to +0",
        "exec": "var set = new Set();\nset.add(-0);\nvar k;\nset.forEach(function (value) {\n  k = 1 / value;\n});\nreturn k === Infinity && set.has(+0);"
      },
      {
        "name": "Set.prototype.size",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/size",
        "exec": "var obj = {};\nvar set = new Set();\n\nset.add(123);\nset.add(123);\nset.add(456);\n\nreturn set.size === 2;"
      },
      {
        "name": "Set.prototype.delete",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/delete",
        "exec": "return typeof Set.prototype.delete === \"function\";"
      },
      {
        "name": "Set.prototype.clear",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/clear",
        "exec": "return typeof Set.prototype.clear === \"function\";"
      },
      {
        "name": "Set.prototype.forEach",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/forEach",
        "exec": "return typeof Set.prototype.forEach === \"function\";"
      },
      {
        "name": "Set.prototype.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/keys",
        "exec": "return typeof Set.prototype.keys === \"function\";"
      },
      {
        "name": "Set.prototype.values",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/values",
        "exec": "return typeof Set.prototype.values === \"function\";"
      },
      {
        "name": "Set.prototype.entries",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/entries",
        "exec": "return typeof Set.prototype.entries === \"function\";"
      },
      {
        "name": "Set.prototype[Symbol.iterator]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/@@iterator",
        "exec": "return typeof Set.prototype[Symbol.iterator] === \"function\";"
      },
      {
        "name": "Set.prototype isn't an instance",
        "exec": "new Set();\nvar obj = {};\ntry {\n  Set.prototype.has(obj);\n}\ncatch(e) {\n  return true;\n}"
      },
      {
        "name": "Set iterator prototype chain",
        "exec": "// Iterator instance\nvar iterator = new Set()[Symbol.iterator]();\n// %SetIteratorPrototype%\nvar proto1 = Object.getPrototypeOf(iterator);\n// %IteratorPrototype%\nvar proto2 = Object.getPrototypeOf(proto1);\n\nreturn proto2.hasOwnProperty(Symbol.iterator) &&\n  !proto1    .hasOwnProperty(Symbol.iterator) &&\n  !iterator  .hasOwnProperty(Symbol.iterator) &&\n  iterator[Symbol.iterator]() === iterator;"
      },
      {
        "name": "Set[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/@@species",
        "exec": "var prop = Object.getOwnPropertyDescriptor(Set, Symbol.species);\nreturn 'get' in prop && Set[Symbol.species] === Set;"
      }
    ]
  },
  {
    "name": "WeakMap",
    "target": "es6",
    "category": "built-ins",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-weakmap-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var key = {};\nvar weakmap = new WeakMap();\n\nweakmap.set(key, 123);\n\nreturn weakmap.has(key) && weakmap.get(key) === 123;"
      },
      {
        "name": "constructor arguments",
        "exec": "var key1 = {};\nvar key2 = {};\nvar weakmap = new WeakMap([[key1, 123], [key2, 456]]);\n\nreturn weakmap.has(key1) && weakmap.get(key1) === 123 &&\n       weakmap.has(key2) && weakmap.get(key2) === 456;"
      },
      {
        "name": "constructor requires new",
        "exec": "new WeakMap();\ntry {\n  WeakMap();\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "constructor accepts null",
        "exec": "new WeakMap(null);\nreturn true;"
      },
      {
        "name": "constructor invokes set",
        "exec": "var passed = false;\nvar _set = WeakMap.prototype.set;\n\nWeakMap.prototype.set = function(k, v) {\n  passed = true;\n};\n\nnew WeakMap([ [{ }, 42] ]);\nWeakMap.prototype.set = _set;\n\nreturn passed;"
      },
      {
        "name": "frozen objects as keys",
        "exec": "var f = Object.freeze({});\nvar m = new WeakMap;\nm.set(f, 42);\nreturn m.get(f) === 42;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\ntry {\n  new WeakMap(iter);\n} catch(e){}\nreturn closed;"
      },
      {
        "name": "WeakMap.prototype.set returns this",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/set#Return_value",
        "exec": "var weakmap = new WeakMap();\nvar key = {};\nreturn weakmap.set(key, 0) === weakmap;"
      },
      {
        "name": "WeakMap.prototype.delete",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/delete",
        "exec": "return typeof WeakMap.prototype.delete === \"function\";"
      },
      {
        "name": "no WeakMap.prototype.clear method",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/clear",
        "exec": "if (!(\"clear\" in WeakMap.prototype)) {\n  return true;\n}\nvar m = new WeakMap();\nvar key = {};\nm.set(key, 2);\nm.clear();\nreturn m.has(key);"
      },
      {
        "name": ".has, .get and .delete methods accept primitives",
        "exec": "var m = new WeakMap;\nreturn m.has(1) === false\n  && m.get(1) === void undefined\n  && m.delete(1) === false;"
      },
      {
        "name": "WeakMap.prototype isn't an instance",
        "exec": "new WeakMap();\nvar obj = {};\ntry {\n  WeakMap.prototype.has(obj);\n}\ncatch(e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "WeakSet",
    "target": "es6",
    "category": "built-ins",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-weakset-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var obj1 = {};\nvar weakset = new WeakSet();\n\nweakset.add(obj1);\nweakset.add(obj1);\n\nreturn weakset.has(obj1);"
      },
      {
        "name": "constructor arguments",
        "exec": "var obj1 = {}, obj2 = {};\nvar weakset = new WeakSet([obj1, obj2]);\n\nreturn weakset.has(obj1) && weakset.has(obj2);"
      },
      {
        "name": "constructor requires new",
        "exec": "new WeakSet();\ntry {\n  WeakSet();\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "constructor accepts null",
        "exec": "new WeakSet(null);\nreturn true;"
      },
      {
        "name": "constructor invokes add",
        "exec": "var passed = false;\nvar _add = WeakSet.prototype.add;\n\nWeakSet.prototype.add = function(v) {\n  passed = true;\n};\n\nnew WeakSet([ { } ]);\nWeakSet.prototype.add = _add;\n\nreturn passed;"
      },
      {
        "name": "iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\ntry {\n  new WeakSet(iter);\n} catch(e){}\nreturn closed;"
      },
      {
        "name": "WeakSet.prototype.add returns this",
        "exec": "var weakset = new WeakSet();\nvar obj = {};\nreturn weakset.add(obj) === weakset;"
      },
      {
        "name": "WeakSet.prototype.delete",
        "exec": "return typeof WeakSet.prototype.delete === \"function\";"
      },
      {
        "name": "no WeakSet.prototype.clear method",
        "exec": "if (!(\"clear\" in WeakSet.prototype)) {\n  return true;\n}\nvar s = new WeakSet();\nvar key = {};\ns.add(key);\ns.clear();\nreturn s.has(key);"
      },
      {
        "name": ".has and .delete methods accept primitives",
        "exec": "var s = new WeakSet;\nreturn s.has(1) === false\n  && s.delete(1) === false;"
      },
      {
        "name": "WeakSet.prototype isn't an instance",
        "exec": "new WeakSet();\nvar obj = {};\ntry {\n  WeakSet.prototype.has(obj);\n}\ncatch(e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "Proxy",
    "target": "es6",
    "category": "built-ins",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy",
    "subtests": [
      {
        "name": "constructor requires new",
        "exec": "new Proxy({}, {});\ntry {\n  Proxy({}, {});\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "no \"prototype\" property",
        "exec": "new Proxy({}, {});\nreturn !Proxy.hasOwnProperty('prototype');"
      },
      {
        "name": "\"get\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/get",
        "exec": "var proxied = { };\nvar proxy = new Proxy(proxied, {\n  get: function (t, k, r) {\n    return t === proxied && k === \"foo\" && r === proxy && 5;\n  }\n});\nreturn proxy.foo === 5;"
      },
      {
        "name": "\"get\" handler, instances of proxies",
        "exec": "var proxied = { };\nvar proxy = Object.create(new Proxy(proxied, {\n  get: function (t, k, r) {\n    return t === proxied && k === \"foo\" && r === proxy && 5;\n  }\n}));\nreturn proxy.foo === 5;"
      },
      {
        "name": "\"get\" handler invariants",
        "exec": "var passed = false;\nvar proxied = { };\nvar proxy = new Proxy(proxied, {\n  get: function () {\n    passed = true;\n    return 4;\n  }\n});\n// The value reported for a property must be the same as the value of the corresponding\n// target object property if the target object property is a non-writable,\n// non-configurable own data property.\nObject.defineProperty(proxied, \"foo\", { value: 5, enumerable: true });\ntry {\n  proxy.foo;\n  return false;\n}\ncatch(e) {}\n// The value reported for a property must be undefined if the corresponding target\n// object property is a non-configurable own accessor property that has undefined\n// as its [[Get]] attribute.\nObject.defineProperty(proxied, \"bar\",\n  { set: function(){}, enumerable: true });\ntry {\n  proxy.bar;\n  return false;\n}\ncatch(e) {}\nreturn passed;"
      },
      {
        "name": "\"set\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/set",
        "exec": "var proxied = { };\nvar passed = false;\nvar proxy = new Proxy(proxied, {\n  set: function (t, k, v, r) {\n    passed = t === proxied && k + v === \"foobar\" && r === proxy;\n  }\n});\nproxy.foo = \"bar\";\nreturn passed;"
      },
      {
        "name": "\"set\" handler, instances of proxies",
        "exec": "var proxied = { };\nvar passed = false;\nvar proxy = Object.create(new Proxy(proxied, {\n  set: function (t, k, v, r) {\n    passed = t === proxied && k + v === \"foobar\" && r === proxy;\n  }\n}));\nproxy.foo = \"bar\";\nreturn passed;"
      },
      {
        "name": "\"set\" handler invariants",
        "exec": "var passed = false;\nnew Proxy({},{});\n// Cannot change the value of a property to be different from the value of\n// the corresponding target object if the corresponding target object\n// property is a non-writable, non-configurable own data property.\nvar proxied = {};\nvar proxy = new Proxy(proxied, {\n  set: function () {\n    passed = true;\n    return true;\n  }\n});\nObject.defineProperty(proxied, \"foo\", { value: 2, enumerable: true });\nproxy.foo = 2;\ntry {\n  proxy.foo = 4;\n  return false;\n} catch(e) {}\n// Cannot set the value of a property if the corresponding target\n// object property is a non-configurable own accessor property\n// that has undefined as its [[Set]] attribute.\nObject.defineProperty(proxied, \"bar\",\n  { get: function(){}, enumerable: true });\ntry {\n  proxy.bar = 2;\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"has\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/has",
        "exec": "var proxied = {};\nvar passed = false;\n\"foo\" in new Proxy(proxied, {\n  has: function (t, k) {\n    passed = t === proxied && k === \"foo\";\n  }\n});\nreturn passed;"
      },
      {
        "name": "\"has\" handler, instances of proxies",
        "exec": "var proxied = {};\nvar passed = false;\n\"foo\" in Object.create(new Proxy(proxied, {\n  has: function (t, k) {\n    passed = t === proxied && k === \"foo\";\n  }\n}));\nreturn passed;"
      },
      {
        "name": "\"has\" handler invariants",
        "exec": "var passed = false;\nnew Proxy({},{});\n// A property cannot be reported as non-existent, if it exists as a\n// non-configurable own property of the target object.\nvar proxied = {};\nvar proxy = new Proxy(proxied, {\n  has: function () {\n    passed = true;\n    return false;\n  }\n});\nObject.defineProperty(proxied, \"foo\", { value: 2, writable: true, enumerable: true });\ntry {\n  'foo' in proxy;\n  return false;\n} catch(e) {}\n// A property cannot be reported as non-existent, if it exists as an\n// own property of the target object and the target object is not extensible.\nproxied.bar = 2;\nObject.preventExtensions(proxied);\ntry {\n  'bar' in proxy;\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"deleteProperty\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty",
        "exec": "var proxied = {};\nvar passed = false;\ndelete new Proxy(proxied, {\n  deleteProperty: function (t, k) {\n    passed = t === proxied && k === \"foo\";\n  }\n}).foo;\nreturn passed;"
      },
      {
        "name": "\"deleteProperty\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\n// A property cannot be reported as deleted, if it exists as a non-configurable\n// own property of the target object.\nvar proxied = {};\nObject.defineProperty(proxied, \"foo\", { value: 2, writable: true, enumerable: true });\ntry {\n  delete new Proxy(proxied, {\n    deleteProperty: function () {\n      passed = true;\n      return true;\n    }\n  }).foo;\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"getOwnPropertyDescriptor\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/getOwnPropertyDescriptor",
        "exec": "var proxied = {};\nvar fakeDesc = { value: \"foo\", configurable: true };\nvar returnedDesc = Object.getOwnPropertyDescriptor(\n  new Proxy(proxied, {\n    getOwnPropertyDescriptor: function (t, k) {\n      return t === proxied && k === \"foo\" && fakeDesc;\n    }\n  }),\n  \"foo\"\n);\nreturn (returnedDesc.value     === fakeDesc.value\n  && returnedDesc.configurable === fakeDesc.configurable\n  && returnedDesc.writable     === false\n  && returnedDesc.enumerable   === false);"
      },
      {
        "name": "\"getOwnPropertyDescriptor\" handler invariants",
        "exec": "var passed = false;\nnew Proxy({},{});\n// A property cannot be reported as non-existent, if it exists as a non-configurable\n// own property of the target object.\nvar proxied = {};\nvar proxy = new Proxy(proxied, {\n  getOwnPropertyDescriptor: function () {\n    passed = true;\n    return undefined;\n  }\n});\nObject.defineProperty(proxied, \"foo\", { value: 2, writable: true, enumerable: true });\ntry {\n  Object.getOwnPropertyDescriptor(proxy, \"foo\");\n  return false;\n} catch(e) {}\n// A property cannot be reported as non-existent, if it exists as an own property\n// of the target object and the target object is not extensible.\nproxied.bar = 3;\nObject.preventExtensions(proxied);\ntry {\n  Object.getOwnPropertyDescriptor(proxy, \"bar\");\n  return false;\n} catch(e) {}\n// A property cannot be reported as existent, if it does not exists as an own property\n// of the target object and the target object is not extensible.\ntry {\n  Object.getOwnPropertyDescriptor(new Proxy(proxied, {\n    getOwnPropertyDescriptor: function() {\n      return { value: 2, configurable: true, writable: true, enumerable: true };\n    }}), \"baz\");\n  return false;\n} catch(e) {}\n// A property cannot be reported as non-configurable, if it does not exists as an own\n// property of the target object or if it exists as a configurable own property of\n// the target object.\ntry {\n  Object.getOwnPropertyDescriptor(new Proxy({}, {\n    getOwnPropertyDescriptor: function() {\n      return { value: 2, configurable: false, writable: true, enumerable: true };\n    }}), \"baz\");\n  return false;\n} catch(e) {}\ntry {\n  Object.getOwnPropertyDescriptor(new Proxy({baz:1}, {\n    getOwnPropertyDescriptor: function() {\n      return { value: 1, configurable: false, writable: true, enumerable: true };\n    }}), \"baz\");\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"defineProperty\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/defineProperty",
        "exec": "var proxied = {};\nvar passed = false;\nObject.defineProperty(\n  new Proxy(proxied, {\n    defineProperty: function (t, k, d) {\n      passed = t === proxied && k === \"foo\" && d.value === 5;\n      return true;\n    }\n  }),\n  \"foo\",\n  { value: 5, configurable: true }\n);\nreturn passed;"
      },
      {
        "name": "\"defineProperty\" handler invariants",
        "exec": "var passed = false;\nnew Proxy({},{});\n// A property cannot be added, if the target object is not extensible.\nvar proxied = Object.preventExtensions({});\nvar proxy = new Proxy(proxied, {\n  defineProperty: function() {\n    passed = true;\n    return true;\n  }\n});\ntry {\n  Object.defineProperty(proxy, \"foo\", { value: 2 });\n  return false;\n} catch(e) {}\n// A property cannot be non-configurable, unless there exists a corresponding\n// non-configurable own property of the target object.\ntry {\n  Object.defineProperty(\n    new Proxy({ bar: true }, {\n      defineProperty: function () {\n        return true;\n      }\n    }),\n    \"bar\",\n    { value: 5, configurable: false, writable: true, enumerable: true }\n  );\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"getPrototypeOf\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/getPrototypeOf",
        "exec": "var proxied = {};\nvar fakeProto = {};\nvar proxy = new Proxy(proxied, {\n  getPrototypeOf: function (t) {\n    return t === proxied && fakeProto;\n  }\n});\nreturn Object.getPrototypeOf(proxy) === fakeProto;"
      },
      {
        "name": "\"getPrototypeOf\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\n// If the target object is not extensible, [[GetPrototypeOf]] applied to the proxy object\n// must return the same value as [[GetPrototypeOf]] applied to the proxy object's target object.\ntry {\n  Object.getPrototypeOf(new Proxy(Object.preventExtensions({}), {\n    getPrototypeOf: function () {\n      passed = true;\n      return {};\n    }\n  }));\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"setPrototypeOf\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/setPrototypeOf",
        "exec": "var proxied = {};\nvar newProto = {};\nvar passed = false;\nObject.setPrototypeOf(\n  new Proxy(proxied, {\n    setPrototypeOf: function (t, p) {\n      passed = t === proxied && p === newProto;\n      return true;\n    }\n  }),\n  newProto\n);\nreturn passed;"
      },
      {
        "name": "\"setPrototypeOf\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\nObject.setPrototypeOf({},{});\n// If the target object is not extensible, the argument value must be the\n// same as the result of [[GetPrototypeOf]] applied to target object.\ntry {\n  Object.setPrototypeOf(\n    new Proxy(Object.preventExtensions({}), {\n      setPrototypeOf: function () {\n        passed = true;\n        return true;\n      }\n    }),{});\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"isExtensible\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/isExtensible",
        "exec": "var proxied = {};\nvar passed = false;\nObject.isExtensible(\n  new Proxy(proxied, {\n    isExtensible: function (t) {\n      passed = t === proxied; return true;\n    }\n  })\n);\nreturn passed;"
      },
      {
        "name": "\"isExtensible\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\n// [[IsExtensible]] applied to the proxy object must return the same value\n// as [[IsExtensible]] applied to the proxy object's target object with the same argument.\ntry {\n  Object.isExtensible(new Proxy({}, {\n    isExtensible: function (t) {\n      passed = true;\n      return false;\n    }\n  }));\n  return false;\n} catch(e) {}\ntry {\n  Object.isExtensible(new Proxy(Object.preventExtensions({}), {\n    isExtensible: function (t) {\n      return true;\n    }\n  }));\n  return false;\n} catch(e) {}\nreturn true;"
      },
      {
        "name": "\"preventExtensions\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/preventExtensions",
        "exec": "var proxied = {};\nvar passed = false;\nObject.preventExtensions(\n  new Proxy(proxied, {\n    preventExtensions: function (t) {\n      passed = t === proxied;\n      return Object.preventExtensions(proxied);\n    }\n  })\n);\nreturn passed;"
      },
      {
        "name": "\"preventExtensions\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\n// [[PreventExtensions]] applied to the proxy object only returns true\n// if [[IsExtensible]] applied to the proxy object's target object is false.\ntry {\n  Object.preventExtensions(new Proxy({}, {\n    preventExtensions: function () {\n      passed = true;\n      return true;\n    }\n  }));\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"ownKeys\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys",
        "exec": "var proxied = {};\nvar passed = false;\nObject.keys(\n  new Proxy(proxied, {\n    ownKeys: function (t) {\n      passed = t === proxied; return [];\n    }\n  })\n);\nreturn passed;"
      },
      {
        "name": "\"ownKeys\" handler invariant",
        "exec": "var passed = false;\nnew Proxy({},{});\n// The Type of each result List element is either String or Symbol.\ntry {\n  Object.keys(new Proxy({}, {\n    ownKeys: function () {\n      passed = true;\n      return [2];\n    }}));\n  return false;\n} catch(e) {}\n// The result List must contain the keys of all non-configurable own properties of the target object.\nvar proxied = {};\nObject.defineProperty(proxied, \"foo\", { value: 2, writable: true, enumerable: true });\ntry {\n  Object.keys(new Proxy(proxied, {\n    ownKeys: function () {\n      return [];\n    }}));\n  return false;\n} catch(e) {}\n// If the target object is not extensible, then the result List must contain all the keys\n// of the own properties of the target object and no other values.\ntry {\n  Object.keys(new Proxy(Object.preventExtensions({b:1}), {\n    ownKeys: function () {\n      return ['a'];\n    }}));\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"apply\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply",
        "exec": "var proxied = function(){};\nvar passed = false;\nvar host = {\n  method: new Proxy(proxied, {\n    apply: function (t, thisArg, args) {\n      passed = t === proxied && thisArg === host && args + \"\" === \"foo,bar\";\n    }\n  })\n};\nhost.method(\"foo\", \"bar\");\nreturn passed;"
      },
      {
        "name": "\"apply\" handler invariant",
        "exec": "var passed = false;\nnew Proxy(function(){}, {\n    apply: function () { passed = true; }\n})();\n// A Proxy exotic object only has a [[Call]] internal method if the\n// initial value of its [[ProxyTarget]] internal slot is an object\n// that has a [[Call]] internal method.\ntry {\n  new Proxy({}, {\n    apply: function () {}\n  })();\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "\"construct\" handler",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/construct",
        "exec": "var proxied = function(){};\nvar passed = false;\nnew new Proxy(proxied, {\n  construct: function (t, args) {\n    passed = t === proxied && args + \"\" === \"foo,bar\";\n    return {};\n  }\n})(\"foo\",\"bar\");\nreturn passed;"
      },
      {
        "name": "\"construct\" handler invariants",
        "exec": "var passed = false;\nnew Proxy({},{});\n// A Proxy exotic object only has a [[Construct]] internal method if the\n// initial value of its [[ProxyTarget]] internal slot is an object\n// that has a [[Construct]] internal method.\ntry {\n  new new Proxy({}, {\n    construct: function (t, args) {\n      return {};\n    }\n  })();\n  return false;\n} catch(e) {}\n// The result of [[Construct]] must be an Object.\ntry {\n  new new Proxy(function(){}, {\n    construct: function (t, args) {\n      passed = true;\n      return 5;\n    }\n  })();\n  return false;\n} catch(e) {}\nreturn passed;"
      },
      {
        "name": "Proxy.revocable",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/revocable",
        "exec": "var obj = Proxy.revocable({}, { get: function() { return 5; } });\nvar passed = (obj.proxy.foo === 5);\nobj.revoke();\ntry {\n  obj.proxy.foo;\n} catch(e) {\n  passed &= e instanceof TypeError;\n}\nreturn passed;"
      },
      {
        "name": "Array.isArray support",
        "exec": "return Array.isArray(new Proxy([], {}));"
      },
      {
        "name": "JSON.stringify support",
        "exec": "return JSON.stringify(new Proxy(['foo'], {})) === '[\"foo\"]';"
      }
    ]
  },
  {
    "name": "Reflect",
    "target": "es6",
    "category": "built-ins",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-reflection",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect",
    "subtests": [
      {
        "name": "Reflect.get",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/get",
        "exec": "return Reflect.get({ qux: 987 }, \"qux\") === 987;"
      },
      {
        "name": "Reflect.set",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/set",
        "exec": "var obj = {};\nReflect.set(obj, \"quux\", 654);\nreturn obj.quux === 654;"
      },
      {
        "name": "Reflect.has",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/has",
        "exec": "return Reflect.has({ qux: 987 }, \"qux\");"
      },
      {
        "name": "Reflect.deleteProperty",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/deleteProperty",
        "exec": "var obj = { bar: 456 };\nReflect.deleteProperty(obj, \"bar\");\nreturn !(\"bar\" in obj);"
      },
      {
        "name": "Reflect.getOwnPropertyDescriptor",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/getOwnPropertyDescriptor",
        "exec": "var obj = { baz: 789 };\nvar desc = Reflect.getOwnPropertyDescriptor(obj, \"baz\");\nreturn desc.value === 789 &&\n  desc.configurable && desc.writable && desc.enumerable;"
      },
      {
        "name": "Reflect.defineProperty",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/defineProperty",
        "exec": "var obj = {};\nReflect.defineProperty(obj, \"foo\", { value: 123 });\nreturn obj.foo === 123 &&\n  Reflect.defineProperty(Object.freeze({}), \"foo\", { value: 123 }) === false;"
      },
      {
        "name": "Reflect.getPrototypeOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/getPrototypeOf",
        "exec": "return Reflect.getPrototypeOf([]) === Array.prototype;"
      },
      {
        "name": "Reflect.setPrototypeOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/setPrototypeOf",
        "exec": "var obj = {};\nReflect.setPrototypeOf(obj, Array.prototype);\nreturn obj instanceof Array;"
      },
      {
        "name": "Reflect.isExtensible",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/isExtensible",
        "exec": "return Reflect.isExtensible({}) &&\n  !Reflect.isExtensible(Object.preventExtensions({}));"
      },
      {
        "name": "Reflect.preventExtensions",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/preventExtensions",
        "exec": "var obj = {};\nReflect.preventExtensions(obj);\nreturn !Object.isExtensible(obj);"
      },
      {
        "name": "Reflect.ownKeys, string keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/ownKeys",
        "exec": "var obj = Object.create({ C: true });\nobj.A = true;\nObject.defineProperty(obj, 'B', { value: true, enumerable: false });\n\nreturn Reflect.ownKeys(obj).sort() + '' === \"A,B\";"
      },
      {
        "name": "Reflect.ownKeys, symbol keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/ownKeys",
        "exec": "var s1 = Symbol(), s2 = Symbol(), s3 = Symbol();\nvar proto = {};\nproto[s1] = true;\nvar obj = Object.create(proto);\nobj[s2] = true;\nObject.defineProperty(obj, s3, { value: true, enumerable: false });\n\nvar keys = Reflect.ownKeys(obj);\nreturn keys.indexOf(s2) >-1 && keys.indexOf(s3) >-1 && keys.length === 2;"
      },
      {
        "name": "Reflect.apply",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/apply",
        "exec": "return Reflect.apply(Array.prototype.push, [1,2], [3,4,5]) === 5;"
      },
      {
        "name": "Reflect.construct",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/construct",
        "exec": "return Reflect.construct(function(a, b, c) {\n  this.qux = a + b + c;\n}, [\"foo\", \"bar\", \"baz\"]).qux === \"foobarbaz\";"
      },
      {
        "name": "Reflect.construct sets new.target meta-property",
        "exec": "return Reflect.construct(function(a, b, c) {\n  if (new.target === Object) {\n    this.qux = a + b + c;\n  }\n}, [\"foo\", \"bar\", \"baz\"], Object).qux === \"foobarbaz\";"
      },
      {
        "name": "Reflect.construct creates instances from third argument",
        "exec": "function F(){}\nvar obj = Reflect.construct(function(){ this.y = 1; }, [], F);\nreturn obj.y === 1 && obj instanceof F;"
      },
      {
        "name": "Reflect.construct, Array subclassing",
        "exec": "function F(){}\nvar obj = Reflect.construct(Array, [], F);\nobj[2] = 'foo';\nreturn obj.length === 3 && obj instanceof F;"
      },
      {
        "name": "Reflect.construct, RegExp subclassing",
        "exec": "function F(){}\nvar obj = Reflect.construct(RegExp, [\"baz\",\"g\"], F);\nreturn RegExp.prototype.exec.call(obj, \"foobarbaz\")[0] === \"baz\"\n  && obj.lastIndex === 9 && obj instanceof F;"
      },
      {
        "name": "Reflect.construct, Function subclassing",
        "exec": "function F(){}\nvar obj = Reflect.construct(Function, [\"return 2\"], F);\nreturn obj() === 2 && obj instanceof F;"
      },
      {
        "name": "Reflect.construct, Promise subclassing",
        "exec": "function F(){}\nvar p1 = Reflect.construct(Promise,[function(resolve, reject) { resolve(\"foo\"); }], F);\nvar p2 = Reflect.construct(Promise,[function(resolve, reject) { reject(\"quux\"); }], F);\nvar score = +(p1 instanceof F && p2 instanceof F);\n\nfunction thenFn(result)  { score += (result === \"foo\");  check(); }\nfunction catchFn(result) { score += (result === \"quux\"); check(); }\nfunction shouldNotRun(result)  { score = -Infinity;   }\n\np1.then = p2.then = Promise.prototype.then;\np1.catch = p2.catch = Promise.prototype.catch;\n\np1.then(thenFn, shouldNotRun);\np2.then(shouldNotRun, catchFn);\np1.catch(shouldNotRun);\np2.catch(catchFn);\n\nfunction check() {\n  if (score === 4) asyncTestPassed();\n}"
      }
    ]
  },
  {
    "name": "Promise",
    "target": "es6",
    "category": "built-ins",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-promise-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise",
    "subtests": [
      {
        "name": "basic functionality",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise",
        "exec": "var p1 = new Promise(function(resolve, reject) { resolve(\"foo\"); });\nvar p2 = new Promise(function(resolve, reject) { reject(\"quux\"); });\nvar score = 0;\n\nfunction thenFn(result)  { score += (result === \"foo\");  check(); }\nfunction catchFn(result) { score += (result === \"quux\"); check(); }\nfunction shouldNotRun(result)  { score = -Infinity;   }\n\np1.then(thenFn, shouldNotRun);\np2.then(shouldNotRun, catchFn);\np1.catch(shouldNotRun);\np2.catch(catchFn);\n\np1.then(function() {\n  // Promise.prototype.then() should return a new Promise\n  score += p1.then() !== p1;\n  check();\n});\n\nfunction check() {\n  if (score === 4) asyncTestPassed();\n}"
      },
      {
        "name": "constructor requires new",
        "exec": "new Promise(function(){});\ntry {\n  Promise(function(){});\n  return false;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "Promise.prototype isn't an instance",
        "exec": "new Promise(function(){});\ntry {\n  Promise.prototype.then(function(){});\n} catch (e) {\n  return true;\n}"
      },
      {
        "name": "Promise.all",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all",
        "exec": "var fulfills = Promise.all([\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"foo\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"bar\"); })\n]);\nvar rejects = Promise.all([\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"baz\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"qux\"); })\n]);\nvar score = 0;\nfulfills.then(function(result) { score += (result + \"\" === \"foo,bar\"); check(); });\nrejects.catch(function(result) { score += (result === \"qux\"); check(); });\n\nfunction check() {\n  if (score === 2) asyncTestPassed();\n}"
      },
      {
        "name": "Promise.all, generic iterables",
        "exec": "var fulfills = Promise.all(global.__createIterableObject([\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"foo\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"bar\"); })\n]));\nvar rejects = Promise.all(global.__createIterableObject([\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"baz\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"qux\"); })\n]));\nvar score = 0;\nfulfills.then(function(result) { score += (result + \"\" === \"foo,bar\"); check(); });\nrejects.catch(function(result) { score += (result === \"qux\"); check(); });\n\nfunction check() {\n  if (score === 2) asyncTestPassed();\n}"
      },
      {
        "name": "Promise.race",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/race",
        "exec": "var fulfills = Promise.race([\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"foo\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"bar\"); })\n]);\nvar rejects = Promise.race([\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"baz\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"qux\"); })\n]);\nvar score = 0;\nfulfills.then(function(result) { score += (result === \"foo\"); check(); });\nrejects.catch(function(result) { score += (result === \"baz\"); check(); });\n\nfunction check() {\n  if (score === 2) asyncTestPassed();\n}"
      },
      {
        "name": "Promise.race, generic iterables",
        "exec": "var fulfills = Promise.race(global.__createIterableObject([\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"foo\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"bar\"); })\n]));\nvar rejects = Promise.race(global.__createIterableObject([\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"baz\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"qux\"); })\n]));\nvar score = 0;\nfulfills.then(function(result) { score += (result === \"foo\"); check(); });\nrejects.catch(function(result) { score += (result === \"baz\"); check(); });\n\nfunction check() {\n  if (score === 2) asyncTestPassed();\n}"
      },
      {
        "name": "Promise[Symbol.species]",
        "exec": "var prop = Object.getOwnPropertyDescriptor(Promise, Symbol.species);\nreturn 'get' in prop && Promise[Symbol.species] === Promise;"
      }
    ]
  },
  {
    "name": "Symbol",
    "target": "es6",
    "category": "built-ins",
    "significance": "large",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-symbol-constructor",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var object = {};\nvar symbol = Symbol();\nvar value = {};\nobject[symbol] = value;\nreturn object[symbol] === value;"
      },
      {
        "name": "typeof support",
        "exec": "return typeof Symbol() === \"symbol\";"
      },
      {
        "name": "symbol keys are hidden to pre-ES6 code",
        "exec": "var object = {};\nvar symbol = Symbol();\nobject[symbol] = 1;\n\nfor (var x in object){}\nvar passed = !x;\n\nif (Object.keys && Object.getOwnPropertyNames) {\n  passed &= Object.keys(object).length === 0\n    && Object.getOwnPropertyNames(object).length === 0;\n}\n\nreturn passed;"
      },
      {
        "name": "Object.defineProperty support",
        "exec": "var object = {};\nvar symbol = Symbol();\nvar value = {};\n\nif (Object.defineProperty) {\n  Object.defineProperty(object, symbol, { value: value });\n  return object[symbol] === value;\n}\n\nreturn passed;"
      },
      {
        "name": "symbols inherit from Symbol.prototype",
        "exec": "var symbol = Symbol();\nvar passed = symbol.foo === void undefined;\nSymbol.prototype.foo = 2;\npassed &= symbol.foo === 2;\ndelete Symbol.prototype.foo;\nreturn passed;"
      },
      {
        "name": "cannot coerce to string or number",
        "exec": "var symbol = Symbol();\n\ntry {\n  symbol + \"\";\n  return false;\n}\ncatch(e) {}\n\ntry {\n  symbol + 0;\n  return false;\n} catch(e) {}\n\nreturn true;"
      },
      {
        "name": "can convert with String()",
        "exec": "return String(Symbol(\"foo\")) === \"Symbol(foo)\";"
      },
      {
        "name": "new Symbol() throws",
        "exec": "var symbol = Symbol();\ntry {\n  new Symbol();\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "Object(symbol)",
        "exec": "var symbol = Symbol();\nvar symbolObject = Object(symbol);\n\nreturn typeof symbolObject === \"object\" &&\n  symbolObject instanceof Symbol &&\n  symbolObject == symbol && // eslint-disable-line eqeqeq\n  symbolObject !== symbol &&\n  symbolObject.valueOf() === symbol;"
      },
      {
        "name": "JSON.stringify ignores symbol primitives",
        "exec": "var object = { foo: Symbol() };\nobject[Symbol()] = 1;\nvar array = [Symbol()];\nreturn JSON.stringify(object) === '{}' && JSON.stringify(array) === '[null]' && JSON.stringify(Symbol()) === void undefined;"
      },
      {
        "name": "JSON.stringify ignores symbol objects",
        "exec": "var testSymbolObject = function (sym) {\n  var object = { foo: sym };\n  try {\n    // some browsers throw a TypeError when setting symbol object keys.\n    // this isn't part of this test, so, ignore it if so.\n    object[sym] = 1;\n  } catch (e) {} // some browsers throw a TypeError when setting symbol object keys.\n  var array = [sym];\n  return JSON.stringify(object) === '{\"foo\":{}}' && JSON.stringify(array) === '[{}]' && JSON.stringify(sym) === '{}';\n};\nvar objSym = Object(Symbol());\nvar symNoToJSON = Object(Symbol());\nObject.defineProperty(symNoToJSON, 'toJSON', { enumerable: false, value: null }); // ensure it overrides the prototype, but is not callable\nreturn testSymbolObject(objSym) && testSymbolObject(symNoToJSON);"
      },
      {
        "name": "global symbol registry",
        "exec": "var symbol = Symbol.for('foo');\nreturn Symbol.for('foo') === symbol &&\n   Symbol.keyFor(symbol) === 'foo';"
      }
    ]
  },
  {
    "name": "well-known symbols",
    "target": "es6",
    "category": "built-ins",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-well-known-symbols",
    "subtests": [
      {
        "name": "Symbol.hasInstance",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/hasInstance",
        "exec": "var passed = false;\nvar obj = { foo: true };\nvar C = function(){};\nObject.defineProperty(C, Symbol.hasInstance, {\n  value: function(inst) { passed = inst.foo; return false; }\n});\nobj instanceof C;\nreturn passed;"
      },
      {
        "name": "Symbol.isConcatSpreadable, non-spreadable array",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/isConcatSpreadable",
        "exec": "var a = [], b = [];\nb[Symbol.isConcatSpreadable] = false;\na = a.concat(b);\nreturn a[0] === b;"
      },
      {
        "name": "Symbol.isConcatSpreadable, spreadable object with poisoned getter",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/isConcatSpreadable",
        "exec": "if (typeof Symbol !== 'function' || !Symbol.isConcatSpreadable) {\n  return null;\n}\nvar spreadableHasPoisonedIndex = { length: Math.pow(2, 53) - 1 };\nspreadableHasPoisonedIndex[Symbol.isConcatSpreadable] = true;\nObject.defineProperty(spreadableHasPoisonedIndex, 0, {\n  get: function () { throw new SyntaxError(); }\n});\ntry {\n  [].concat(spreadableHasPoisonedIndex);\n  return false;\n} catch (e) {\n  return !!e && e.name === 'SyntaxError';\n}"
      },
      {
        "name": "Symbol.iterator, existence",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/iterator",
        "exec": "return \"iterator\" in Symbol;"
      },
      {
        "name": "Symbol.iterator, arguments object",
        "exec": "return (function() {\n  return typeof arguments[Symbol.iterator] === 'function'\n    && Object.hasOwnProperty.call(arguments, Symbol.iterator);\n}());"
      },
      {
        "name": "Symbol.species, existence",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/species",
        "exec": "return \"species\" in Symbol;"
      },
      {
        "name": "Symbol.species, Array.prototype.concat",
        "exec": "var obj = [];\nobj.constructor = {};\nobj.constructor[Symbol.species] = function() {\n    return { foo: 1 };\n};\nreturn Array.prototype.concat.call(obj, []).foo === 1;"
      },
      {
        "name": "Symbol.species, Array.prototype.filter",
        "exec": "var obj = [];\nobj.constructor = {};\nobj.constructor[Symbol.species] = function() {\n    return { foo: 1 };\n};\nreturn Array.prototype.filter.call(obj, Boolean).foo === 1;"
      },
      {
        "name": "Symbol.species, Array.prototype.map",
        "exec": "var obj = [];\nobj.constructor = {};\nobj.constructor[Symbol.species] = function() {\n    return { foo: 1 };\n};\nreturn Array.prototype.map.call(obj, Boolean).foo === 1;"
      },
      {
        "name": "Symbol.species, Array.prototype.slice",
        "exec": "var obj = [];\nobj.constructor = {};\nobj.constructor[Symbol.species] = function() {\n    return { foo: 1 };\n};\nreturn Array.prototype.slice.call(obj, 0).foo === 1;"
      },
      {
        "name": "Symbol.species, Array.prototype.splice",
        "exec": "var obj = [];\nobj.constructor = {};\nobj.constructor[Symbol.species] = function() {\n    return { foo: 1 };\n};\nreturn Array.prototype.splice.call(obj, 0).foo === 1;"
      },
      {
        "name": "Symbol.species, RegExp.prototype[Symbol.split]",
        "exec": "var passed = false;\nvar obj = { constructor: {} };\nobj[Symbol.split] = RegExp.prototype[Symbol.split];\nobj.constructor[Symbol.species] = function() {\n  passed = true;\n  return /./;\n};\n\"\".split(obj);\nreturn passed;"
      },
      {
        "name": "Symbol.species, Promise.prototype.then",
        "exec": "var promise      = new Promise(function(resolve){ resolve(42); });\nvar FakePromise1 = promise.constructor = function(exec){ exec(function(){}, function(){}); };\nvar FakePromise2 = function(exec){ exec(function(){}, function(){}); };\nObject.defineProperty(FakePromise1, Symbol.species, {value: FakePromise2});\nreturn promise.then(function(){}) instanceof FakePromise2;"
      },
      {
        "name": "Symbol.replace",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/replace",
        "exec": "var O = {};\nO[Symbol.replace] = function(){\n  return 42;\n};\nreturn ''.replace(O) === 42;"
      },
      {
        "name": "Symbol.search",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/search",
        "exec": "var O = {};\nO[Symbol.search] = function(){\n  return 42;\n};\nreturn ''.search(O) === 42;"
      },
      {
        "name": "Symbol.split",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/split",
        "exec": "var O = {};\nO[Symbol.split] = function(){\n  return 42;\n};\nreturn ''.split(O) === 42;"
      },
      {
        "name": "Symbol.match",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/match",
        "exec": "var O = {};\nO[Symbol.match] = function(){\n  return 42;\n};\nreturn ''.match(O) === 42;"
      },
      {
        "name": "Symbol.match, RegExp constructor",
        "exec": "var re = /./;\nre[Symbol.match] = false;\nvar foo = {constructor: RegExp};\nfoo[Symbol.match] = true;\nreturn RegExp(re) !== re && RegExp(foo) === foo;"
      },
      {
        "name": "Symbol.match, String.prototype.startsWith",
        "exec": "var re = /./;\ntry {\n  '/./'.startsWith(re);\n} catch(e){\n  re[Symbol.match] = false;\n  return '/./'.startsWith(re);\n}"
      },
      {
        "name": "Symbol.match, String.prototype.endsWith",
        "exec": "var re = /./;\ntry {\n  '/./'.endsWith(re);\n} catch(e){\n  re[Symbol.match] = false;\n  return '/./'.endsWith(re);\n}"
      },
      {
        "name": "Symbol.match, String.prototype.includes",
        "exec": "var re = /./;\ntry {\n  '/./'.includes(re);\n} catch(e){\n  re[Symbol.match] = false;\n  return '/./'.includes(re);\n}"
      },
      {
        "name": "Symbol.toPrimitive",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toPrimitive",
        "exec": "var a = {}, b = {}, c = {};\nvar passed = 0;\na[Symbol.toPrimitive] = function(hint) { passed += hint === \"number\";  return 0; };\nb[Symbol.toPrimitive] = function(hint) { passed += hint === \"string\";  return 0; };\nc[Symbol.toPrimitive] = function(hint) { passed += hint === \"default\"; return 0; };\n\na >= 0;\nb in {};\nc == 0; // eslint-disable-line eqeqeq\nreturn passed === 3;"
      },
      {
        "name": "Symbol.toStringTag",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/toStringTag",
        "exec": "var a = {};\na[Symbol.toStringTag] = \"foo\";\nreturn (a + \"\") === \"[object foo]\";"
      },
      {
        "name": "Symbol.toStringTag affects existing built-ins",
        "exec": "var s = Symbol.toStringTag;\nvar passed = true;\n[\n  [Array.prototype, []],\n  [String.prototype, ''],\n  [arguments, arguments],\n  [Function.prototype, function(){}],\n  [Error.prototype, new Error()],\n  [Boolean.prototype, true],\n  [Number.prototype, 2],\n  [Date.prototype, new Date()],\n  [RegExp.prototype, /./]\n].forEach(function(pair){\n  pair[0][s] = \"foo\";\n  passed &= (Object.prototype.toString.call(pair[1]) === \"[object foo]\");\n  delete pair[0][s];\n});\nreturn passed;"
      },
      {
        "name": "Symbol.toStringTag, new built-ins",
        "exec": "var passed = true;\nvar s = Symbol.toStringTag;\n[\n  [String, \"String Iterator\"],\n  [Array, \"Array Iterator\"],\n  [Map, \"Map Iterator\"],\n  [Set, \"Set Iterator\"]\n].forEach(function(pair){\n  var iterProto = Object.getPrototypeOf(new pair[0]()[Symbol.iterator]());\n  passed = passed\n    && iterProto.hasOwnProperty(s)\n    && iterProto[s] === pair[1];\n});\npassed = passed\n  && Object.getPrototypeOf(function*(){})[s] === \"GeneratorFunction\"\n  && Object.getPrototypeOf(function*(){}())[s] === \"Generator\"\n  && Map.prototype[s] === \"Map\"\n  && Set.prototype[s] === \"Set\"\n  && ArrayBuffer.prototype[s] === \"ArrayBuffer\"\n  && DataView.prototype[s] === \"DataView\"\n  && Promise.prototype[s] === \"Promise\"\n  && Symbol.prototype[s] === \"Symbol\"\n  && typeof Object.getOwnPropertyDescriptor(\n    Object.getPrototypeOf(Int8Array).prototype, Symbol.toStringTag).get === \"function\";\n  return passed;"
      },
      {
        "name": "Symbol.toStringTag, misc. built-ins",
        "exec": "var s = Symbol.toStringTag;\nreturn Math[s] === \"Math\"\n  && JSON[s] === \"JSON\";"
      },
      {
        "name": "Symbol.unscopables",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/unscopables",
        "exec": "var a = { foo: 1, bar: 2 };\na[Symbol.unscopables] = { bar: true };\nwith (a) {\n  return foo === 1 && typeof bar === \"undefined\";\n}"
      }
    ]
  },
  {
    "name": "Object static methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-object-constructor",
    "subtests": [
      {
        "name": "Object.assign",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign",
        "exec": "var o = Object.assign({a:true}, {b:true}, {c:true});\nreturn \"a\" in o && \"b\" in o && \"c\" in o;"
      },
      {
        "name": "Object.is",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is",
        "exec": "return typeof Object.is === 'function' &&\n  Object.is(NaN, NaN) &&\n !Object.is(-0, 0);"
      },
      {
        "name": "Object.getOwnPropertySymbols",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertySymbols",
        "exec": "var o = {};\nvar sym = Symbol(), sym2 = Symbol(), sym3 = Symbol();\no[sym]  = true;\no[sym2] = true;\no[sym3] = true;\nvar result = Object.getOwnPropertySymbols(o);\nreturn result[0] === sym\n  && result[1] === sym2\n  && result[2] === sym3;"
      },
      {
        "name": "Object.setPrototypeOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/setPrototypeOf",
        "exec": "return Object.setPrototypeOf({}, Array.prototype) instanceof Array;"
      }
    ]
  },
  {
    "name": "function \"name\" property",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-setfunctionname",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name",
    "subtests": [
      {
        "name": "function statements",
        "exec": "function foo(){};\nreturn foo.name === 'foo' &&\n  (function(){}).name === '';"
      },
      {
        "name": "function expressions",
        "exec": "return (function foo(){}).name === 'foo' &&\n  (function(){}).name === '';"
      },
      {
        "name": "new Function",
        "exec": "return (new Function).name === \"anonymous\";"
      },
      {
        "name": "bound functions",
        "exec": "function foo() {};\nreturn foo.bind({}).name === \"bound foo\" &&\n  (function(){}).bind({}).name === \"bound \";"
      },
      {
        "name": "variables (function)",
        "exec": "var foo = function() {};\nvar bar = function baz() {};\nreturn foo.name === \"foo\" && bar.name === \"baz\";"
      },
      {
        "name": "object methods (function)",
        "exec": "var o = { foo: function(){}, bar: function baz(){}};\no.qux = function(){};\nreturn o.foo.name === \"foo\" &&\n       o.bar.name === \"baz\" &&\n       o.qux.name === \"\";"
      },
      {
        "name": "accessor properties",
        "exec": "var o = { get foo(){}, set foo(x){} };\nvar descriptor = Object.getOwnPropertyDescriptor(o, \"foo\");\nreturn descriptor.get.name === \"get foo\" &&\n       descriptor.set.name === \"set foo\";"
      },
      {
        "name": "shorthand methods",
        "exec": "var o = { foo(){} };\nreturn o.foo.name === \"foo\";"
      },
      {
        "name": "shorthand methods (no lexical binding)",
        "exec": "var f = \"foo\";\nreturn ({f() { return f; }}).f() === \"foo\";"
      },
      {
        "name": "symbol-keyed methods",
        "exec": "var sym1 = Symbol(\"foo\");\nvar sym2 = Symbol();\nvar o = {\n  [sym1]: function(){},\n  [sym2]: function(){}\n};\n\nreturn o[sym1].name === \"[foo]\" &&\n       o[sym2].name === \"\";"
      },
      {
        "name": "class statements",
        "exec": "class foo {};\nclass bar { static name() {} };\nreturn foo.name === \"foo\" &&\n  typeof bar.name === \"function\";"
      },
      {
        "name": "class expressions",
        "exec": "return class foo {}.name === \"foo\" &&\n  typeof class bar { static name() {} }.name === \"function\";"
      },
      {
        "name": "variables (class)",
        "exec": "var foo = class {};\nvar bar = class baz {};\nvar qux = class { static name() {} };\nreturn foo.name === \"foo\" &&\n       bar.name === \"baz\" &&\n       typeof qux.name === \"function\";"
      },
      {
        "name": "object methods (class)",
        "exec": "var o = { foo: class {}, bar: class baz {}};\no.qux = class {};\nreturn o.foo.name === \"foo\" &&\n       o.bar.name === \"baz\" &&\n       o.qux.name === \"\";"
      },
      {
        "name": "class prototype methods",
        "exec": "class C { foo(){} };\nreturn (new C).foo.name === \"foo\";"
      },
      {
        "name": "class static methods",
        "exec": "class C { static foo(){} };\nreturn C.foo.name === \"foo\";"
      },
      {
        "name": "isn't writable, is configurable",
        "exec": "var descriptor = Object.getOwnPropertyDescriptor(function f(){},\"name\");\nreturn descriptor.enumerable   === false &&\n       descriptor.writable     === false &&\n       descriptor.configurable === true;"
      }
    ]
  },
  {
    "name": "String static methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-string-constructor",
    "subtests": [
      {
        "name": "String.raw",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/raw",
        "exec": "return typeof String.raw === 'function';"
      },
      {
        "name": "String.fromCodePoint",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint",
        "exec": "return typeof String.fromCodePoint === 'function';"
      }
    ]
  },
  {
    "name": "String.prototype methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-string-prototype-object",
    "subtests": [
      {
        "name": "String.prototype.codePointAt",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/codePointAt",
        "exec": "return typeof String.prototype.codePointAt === 'function';"
      },
      {
        "name": "String.prototype.normalize",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize",
        "exec": "return typeof String.prototype.normalize === \"function\"\n  && \"c\\u0327\\u0301\".normalize(\"NFC\") === \"\\u1e09\"\n  && \"\\u1e09\".normalize(\"NFD\") === \"c\\u0327\\u0301\";"
      },
      {
        "name": "String.prototype.repeat",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat",
        "exec": "return typeof String.prototype.repeat === 'function'\n  && \"foo\".repeat(3) === \"foofoofoo\";"
      },
      {
        "name": "String.prototype.startsWith",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith",
        "exec": "return typeof String.prototype.startsWith === 'function'\n  && \"foobar\".startsWith(\"foo\");"
      },
      {
        "name": "String.prototype.startsWith throws on RegExp",
        "exec": "try {\n  \"a\".startsWith(/./);\n} catch(e) {\n  return typeof String.prototype.startsWith === 'function';\n}"
      },
      {
        "name": "String.prototype.endsWith",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith",
        "exec": "return typeof String.prototype.endsWith === 'function'\n  && \"foobar\".endsWith(\"bar\");"
      },
      {
        "name": "String.prototype.endsWith throws on RegExp",
        "exec": "try {\n  \"a\".endsWith(/./);\n} catch(e) {\n  return typeof String.prototype.endsWith === 'function';\n}"
      },
      {
        "name": "String.prototype.includes",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes",
        "exec": "return typeof String.prototype.includes === 'function'\n  && \"foobar\".includes(\"oba\");"
      },
      {
        "name": "String.prototype[Symbol.iterator]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/@@iterator",
        "exec": "return typeof String.prototype[Symbol.iterator] === 'function';"
      },
      {
        "name": "String iterator prototype chain",
        "exec": "// Iterator instance\nvar iterator = ''[Symbol.iterator]();\n// %StringIteratorPrototype%\nvar proto1 = Object.getPrototypeOf(iterator);\n// %IteratorPrototype%\nvar proto2 = Object.getPrototypeOf(proto1);\n\nreturn proto2.hasOwnProperty(Symbol.iterator) &&\n  !proto1    .hasOwnProperty(Symbol.iterator) &&\n  !iterator  .hasOwnProperty(Symbol.iterator) &&\n  iterator[Symbol.iterator]() === iterator;"
      }
    ]
  },
  {
    "name": "RegExp.prototype properties",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-regexp.prototype",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/prototype",
    "subtests": [
      {
        "name": "RegExp.prototype.flags",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/flags",
        "exec": "return /./igm.flags === \"gim\" && /./.flags === \"\";"
      },
      {
        "name": "RegExp.prototype[Symbol.match]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/@@match",
        "exec": "return typeof RegExp.prototype[Symbol.match] === 'function';"
      },
      {
        "name": "RegExp.prototype[Symbol.replace]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/@@replace",
        "exec": "return typeof RegExp.prototype[Symbol.replace] === 'function';"
      },
      {
        "name": "RegExp.prototype[Symbol.split]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/@@split",
        "exec": "return typeof RegExp.prototype[Symbol.split] === 'function';"
      },
      {
        "name": "RegExp.prototype[Symbol.search]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/@@search",
        "exec": "return typeof RegExp.prototype[Symbol.search] === 'function';"
      },
      {
        "name": "RegExp[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/@@species",
        "exec": "var prop = Object.getOwnPropertyDescriptor(RegExp, Symbol.species);\nreturn 'get' in prop && RegExp[Symbol.species] === RegExp;"
      }
    ]
  },
  {
    "name": "Array static methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-array-constructor",
    "subtests": [
      {
        "name": "Array.from, array-like objects",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from#Array_from_an_Array-like_object_(arguments)",
        "exec": "return Array.from({ 0: \"foo\", 1: \"bar\", length: 2 }) + '' === \"foo,bar\";"
      },
      {
        "name": "Array.from, generator instances",
        "exec": "var iterable = (function*(){ yield 1; yield 2; yield 3; }());\nreturn Array.from(iterable) + '' === \"1,2,3\";"
      },
      {
        "name": "Array.from, generic iterables",
        "exec": "var iterable = global.__createIterableObject([1, 2, 3]);\nreturn Array.from(iterable) + '' === \"1,2,3\";"
      },
      {
        "name": "Array.from, instances of generic iterables",
        "exec": "var iterable = global.__createIterableObject([1, 2, 3]);\nreturn Array.from(Object.create(iterable)) + '' === \"1,2,3\";"
      },
      {
        "name": "Array.from map function, array-like objects",
        "exec": "return Array.from({ 0: \"foo\", 1: \"bar\", length: 2 }, function(e, i) {\n  return e + this.baz + i;\n}, { baz: \"d\" }) + '' === \"food0,bard1\";"
      },
      {
        "name": "Array.from map function, generator instances",
        "exec": "var iterable = (function*(){ yield \"foo\"; yield \"bar\"; yield \"bal\"; }());\nreturn Array.from(iterable, function(e, i) {\n  return e + this.baz + i;\n}, { baz: \"d\" }) + '' === \"food0,bard1,bald2\";"
      },
      {
        "name": "Array.from map function, generic iterables",
        "exec": "var iterable = global.__createIterableObject([\"foo\", \"bar\", \"bal\"]);\nreturn Array.from(iterable, function(e, i) {\n  return e + this.baz + i;\n}, { baz: \"d\" }) + '' === \"food0,bard1,bald2\";"
      },
      {
        "name": "Array.from map function, instances of iterables",
        "exec": "var iterable = global.__createIterableObject([\"foo\", \"bar\", \"bal\"]);\nreturn Array.from(Object.create(iterable), function(e, i) {\n  return e + this.baz + i;\n}, { baz: \"d\" }) + '' === \"food0,bard1,bald2\";"
      },
      {
        "name": "Array.from, iterator closing",
        "exec": "var closed = false;\nvar iter = global.__createIterableObject([1, 2, 3], {\n  'return': function(){ closed = true; return {}; }\n});\ntry {\n  Array.from(iter, function() { throw 42 });\n} catch(e){}\nreturn closed;"
      },
      {
        "name": "Array.of",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of",
        "exec": "return typeof Array.of === 'function' &&\n  Array.of(2)[0] === 2;"
      },
      {
        "name": "Array[Symbol.species]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@species",
        "exec": "var prop = Object.getOwnPropertyDescriptor(Array, Symbol.species);\nreturn 'get' in prop && Array[Symbol.species] === Array;"
      }
    ]
  },
  {
    "name": "Array.prototype methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "medium",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-array-prototype-object",
    "subtests": [
      {
        "name": "Array.prototype.copyWithin",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/copyWithin",
        "exec": "return typeof Array.prototype.copyWithin === 'function';"
      },
      {
        "name": "Array.prototype.find",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find",
        "exec": "return typeof Array.prototype.find === 'function';"
      },
      {
        "name": "Array.prototype.findIndex",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex",
        "exec": "return typeof Array.prototype.findIndex === 'function';"
      },
      {
        "name": "Array.prototype.fill",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill",
        "exec": "return typeof Array.prototype.fill === 'function';"
      },
      {
        "name": "Array.prototype.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/keys",
        "exec": "return typeof Array.prototype.keys === 'function';"
      },
      {
        "name": "Array.prototype.values",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/values",
        "exec": "return typeof Array.prototype.values === 'function';"
      },
      {
        "name": "Array.prototype.entries",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/entries",
        "exec": "return typeof Array.prototype.entries === 'function';"
      },
      {
        "name": "Array.prototype.splice",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice",
        "exec": "if ([0, 1, 2].splice(0).length !== 3) {\n  // IE <= 8 and other pre-ES6 engines fail this check\n  return false;\n}\n\nvar a = [1, 2];\nvar result = a.splice();\nif (a.length !== 2 || result.length !== 0) {\n  // Safari 5.0 has this bug\n  return false;\n}\n\nvar obj = {};\nArray.prototype.splice.call(obj, 0, 0, 1);\nif (obj.length !== 1) {\n  return false;\n}\n\nvar spliceWorksWithLargeSparseArrays = (function () {\n  // Per https://github.com/es-shims/es5-shim/issues/295\n  // Safari 7/8 breaks with sparse arrays of size 1e5 or greater\n  var arr = new Array(1e5);\n  // note: the index MUST be 8 or larger or the test will false pass\n  arr[8] = 'x';\n  arr.splice(1, 1);\n  for (var i = 0; i < arr.length; i += 1) {\n    if (arr[i] === 'x') {\n      return i === 7;\n    }\n  }\n  return false;\n}());\nvar spliceWorksWithSmallSparseArrays = (function () {\n  // Per https://github.com/es-shims/es5-shim/issues/295\n  // Opera 12.15 breaks on this, no idea why.\n  var n = 256;\n  var arr = [];\n  arr[n] = 'a';\n  arr.splice(n + 1, 0, 'b');\n  return arr[n] === 'a';\n}());\n\nreturn spliceWorksWithLargeSparseArrays && spliceWorksWithSmallSparseArrays;"
      },
      {
        "name": "Array.prototype[Symbol.iterator]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@iterator",
        "exec": "return typeof Array.prototype[Symbol.iterator] === 'function';"
      },
      {
        "name": "Array iterator prototype chain",
        "exec": "// Iterator instance\nvar iterator = [][Symbol.iterator]();\n// %ArrayIteratorPrototype%\nvar proto1 = Object.getPrototypeOf(iterator);\n// %IteratorPrototype%\nvar proto2 = Object.getPrototypeOf(proto1);\n\nreturn proto2.hasOwnProperty(Symbol.iterator) &&\n  !proto1    .hasOwnProperty(Symbol.iterator) &&\n  !iterator  .hasOwnProperty(Symbol.iterator) &&\n  iterator[Symbol.iterator]() === iterator;"
      },
      {
        "name": "Array.prototype[Symbol.unscopables]",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@unscopables",
        "exec": "var unscopables = Array.prototype[Symbol.unscopables];\nif (!unscopables) {\n  return false;\n}\nvar ns = \"find,findIndex,fill,copyWithin,entries,keys,values\".split(\",\");\nfor (var i = 0; i < ns.length; i++) {\n  if (Array.prototype[ns[i]] && !unscopables[ns[i]]) return false;\n}\nreturn true;"
      }
    ]
  },
  {
    "name": "Number properties",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-isfinite-number",
    "subtests": [
      {
        "name": "Number.isFinite",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isFinite",
        "exec": "return typeof Number.isFinite === 'function';"
      },
      {
        "name": "Number.isInteger",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger",
        "exec": "return typeof Number.isInteger === 'function';"
      },
      {
        "name": "Number.isSafeInteger",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger",
        "exec": "return typeof Number.isSafeInteger === 'function';"
      },
      {
        "name": "Number.isNaN",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN",
        "exec": "return typeof Number.isNaN === 'function';"
      },
      {
        "name": "Number.parseFloat",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseFloat",
        "exec": "var actualGlobal = Function('return this')();\nreturn typeof Number.parseFloat === 'function'\n  && Number.parseFloat === actualGlobal.parseFloat;"
      },
      {
        "name": "Number.parseInt",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseInt",
        "exec": "var actualGlobal = Function('return this')();\nreturn typeof Number.parseInt === 'function'\n  && Number.parseInt === actualGlobal.parseInt;"
      },
      {
        "name": "Number.EPSILON",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/EPSILON",
        "exec": "return typeof Number.EPSILON === 'number';"
      },
      {
        "name": "Number.MIN_SAFE_INTEGER",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MIN_SAFE_INTEGER",
        "exec": "return typeof Number.MIN_SAFE_INTEGER === 'number';"
      },
      {
        "name": "Number.MAX_SAFE_INTEGER",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER",
        "exec": "return typeof Number.MAX_SAFE_INTEGER === 'number';"
      }
    ]
  },
  {
    "name": "Math methods",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-math",
    "subtests": [
      {
        "name": "Math.clz32",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/clz32",
        "exec": "return typeof Math.clz32 === \"function\";"
      },
      {
        "name": "Math.imul",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul",
        "exec": "return typeof Math.imul === \"function\";"
      },
      {
        "name": "Math.sign",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign",
        "exec": "return typeof Math.sign === \"function\";"
      },
      {
        "name": "Math.log10",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log10",
        "exec": "return typeof Math.log10 === \"function\";"
      },
      {
        "name": "Math.log2",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log2",
        "exec": "return typeof Math.log2 === \"function\";"
      },
      {
        "name": "Math.log1p",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/log1p",
        "exec": "return typeof Math.log1p === \"function\";"
      },
      {
        "name": "Math.expm1",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/expm1",
        "exec": "return typeof Math.expm1 === \"function\";"
      },
      {
        "name": "Math.cosh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/cosh",
        "exec": "return typeof Math.cosh === \"function\";"
      },
      {
        "name": "Math.sinh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sinh",
        "exec": "return typeof Math.sinh === \"function\";"
      },
      {
        "name": "Math.tanh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/tanh",
        "exec": "return typeof Math.tanh === \"function\";"
      },
      {
        "name": "Math.acosh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/acosh",
        "exec": "return typeof Math.acosh === \"function\";"
      },
      {
        "name": "Math.asinh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/asinh",
        "exec": "return typeof Math.asinh === \"function\";"
      },
      {
        "name": "Math.atanh",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/atanh",
        "exec": "return typeof Math.atanh === \"function\";"
      },
      {
        "name": "Math.trunc",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/trunc",
        "exec": "return typeof Math.trunc === \"function\";"
      },
      {
        "name": "Math.fround",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/fround",
        "exec": "return typeof Math.fround === \"function\";"
      },
      {
        "name": "Math.cbrt",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/cbrt",
        "exec": "return typeof Math.cbrt === \"function\";"
      },
      {
        "name": "Math.hypot",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/hypot",
        "exec": "return Math.hypot() === 0 &&\n  Math.hypot(1) === 1 &&\n  Math.hypot(9, 12, 20) === 25 &&\n  Math.hypot(27, 36, 60, 100) === 125;"
      }
    ]
  },
  {
    "name": "Date.prototype[Symbol.toPrimitive]",
    "target": "es6",
    "category": "built-in extensions",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-date.prototype-@@toprimitive",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/@@toPrimitive",
    "exec": "var tp = Date.prototype[Symbol.toPrimitive];\nreturn tp.call(Object(2), \"number\") === 2\n  && tp.call(Object(2), \"string\") === \"2\"\n  && tp.call(Object(2), \"default\") === \"2\";"
  },
  {
    "name": "Array is subclassable",
    "target": "es6",
    "category": "subclassing",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-array-constructor",
    "subtests": [
      {
        "name": "length property (accessing)",
        "exec": "class C extends Array {}\nvar c = new C();\nvar len1 = c.length;\nc[2] = 'foo';\nvar len2 = c.length;\nreturn len1 === 0 && len2 === 3;"
      },
      {
        "name": "length property (setting)",
        "exec": "class C extends Array {}\nvar c = new C();\nc[2] = 'foo';\nc.length = 1;\nreturn c.length === 1 && !(2 in c);"
      },
      {
        "name": "correct prototype chain",
        "exec": "class C extends Array {}\nvar c = new C();\nreturn c instanceof C && c instanceof Array && Object.getPrototypeOf(C) === Array;"
      },
      {
        "name": "Array.isArray support",
        "exec": "class C extends Array {}\nreturn Array.isArray(new C());"
      },
      {
        "name": "Array.prototype.concat",
        "exec": "class C extends Array {}\nvar c = new C();\nreturn c.concat(1) instanceof C;"
      },
      {
        "name": "Array.prototype.filter",
        "exec": "class C extends Array {}\nvar c = new C();\nreturn c.filter(Boolean) instanceof C;"
      },
      {
        "name": "Array.prototype.map",
        "exec": "class C extends Array {}\nvar c = new C();\nreturn c.map(Boolean) instanceof C;"
      },
      {
        "name": "Array.prototype.slice",
        "exec": "class C extends Array {}\nvar c = new C();\nc.push(2,4,6);\nreturn c.slice(1,2) instanceof C;"
      },
      {
        "name": "Array.prototype.splice",
        "exec": "class C extends Array {}\nvar c = new C();\nc.push(2,4,6);\nreturn c.splice(1,2) instanceof C;"
      },
      {
        "name": "Array.from",
        "exec": "class C extends Array {}\nreturn C.from({ length: 0 }) instanceof C;"
      },
      {
        "name": "Array.of",
        "exec": "class C extends Array {}\nreturn C.of(0) instanceof C;"
      }
    ]
  },
  {
    "name": "RegExp is subclassable",
    "target": "es6",
    "category": "subclassing",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-regexp-constructor",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "class R extends RegExp {}\nvar r = new R(\"baz\",\"g\");\nreturn r.global && r.source === \"baz\";"
      },
      {
        "name": "correct prototype chain",
        "exec": "class R extends RegExp {}\nvar r = new R(\"baz\",\"g\");\nreturn r instanceof R && r instanceof RegExp && Object.getPrototypeOf(R) === RegExp;"
      },
      {
        "name": "RegExp.prototype.exec",
        "exec": "class R extends RegExp {}\nvar r = new R(\"baz\",\"g\");\nreturn r.exec(\"foobarbaz\")[0] === \"baz\" && r.lastIndex === 9;"
      },
      {
        "name": "RegExp.prototype.test",
        "exec": "class R extends RegExp {}\nvar r = new R(\"baz\");\nreturn r.test(\"foobarbaz\");"
      }
    ]
  },
  {
    "name": "Function is subclassable",
    "target": "es6",
    "category": "subclassing",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-function-constructor",
    "subtests": [
      {
        "name": "can be called",
        "exec": "class C extends Function {}\nvar c = new C(\"return 'foo';\");\nreturn c() === 'foo';"
      },
      {
        "name": "correct prototype chain",
        "exec": "class C extends Function {}\nvar c = new C(\"return 'foo';\");\nreturn c instanceof C && c instanceof Function && Object.getPrototypeOf(C) === Function;"
      },
      {
        "name": "can be used with \"new\"",
        "exec": "class C extends Function {}\nvar c = new C(\"this.bar = 2;\");\nc.prototype.baz = 3;\nreturn new c().bar === 2 && new c().baz === 3;"
      },
      {
        "name": "Function.prototype.call",
        "exec": "class C extends Function {}\nvar c = new C(\"x\", \"return this.bar + x;\");\nreturn c.call({bar:1}, 2) === 3;"
      },
      {
        "name": "Function.prototype.apply",
        "exec": "class C extends Function {}\nvar c = new C(\"x\", \"return this.bar + x;\");\nreturn c.apply({bar:1}, [2]) === 3;"
      },
      {
        "name": "Function.prototype.bind",
        "exec": "class C extends Function {}\nvar c = new C(\"x\", \"y\", \"return this.bar + x + y;\").bind({bar:1}, 2);\nreturn c(6) === 9 && c instanceof C;"
      }
    ]
  },
  {
    "name": "Promise is subclassable",
    "target": "es6",
    "category": "subclassing",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-function-constructor",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "class P extends Promise {}\nvar p1 = new P(function(resolve, reject) { resolve(\"foo\"); });\nvar p2 = new P(function(resolve, reject) { reject(\"quux\"); });\nvar score = +(p1 instanceof P);\n\nfunction thenFn(result)  { score += (result === \"foo\");  check(); }\nfunction catchFn(result) { score += (result === \"quux\"); check(); }\nfunction shouldNotRun(result)  { score = -Infinity;   }\n\np1.then(thenFn, shouldNotRun);\np2.then(shouldNotRun, catchFn);\np1.catch(shouldNotRun);\np2.catch(catchFn);\n\np1.then(function() {\n  // P.prototype.then() should return a new P\n  score += p1.then() instanceof P && p1.then() !== p1;\n  check();\n});\n\nfunction check() {\n  if (score === 5) asyncTestPassed();\n}"
      },
      {
        "name": "correct prototype chain",
        "exec": "class C extends Promise {}\nvar c = new C(function(resolve, reject) { resolve(\"foo\"); });\nreturn c instanceof C && c instanceof Promise && Object.getPrototypeOf(C) === Promise;"
      },
      {
        "name": "Promise.all",
        "exec": "class P extends Promise {}\nvar fulfills = P.all([\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"foo\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"bar\"); })\n]);\nvar rejects = P.all([\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"baz\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"qux\"); })\n]);\nvar score = +(fulfills instanceof P);\nfulfills.then(function(result) { score += (result + \"\" === \"foo,bar\"); check(); });\nrejects.catch(function(result) { score += (result === \"qux\"); check(); });\n\nfunction check() {\n  if (score === 3) asyncTestPassed();\n}"
      },
      {
        "name": "Promise.race",
        "exec": "class P extends Promise {}\nvar fulfills = P.race([\n  new Promise(function(resolve)   { setTimeout(resolve,1000,\"foo\"); }),\n  new Promise(function(_, reject) { setTimeout(reject, 2000,\"bar\"); })\n]);\nvar rejects = P.race([\n  new Promise(function(_, reject) { setTimeout(reject, 1000,\"baz\"); }),\n  new Promise(function(resolve)   { setTimeout(resolve,2000,\"qux\"); })\n]);\nvar score = +(fulfills instanceof P);\nfulfills.then(function(result) { score += (result === \"foo\"); check(); });\nrejects.catch(function(result) { score += (result === \"baz\"); check(); });\n\nfunction check() {\n  if (score === 3) asyncTestPassed();\n}"
      }
    ]
  },
  {
    "name": "miscellaneous subclassables",
    "target": "es6",
    "category": "subclassing",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-boolean-constructor",
    "subtests": [
      {
        "name": "Boolean is subclassable",
        "exec": "class C extends Boolean {}\nvar c = new C(true);\nreturn c instanceof Boolean\n  && c instanceof C\n  && c == true; // eslint-disable-line eqeqeq"
      },
      {
        "name": "Number is subclassable",
        "exec": "class C extends Number {}\nvar c = new C(6);\nreturn c instanceof Number\n  && c instanceof C\n  && +c === 6;"
      },
      {
        "name": "String is subclassable",
        "exec": "class C extends String {}\nvar c = new C(\"golly\");\nreturn c instanceof String\n  && c instanceof C\n  && c + '' === \"golly\"\n  && c[0] === \"g\"\n  && c.length === 5;"
      },
      {
        "name": "Error is subclassable",
        "exec": "class C extends Error {}\nvar c = new C();\nreturn c instanceof Error\n  && c instanceof C\n  && Object.prototype.toString.call(c) === \"[object Error]\";"
      },
      {
        "name": "Map is subclassable",
        "exec": "var key = {};\nclass M extends Map {}\nvar map = new M();\n\nmap.set(key, 123);\n\nreturn map instanceof M && map.has(key) && map.get(key) === 123;"
      },
      {
        "name": "Set is subclassable",
        "exec": "var obj = {};\nclass S extends Set {}\nvar set = new S();\n\nset.add(123);\nset.add(123);\n\nreturn set instanceof S && set.has(123);"
      }
    ]
  },
  {
    "name": "prototype of bound functions",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-boundfunctioncreate",
    "subtests": [
      {
        "name": "basic functions",
        "exec": "function correctProtoBound(proto) {\n  var f = function(){};\n  if (Object.setPrototypeOf) {\n    Object.setPrototypeOf(f, proto);\n  } else {\n    f.__proto__ = proto;\n  }\n  var boundF = Function.prototype.bind.call(f, null);\n  return Object.getPrototypeOf(boundF) === proto;\n}\nreturn correctProtoBound(Function.prototype)\n  && correctProtoBound({})\n  && correctProtoBound(null);"
      },
      {
        "name": "generator functions",
        "exec": "function correctProtoBound(proto) {\n  var f = function*(){};\n  if (Object.setPrototypeOf) {\n    Object.setPrototypeOf(f, proto);\n  } else {\n    f.__proto__ = proto;\n  }\n  var boundF = Function.prototype.bind.call(f, null);\n  return Object.getPrototypeOf(boundF) === proto;\n}\nreturn correctProtoBound(Function.prototype)\n  && correctProtoBound({})\n  && correctProtoBound(null);"
      },
      {
        "name": "arrow functions",
        "exec": "function correctProtoBound(proto) {\n  var f = ()=>5;\n  if (Object.setPrototypeOf) {\n    Object.setPrototypeOf(f, proto);\n  } else {\n    f.__proto__ = proto;\n  }\n  var boundF = Function.prototype.bind.call(f, null);\n  return Object.getPrototypeOf(boundF) === proto;\n}\nreturn correctProtoBound(Function.prototype)\n  && correctProtoBound({})\n  && correctProtoBound(null);"
      },
      {
        "name": "classes",
        "exec": "function correctProtoBound(proto) {\n  class C {}\n  if (Object.setPrototypeOf) {\n    Object.setPrototypeOf(C, proto);\n  } else {\n    C.__proto__ = proto;\n  }\n  var boundF = Function.prototype.bind.call(C, null);\n  return Object.getPrototypeOf(boundF) === proto;\n}\nreturn correctProtoBound(Function.prototype)\n  && correctProtoBound({})\n  && correctProtoBound(null);"
      },
      {
        "name": "subclasses",
        "exec": "function correctProtoBound(superclass) {\n  class C extends superclass {\n    constructor() {\n      return Object.create(null);\n    }\n  }\n  var boundF = Function.prototype.bind.call(C, null);\n  return Object.getPrototypeOf(boundF) === Object.getPrototypeOf(C);\n}\nreturn correctProtoBound(function(){})\n  && correctProtoBound(Array)\n  && correctProtoBound(null);"
      }
    ]
  },
  {
    "name": "Proxy, internal 'get' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/get",
    "subtests": [
      {
        "name": "ToPrimitive",
        "exec": "// ToPrimitive -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({toString:Function()}, { get: function(o, k) { get.push(k); return o[k]; }});\np + 3;\nreturn get[0] === Symbol.toPrimitive && get.slice(1) + '' === \"valueOf,toString\";"
      },
      {
        "name": "CreateListFromArrayLike",
        "exec": "// CreateListFromArrayLike -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({length:2, 0:0, 1:0}, { get: function(o, k) { get.push(k); return o[k]; }});\nFunction.prototype.apply({}, p);\nreturn get + '' === \"length,0,1\";"
      },
      {
        "name": "instanceof operator",
        "exec": "// InstanceofOperator -> GetMethod -> GetV -> [[Get]]\n// InstanceofOperator -> OrdinaryHasInstance -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }});\n({}) instanceof p;\nreturn get[0] === Symbol.hasInstance && get.slice(1) + '' === \"prototype\";"
      },
      {
        "name": "HasBinding",
        "exec": "// HasBinding -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({foo:1}, { get: function(o, k) { get.push(k); return o[k]; }});\np[Symbol.unscopables] = p;\nwith(p) {\n  typeof foo;\n}\nreturn get[0] === Symbol.unscopables && get.slice(1) + '' === \"foo\";"
      },
      {
        "name": "CreateDynamicFunction",
        "exec": "// CreateDynamicFunction -> GetPrototypeFromConstructor -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy(Function, { get: function(o, k) { get.push(k); return o[k]; }});\nnew p;\nreturn get + '' === \"prototype\";"
      },
      {
        "name": "ClassDefinitionEvaluation",
        "exec": "// ClassDefinitionEvaluation -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }});\nclass C extends p {}\nreturn get + '' === \"prototype\";"
      },
      {
        "name": "IteratorComplete, IteratorValue",
        "exec": "// IteratorComplete -> Get -> [[Get]]\n// IteratorValue -> Get -> [[Get]]\nvar get = [];\nvar iterable = {};\niterable[Symbol.iterator] = function() {\n  return {\n    next: function() {\n      return new Proxy({ value: 2, done: false }, { get: function(o, k) { get.push(k); return o[k]; }});\n    }\n  };\n}\nvar i = 0;\nfor(var e of iterable) {\n  if (++i >= 2) break;\n}\nreturn get + '' === \"done,value,done,value\";"
      },
      {
        "name": "ToPropertyDescriptor",
        "exec": "// ToPropertyDescriptor -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({\n    enumerable: true, configurable: true, value: true,\n    writable: true, get: Function(), set: Function()\n  }, { get: function(o, k) { get.push(k); return o[k]; }});\ntry {\n  // This will throw, since it will have true for both \"get\" and \"value\",\n  // but not before performing a Get on every property.\n  Object.defineProperty({}, \"foo\", p);\n} catch(e) {\n  return get + '' === \"enumerable,configurable,value,writable,get,set\";\n}"
      },
      {
        "name": "Object.assign",
        "exec": "// Object.assign -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({foo:1, bar:2}, { get: function(o, k) { get.push(k); return o[k]; }});\nObject.assign({}, p);\nreturn get + '' === \"foo,bar\";"
      },
      {
        "name": "Object.defineProperties",
        "exec": "// Object.defineProperties -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({foo:{}, bar:{}}, { get: function(o, k) { get.push(k); return o[k]; }});\nObject.defineProperties({}, p);\nreturn get + '' === \"foo,bar\";"
      },
      {
        "name": "Function.prototype.bind",
        "exec": "// Function.prototype.bind -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy(Function(), { get: function(o, k) { get.push(k); return o[k]; }});\nFunction.prototype.bind.call(p);\nreturn get + '' === \"length,name\";"
      },
      {
        "name": "Error.prototype.toString",
        "exec": "// Error.prototype.toString -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }});\nError.prototype.toString.call(p);\nreturn get + '' === \"name,message\";"
      },
      {
        "name": "String.raw",
        "exec": "// String.raw -> Get -> [[Get]]\nvar get = [];\nvar raw = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }});\nvar p = new Proxy({raw: raw}, { get: function(o, k) { get.push(k); return o[k]; }});\nString.raw(p);\nreturn get + '' === \"raw,length,0,1\";"
      },
      {
        "name": "RegExp constructor",
        "exec": "// RegExp -> Get -> [[Get]]\nvar get = [];\nvar re = { constructor: null };\nre[Symbol.match] = true;\nvar p = new Proxy(re, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp(p);\nreturn get[0] === Symbol.match && get.slice(1) + '' === \"constructor,source,flags\";"
      },
      {
        "name": "RegExp.prototype.flags",
        "exec": "// RegExp.prototype.flags -> Get -> [[Get]]\nvar expected = [];\n// Sorted alphabetically by shortname – \"gimsuy\".\nif ('hasIndices' in RegExp.prototype) expected.push('hasIndices');\nif ('global' in RegExp.prototype) expected.push('global');\nif ('ignoreCase' in RegExp.prototype) expected.push('ignoreCase');\nif ('multiline' in RegExp.prototype) expected.push('multiline');\nif ('dotAll' in RegExp.prototype) expected.push('dotAll');\nif ('unicode' in RegExp.prototype) expected.push('unicode');\nif ('unicodeSets' in RegExp.prototype) expected.push('unicodeSets');\nif ('sticky' in RegExp.prototype) expected.push('sticky');\n\nvar actual = [];\nvar p = new Proxy({}, { get: function(o, k) { actual.push(k); return o[k]; }});\nObject.getOwnPropertyDescriptor(RegExp.prototype, 'flags').get.call(p);\nif (expected.length !== actual.length) return false;\nfor (var i = 0; i < expected.length; i++) {\n  if (expected[i] !== actual[i]) return false;\n}\nreturn true;"
      },
      {
        "name": "RegExp.prototype.test",
        "exec": "// RegExp.prototype.test -> RegExpExec -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype.test.call(p);\nreturn get + '' === \"exec\";"
      },
      {
        "name": "RegExp.prototype.toString",
        "exec": "// RegExp.prototype.toString -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype.toString.call(p);\nreturn get + '' === \"source,flags\";"
      },
      {
        "name": "RegExp.prototype[Symbol.match]",
        "exec": "// RegExp.prototype[Symbol.match] -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype[Symbol.match].call(p);\np.global = true;\nRegExp.prototype[Symbol.match].call(p);\nvar str = get + '';\nreturn str === \"global,exec,global,unicode,exec\" || str === 'flags,exec,flags,exec';"
      },
      {
        "name": "RegExp.prototype[Symbol.replace]",
        "exec": "// RegExp.prototype[Symbol.replace] -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype[Symbol.replace].call(p);\np.global = true;\nRegExp.prototype[Symbol.replace].call(p);\nvar str = get + '';\nreturn str === \"global,exec,global,unicode,exec\" || str === 'flags,exec,flags,exec';"
      },
      {
        "name": "RegExp.prototype[Symbol.search]",
        "exec": "// RegExp.prototype[Symbol.search] -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({ exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype[Symbol.search].call(p);\nreturn get + '' === \"lastIndex,exec,lastIndex\";"
      },
      {
        "name": "RegExp.prototype[Symbol.split]",
        "exec": "// RegExp.prototype[Symbol.split] -> Get -> [[Get]]\nvar get = [];\nvar constructor = Function();\nconstructor[Symbol.species] = Object;\nvar p = new Proxy({ constructor: constructor, flags: '', exec: function() { return null; } }, { get: function(o, k) { get.push(k); return o[k]; }});\nRegExp.prototype[Symbol.split].call(p, \"\");\nreturn get + '' === \"constructor,flags,exec\";"
      },
      {
        "name": "Array.from",
        "exec": "// Array.from -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }});\nArray.from(p);\nreturn get[0] === Symbol.iterator && get.slice(1) + '' === \"length,0,1\";"
      },
      {
        "name": "Array.prototype.concat",
        "exec": "// Array.prototype.concat -> Get -> [[Get]]\nvar get = [];\nvar arr = [1];\narr.constructor = void undefined;\nvar p = new Proxy(arr, { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.concat.call(p,p);\nreturn get[0] === \"constructor\"\n  && get[1] === Symbol.isConcatSpreadable\n  && get[2] === \"length\"\n  && get[3] === \"0\"\n  && get[4] === get[1] && get[5] === get[2] && get[6] === get[3]\n  && get.length === 7;"
      },
      {
        "name": "Array.prototype iteration methods",
        "exec": "// Array.prototype methods -> Get -> [[Get]]\nvar methods = ['copyWithin', 'every', 'fill', 'filter', 'find', 'findIndex', 'forEach',\n  'indexOf', 'join', 'lastIndexOf', 'map', 'reduce', 'reduceRight', 'some'];\nvar get;\nvar p = new Proxy({length: 2, 0: '', 1: ''}, { get: function(o, k) { get.push(k); return o[k]; }});\nfor(var i = 0; i < methods.length; i+=1) {\n  get = [];\n  Array.prototype[methods[i]].call(p, Function());\n  if (get + '' !== (\n    methods[i] === 'fill' ? \"length\" :\n    methods[i] === 'every' ? \"length,0\" :\n    methods[i] === 'lastIndexOf' || methods[i] === 'reduceRight' ? \"length,1,0\" :\n    \"length,0,1\"\n  )) {\n    return false;\n  }\n}\nreturn true;"
      },
      {
        "name": "Array.prototype.pop",
        "exec": "// Array.prototype.pop -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.pop.call(p);\nreturn get + '' === \"length,3\";"
      },
      {
        "name": "Array.prototype.reverse",
        "exec": "// Array.prototype.reverse -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy([0,,2,,4,,], { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.reverse.call(p);\nreturn get + '' === \"length,0,4,2\";"
      },
      {
        "name": "Array.prototype.shift",
        "exec": "// Array.prototype.shift -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.shift.call(p);\nreturn get + '' === \"length,0,1,2,3\";"
      },
      {
        "name": "Array.prototype.splice",
        "exec": "// Array.prototype.splice -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy([0,1,2,3], { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.splice.call(p,1,1);\nArray.prototype.splice.call(p,1,0,1);\nreturn get + '' === \"length,constructor,1,2,3,length,constructor,2,1\";"
      },
      {
        "name": "Array.prototype.toString",
        "exec": "// Array.prototype.toString -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({ join:Function() }, { get: function(o, k) { get.push(k); return o[k]; }});\nArray.prototype.toString.call(p);\nreturn get + '' === \"join\";"
      },
      {
        "name": "JSON.stringify",
        "exec": "// JSON.stringify -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }});\nJSON.stringify(p);\nreturn get + '' === \"toJSON\";"
      },
      {
        "name": "Promise resolve functions",
        "exec": "// Promise resolve functions -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({}, { get: function(o, k) { get.push(k); return o[k]; }});\nnew Promise(function(resolve){ resolve(p); });\nreturn get + '' === \"then\";"
      },
      {
        "name": "String.prototype.match",
        "exec": "// String.prototype.match -> Get -> [[Get]]\nvar get = [];\nvar proxied = {};\nproxied[Symbol.toPrimitive] = Function();\nvar p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }});\n\"\".match(p);\nreturn get[0] === Symbol.match && get[1] === Symbol.toPrimitive && get.length === 2;"
      },
      {
        "name": "String.prototype.replace",
        "exec": "// String.prototype.replace functions -> Get -> [[Get]]\nvar get = [];\nvar proxied = {};\nproxied[Symbol.toPrimitive] = Function();\nvar p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }});\n\"\".replace(p);\nreturn get[0] === Symbol.replace && get[1] === Symbol.toPrimitive && get.length === 2;"
      },
      {
        "name": "String.prototype.search",
        "exec": "// String.prototype.search functions -> Get -> [[Get]]\nvar get = [];\nvar proxied = {};\nproxied[Symbol.toPrimitive] = Function();\nvar p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }});\n\"\".search(p);\nreturn get[0] === Symbol.search && get[1] === Symbol.toPrimitive && get.length === 2;"
      },
      {
        "name": "String.prototype.split",
        "exec": "// String.prototype.split functions -> Get -> [[Get]]\nvar get = [];\nvar proxied = {};\nproxied[Symbol.toPrimitive] = Function();\nvar p = new Proxy(proxied, { get: function(o, k) { get.push(k); return o[k]; }});\n\"\".split(p);\nreturn get[0] === Symbol.split && get[1] === Symbol.toPrimitive && get.length === 2;"
      },
      {
        "name": "Date.prototype.toJSON",
        "exec": "// Date.prototype.toJSON -> ToPrimitive -> Get -> [[Get]]\n// Date.prototype.toJSON -> Invoke -> GetMethod -> GetV -> [[Get]]\nvar get = [];\nvar p = new Proxy({toString:Function(),toISOString:Function()}, { get: function(o, k) { get.push(k); return o[k]; }});\nDate.prototype.toJSON.call(p);\nreturn get[0] === Symbol.toPrimitive && get.slice(1) + '' === \"valueOf,toString,toISOString\";"
      }
    ]
  },
  {
    "name": "Proxy, internal 'set' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/set",
    "subtests": [
      {
        "name": "Object.assign",
        "exec": "// Object.assign -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\nObject.assign(p, { foo: 1, bar: 2 });\nreturn set + '' === \"foo,bar\";"
      },
      {
        "name": "Array.from",
        "exec": "// Array.from -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\nArray.from.call(function(){ return p; }, {length:2, 0:1, 1:2});\nreturn set + '' === \"length\";"
      },
      {
        "name": "Array.of",
        "exec": "// Array.from -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy({}, { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\nArray.of.call(function(){ return p; }, 1, 2, 3);\nreturn set + '' === \"length\";"
      },
      {
        "name": "Array.prototype.copyWithin",
        "exec": "// Array.prototype.copyWithin -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([1,2,3,4,5,6], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.copyWithin(0, 3);\nreturn set + '' === \"0,1,2\";"
      },
      {
        "name": "Array.prototype.fill",
        "exec": "// Array.prototype.fill -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([1,2,3,4,5,6], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.fill(0, 3);\nreturn set + '' === \"3,4,5\";"
      },
      {
        "name": "Array.prototype.pop",
        "exec": "// Array.prototype.pop -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.pop();\nreturn set + '' === \"length\";"
      },
      {
        "name": "Array.prototype.push",
        "exec": "// Array.prototype.push -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.push(0,0,0);\nreturn set + '' === \"0,1,2,length\";"
      },
      {
        "name": "Array.prototype.reverse",
        "exec": "// Array.prototype.reverse -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([0,0,0,,], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.reverse();\nreturn set + '' === \"3,1,2\";"
      },
      {
        "name": "Array.prototype.shift",
        "exec": "// Array.prototype.shift -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([0,0,,0], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.shift();\nreturn set + '' === \"0,2,length\";"
      },
      {
        "name": "Array.prototype.splice",
        "exec": "// Array.prototype.splice -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([1,2,3], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.splice(1,0,0);\nreturn set + '' === \"3,2,1,length\";"
      },
      {
        "name": "Array.prototype.unshift",
        "exec": "// Array.prototype.unshift -> Set -> [[Set]]\nvar set = [];\nvar p = new Proxy([0,0,,0], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});\np.unshift(0,1);\nreturn set + '' === \"5,3,2,0,1,length\";"
      }
    ]
  },
  {
    "name": "Proxy, internal 'defineProperty' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/defineProperty",
    "subtests": [
      {
        "name": "[[Set]]",
        "exec": "// [[Set]] -> [[DefineOwnProperty]]\nvar def = [];\nvar p = new Proxy({foo:1, bar:2}, { defineProperty: function(o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; }});\np.foo = 2; p.bar = 4;\nreturn def + '' === \"foo,bar\";"
      },
      {
        "name": "SetIntegrityLevel",
        "exec": "// SetIntegrityLevel -> DefinePropertyOrThrow -> [[DefineOwnProperty]]\nvar def = [];\nvar p = new Proxy({foo:1, bar:2}, { defineProperty: function(o, v, desc) { def.push(v); Object.defineProperty(o, v, desc); return true; }});\nObject.freeze(p);\nreturn def + '' === \"foo,bar\";"
      }
    ]
  },
  {
    "name": "Proxy, internal 'deleteProperty' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty",
    "subtests": [
      {
        "name": "Array.prototype.copyWithin",
        "exec": "// Array.prototype.copyWithin -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,0,0,,,,], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.copyWithin(0,3);\nreturn del + '' === \"0,1,2\";"
      },
      {
        "name": "Array.prototype.pop",
        "exec": "// Array.prototype.pop -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,0,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.pop();\nreturn del + '' === \"2\";"
      },
      {
        "name": "Array.prototype.reverse",
        "exec": "// Array.prototype.reverse -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,,2,,4,,], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.reverse();\nreturn del + '' === \"0,4,2\";"
      },
      {
        "name": "Array.prototype.shift",
        "exec": "// Array.prototype.shift -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,,0,,0,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.shift();\nreturn del + '' === \"0,2,5\";"
      },
      {
        "name": "Array.prototype.splice",
        "exec": "// Array.prototype.splice -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,0,0,0,,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.splice(2,2,0);\nreturn del + '' === \"3,5\";"
      },
      {
        "name": "Array.prototype.unshift",
        "exec": "// Array.prototype.unshift -> DeletePropertyOrThrow -> [[Delete]]\nvar del = [];\nvar p = new Proxy([0,0,,0,,0], { deleteProperty: function(o, v) { del.push(v); return delete o[v]; }});\np.unshift(0);\nreturn del + '' === \"5,3\";"
      }
    ]
  },
  {
    "name": "Proxy, internal 'getOwnPropertyDescriptor' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/getOwnPropertyDescriptor",
    "subtests": [
      {
        "name": "[[Set]]",
        "exec": "// [[Set]] -> [[GetOwnProperty]]\nvar gopd = [];\nvar p = new Proxy({},\n  { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }});\np.foo = 1; p.bar = 1;\nreturn gopd + '' === \"foo,bar\";"
      },
      {
        "name": "Object.assign",
        "exec": "// Object.assign -> [[GetOwnProperty]]\nvar gopd = [];\nvar p = new Proxy({foo:1, bar:2},\n  { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }});\nObject.assign({}, p);\nreturn gopd + '' === \"foo,bar\";"
      },
      {
        "name": "Object.prototype.hasOwnProperty",
        "exec": "// Object.prototype.hasOwnProperty -> HasOwnProperty -> [[GetOwnProperty]]\nvar gopd = [];\nvar p = new Proxy({foo:1, bar:2},\n  { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }});\np.hasOwnProperty('garply');\nreturn gopd + '' === \"garply\";"
      },
      {
        "name": "Function.prototype.bind",
        "exec": "// Function.prototype.bind -> HasOwnProperty -> [[GetOwnProperty]]\nvar gopd = [];\nvar p = new Proxy(Function(),\n  { getOwnPropertyDescriptor: function(o, v) { gopd.push(v); return Object.getOwnPropertyDescriptor(o, v); }});\np.bind();\nreturn gopd + '' === \"length\";"
      }
    ]
  },
  {
    "name": "Proxy, internal 'ownKeys' calls",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys",
    "subtests": [
      {
        "name": "SetIntegrityLevel",
        "exec": "// SetIntegrityLevel -> [[OwnPropertyKeys]]\nvar ownKeysCalled = 0;\nvar p = new Proxy({}, { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }});\nObject.freeze(p);\nreturn ownKeysCalled === 1;"
      },
      {
        "name": "TestIntegrityLevel",
        "exec": "// TestIntegrityLevel -> [[OwnPropertyKeys]]\nvar ownKeysCalled = 0;\nvar p = new Proxy(Object.preventExtensions({}), { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }});\nObject.isFrozen(p);\nreturn ownKeysCalled === 1;"
      },
      {
        "name": "SerializeJSONObject",
        "exec": "// SerializeJSONObject -> EnumerableOwnNames -> [[OwnPropertyKeys]]\nvar ownKeysCalled = 0;\nvar p = new Proxy({}, { ownKeys: function(o) { ownKeysCalled++; return Object.keys(o); }});\nJSON.stringify({a:p,b:p});\nreturn ownKeysCalled === 2;"
      }
    ]
  },
  {
    "name": "Object static methods accept primitives",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-object-constructor",
    "subtests": [
      {
        "name": "Object.getPrototypeOf",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getPrototypeOf",
        "exec": "return Object.getPrototypeOf('a').constructor === String;"
      },
      {
        "name": "Object.getOwnPropertyDescriptor",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyDescriptor",
        "exec": "return Object.getOwnPropertyDescriptor('a', 'foo') === void undefined;"
      },
      {
        "name": "Object.getOwnPropertyNames",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames",
        "exec": "var s = Object.getOwnPropertyNames('a');\nreturn s.length === 2 &&\n  ((s[0] === 'length' && s[1] === '0') || (s[0] === '0' && s[1] === 'length'));"
      },
      {
        "name": "Object.seal",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal",
        "exec": "return Object.seal('a') === 'a';"
      },
      {
        "name": "Object.freeze",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze",
        "exec": "return Object.freeze('a') === 'a';"
      },
      {
        "name": "Object.preventExtensions",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/preventExtensions",
        "exec": "return Object.preventExtensions('a') === 'a';"
      },
      {
        "name": "Object.isSealed",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed",
        "exec": "return Object.isSealed('a') === true;"
      },
      {
        "name": "Object.isFrozen",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen",
        "exec": "return Object.isFrozen('a') === true;"
      },
      {
        "name": "Object.isExtensible",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible",
        "exec": "return Object.isExtensible('a') === false;"
      },
      {
        "name": "Object.keys",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys",
        "exec": "var s = Object.keys('a');\nreturn s.length === 1 && s[0] === '0';"
      }
    ]
  },
  {
    "name": "own property order",
    "target": "es6",
    "category": "misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-ordinary-object-internal-methods-and-internal-slots-ownpropertykeys",
    "subtests": [
      {
        "name": "Object.keys",
        "exec": "var obj = {\n  // Non-negative integer names appear first in value order\n  2: true,\n  0: true,\n  1: true,\n  // Other string names appear in source order\n  ' ': true,\n  // Non-negative integers are sorted above other names\n  9: true,\n  D: true,\n  B: true,\n  // Negative integers are treated as other names\n  '-1': true\n};\n// Other string names are added in order of creation\nobj.A = true;\n// Non-negative integer names, conversely, ignore order of creation\nobj[3] = true;\n// Having a total of 20+ properties doesn't affect property order\n\"EFGHIJKLMNOPQRSTUVWXYZ\".split('').forEach(function(key){\n  obj[key] = true;\n});\n// Object.defineProperty doesn't affect the above rules\nObject.defineProperty(obj, 'C', { value: true, enumerable: true });\nObject.defineProperty(obj, '4', { value: true, enumerable: true });\n// Deleting and reinserting a property doesn't preserve its position\ndelete obj[2];\nobj[2] = true;\n\nvar forInOrder = '';\nfor(var key in obj)forInOrder += key;\n\nreturn Object.keys(obj).join('') === forInOrder;"
      },
      {
        "name": "Object.getOwnPropertyNames",
        "exec": "var obj = {\n  2: true,\n  0: true,\n  1: true,\n  ' ': true,\n  9: true,\n  D: true,\n  B: true,\n  '-1': true\n};\nobj.A = true;\nobj[3] = true;\n\"EFGHIJKLMNOPQRSTUVWXYZ\".split('').forEach(function(key){\n  obj[key] = true;\n});\nObject.defineProperty(obj, 'C', { value: true, enumerable: true });\nObject.defineProperty(obj, '4', { value: true, enumerable: true });\ndelete obj[2];\nobj[2] = true;\n\nreturn Object.getOwnPropertyNames(obj).join('') === \"012349 DB-1AEFGHIJKLMNOPQRSTUVWXYZC\";"
      },
      {
        "name": "Object.assign",
        "exec": "var result = '';\nvar target = {};\n\n\"012349 DBACEFGHIJKLMNOPQRST\".split('').concat(-1).forEach(function(key){\n  Object.defineProperty(target, key, {\n    set: function(){\n      result += key;\n    }\n  })\n});\n\nvar obj = {2: 2, 0: 0, 1: 1, ' ': ' ', 9: 9, D: 'D', B: 'B', '-1': '-1'};\nObject.defineProperty(obj, 'A', {value: 'A',  enumerable: true});\nObject.defineProperty(obj, '3', {value: '3',  enumerable: true});\nObject.defineProperty(obj, 'C', {value: 'C',  enumerable: true});\nObject.defineProperty(obj, '4', {value: '4',  enumerable: true});\ndelete obj[2];\nobj[2] = true;\n\n\"EFGHIJKLMNOPQRST\".split('').forEach(function(key){\n  obj[key] = key;\n});\n\nObject.assign(target, obj);\n\nreturn result === \"012349 DB-1ACEFGHIJKLMNOPQRST\";"
      },
      {
        "name": "JSON.stringify",
        "exec": "var obj = {\n  2: true,\n  0: true,\n  1: true,\n  ' ': true,\n  9: true,\n  D: true,\n  B: true,\n  '-1': true\n};\nobj.A = true;\nobj[3] = true;\n\"EFGHIJKLMNOPQRSTUVWXYZ\".split('').forEach(function(key){\n  obj[key] = true;\n});\nObject.defineProperty(obj, 'C', { value: true, enumerable: true });\nObject.defineProperty(obj, '4', { value: true, enumerable: true });\ndelete obj[2];\nobj[2] = true;\n\nreturn JSON.stringify(obj) ===\n  '{\"0\":true,\"1\":true,\"2\":true,\"3\":true,\"4\":true,\"9\":true,\" \":true,\"D\":true,\"B\":true,\"-1\":true,\"A\":true,\"E\":true,\"F\":true,\"G\":true,\"H\":true,\"I\":true,\"J\":true,\"K\":true,\"L\":true,\"M\":true,\"N\":true,\"O\":true,\"P\":true,\"Q\":true,\"R\":true,\"S\":true,\"T\":true,\"U\":true,\"V\":true,\"W\":true,\"X\":true,\"Y\":true,\"Z\":true,\"C\":true}';"
      },
      {
        "name": "JSON.parse",
        "exec": "var result = '';\nJSON.parse(\n  '{\"0\":true,\"1\":true,\"2\":true,\"3\":true,\"4\":true,\"9\":true,\" \":true,\"D\":true,\"B\":true,\"-1\":true,\"E\":true,\"F\":true,\"G\":true,\"H\":true,\"I\":true,\"J\":true,\"K\":true,\"L\":true,\"A\":true,\"C\":true}',\n  function reviver(k,v) {\n    result += k;\n    return v;\n  }\n);\nreturn result === \"012349 DB-1EFGHIJKLAC\";"
      },
      {
        "name": "Reflect.ownKeys, string key order",
        "exec": "var obj = {\n  2: true,\n  0: true,\n  1: true,\n  ' ': true,\n  9: true,\n  D: true,\n  B: true,\n  '-1': true\n};\nobj.A = true;\nobj[3] = true;\n\"EFGHIJKLMNOPQRSTUVWXYZ\".split('').forEach(function(key){\n  obj[key] = true;\n});\nObject.defineProperty(obj, 'C', { value: true, enumerable: true });\nObject.defineProperty(obj, '4', { value: true, enumerable: true });\ndelete obj[2];\nobj[2] = true;\n\nreturn Reflect.ownKeys(obj).join('') === \"012349 DB-1AEFGHIJKLMNOPQRSTUVWXYZC\";"
      },
      {
        "name": "Reflect.ownKeys, symbol key order",
        "exec": "var sym1 = Symbol(), sym2 = Symbol(), sym3 = Symbol();\nvar obj = {\n  1: true,\n  A: true\n};\nobj.B = true;\nobj[sym1] = true;\nobj[2] = true;\nobj[sym2] = true;\nObject.defineProperty(obj, 'C', { value: true, enumerable: true });\nObject.defineProperty(obj, sym3,{ value: true, enumerable: true });\nObject.defineProperty(obj, 'D', { value: true, enumerable: true });\n\nvar result = Reflect.ownKeys(obj);\nvar l = result.length;\nreturn result[l-3] === sym1 && result[l-2] === sym2 && result[l-1] === sym3;"
      }
    ]
  },
  {
    "name": "Updated identifier syntax",
    "target": "es6",
    "category": "misc",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-names-and-keywords",
    "subtests": [
      {
        "name": "var ⸯ;",
        "exec": "try {\n  eval('var ⸯ');\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "var 𐋀;",
        "exec": "var 𐋀;\nreturn true;"
      },
      {
        "name": "no escaped reserved words as identifiers",
        "exec": "var \\u0061;\ntry {\n  eval('var v\\\\u0061r');\n} catch(e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "miscellaneous",
    "target": "es6",
    "category": "misc",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-additions-and-changes-that-introduce-incompatibilities-with-prior-editions",
    "subtests": [
      {
        "name": "duplicate property names in strict mode",
        "exec": "'use strict';\nreturn this === void undefined && ({ a:1, a:1 }).a === 1;"
      },
      {
        "name": "no semicolon needed after do-while",
        "exec": "do {} while (false) return true;"
      },
      {
        "name": "no assignments allowed in for-in head in strict mode",
        "exec": "'use strict';\ntry {\n  eval('for (var i = 0 in {}) {}');\n}\ncatch(e) {\n  return true;\n}"
      },
      {
        "name": "accessors aren't constructors",
        "exec": "var f = (Object.getOwnPropertyDescriptor({get a(){}}, 'a')).get;\ntry {\n  new f;\n} catch(e) {\n  return true;\n}"
      },
      {
        "name": "Invalid Date",
        "exec": "return new Date(NaN) + \"\" === \"Invalid Date\";"
      },
      {
        "name": "RegExp constructor can alter flags",
        "exec": "return new RegExp(/./im, \"g\").global === true;"
      },
      {
        "name": "RegExp.prototype.toString generic and uses \"flags\" property",
        "exec": "return RegExp.prototype.toString.call({source: 'foo', flags: 'bar'}) === '/foo/bar';"
      },
      {
        "name": "built-in prototypes are not instances",
        "exec": "try {\n  RegExp.prototype.exec(); return false;\n} catch(e) {}\ntry {\n  Date.prototype.valueOf(); return false;\n} catch(e) {}\n\nif (![Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError, URIError].every(function (E) {\n    return Object.prototype.toString.call(E.prototype) === '[object Object]';\n})) {\n  return false;\n}\n\nreturn true;"
      },
      {
        "name": "function 'length' is configurable",
        "exec": "var fn = function(a, b) {};\n\nvar desc = Object.getOwnPropertyDescriptor(fn, \"length\");\nif (desc.configurable) {\n  Object.defineProperty(fn, \"length\", { value: 1 });\n  return fn.length === 1;\n}\n\nreturn false;"
      }
    ]
  },
  {
    "name": "non-strict function semantics",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-labelled-function-declarations",
    "subtests": [
      {
        "name": "hoisted block-level function declaration",
        "exec": "// Note: only available outside of strict mode.\nif (!this) return false;\nvar passed = f() === 1;\nfunction f() { return 1; }\n\npassed &= typeof g === 'undefined';\n{ function g() { return 1; } }\npassed &= g() === 1;\n\npassed &= h() === 2;\n{ function h() { return 1; } }\nfunction h() { return 2; }\npassed &= h() === 1;\n\nreturn passed;"
      },
      {
        "name": "labeled function statements",
        "exec": "// Note: only available outside of strict mode.\nif (!this) return false;\n\nlabel: function foo() { return 2; }\nreturn foo() === 2;"
      },
      {
        "name": "function statements in if-statement clauses",
        "exec": "// Note: only available outside of strict mode.\nif (!this) return false;\n\nif(true) function foo() { return 2; }\nif(false) {} else function bar() { return 3; }\nif(true) function baz() { return 4; } else {}\nif(false) function qux() { return 5; } else function qux() { return 6; }\nreturn foo() === 2 && bar() === 3 && baz() === 4 && qux() === 6;"
      }
    ]
  },
  {
    "name": "__proto__ in object literals",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-__proto__-property-names-in-object-initializers",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto#Specifications",
    "subtests": [
      {
        "name": "basic support",
        "exec": "return { __proto__ : [] } instanceof Array\n  && !({ __proto__ : null } instanceof Object);"
      },
      {
        "name": "multiple __proto__ is an error",
        "exec": "try {\n  eval(\"({ __proto__ : [], __proto__: {} })\");\n}\ncatch(e) {\n  return true;\n}"
      },
      {
        "name": "not a computed property",
        "exec": "if (!({ __proto__ : [] } instanceof Array)) {\n  return false;\n}\nvar a = \"__proto__\";\nreturn !({ [a] : [] } instanceof Array);"
      },
      {
        "name": "not a shorthand property",
        "exec": "if (!({ __proto__ : [] } instanceof Array)) {\n  return false;\n}\nvar __proto__ = [];\nreturn !({ __proto__ } instanceof Array);"
      },
      {
        "name": "not a shorthand method",
        "exec": "if (!({ __proto__ : [] } instanceof Array)) {\n  return false;\n}\nreturn !({ __proto__(){} } instanceof Function);"
      }
    ]
  },
  {
    "name": "Object.prototype.__proto__",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-object.prototype.__proto__",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto",
    "subtests": [
      {
        "name": "get prototype",
        "exec": "var A = function(){};\nreturn (new A()).__proto__ === A.prototype;"
      },
      {
        "name": "set prototype",
        "exec": "var o = {};\no.__proto__ = Array.prototype;\nreturn o instanceof Array;"
      },
      {
        "name": "absent from Object.create(null)",
        "exec": "var o = Object.create(null), p = {};\no.__proto__ = p;\nreturn Object.getPrototypeOf(o) !== p;"
      },
      {
        "name": "present in hasOwnProperty()",
        "exec": "return Object.prototype.hasOwnProperty('__proto__');"
      },
      {
        "name": "correct property descriptor",
        "exec": "var desc = Object.getOwnPropertyDescriptor(Object.prototype,\"__proto__\");\nvar A = function(){};\n\nreturn (desc\n  && \"get\" in desc\n  && \"set\" in desc\n  && desc.configurable\n  && !desc.enumerable);"
      },
      {
        "name": "present in Object.getOwnPropertyNames()",
        "exec": "return Object.getOwnPropertyNames(Object.prototype).indexOf('__proto__') > -1;"
      }
    ]
  },
  {
    "name": "String.prototype HTML methods",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-string.prototype.anchor",
    "subtests": [
      {
        "name": "existence",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/prototype#HTML_wrapper_methods",
        "exec": "var i, names = [\"anchor\", \"big\", \"bold\", \"fixed\", \"fontcolor\", \"fontsize\",\n  \"italics\", \"link\", \"small\", \"strike\", \"sub\", \"sup\"];\nfor (i = 0; i < names.length; i++) {\n  if (typeof String.prototype[names[i]] !== 'function') {\n    return false;\n  }\n}\nreturn true;"
      },
      {
        "name": "tags' names are lowercase",
        "exec": "var i, names = [\"anchor\", \"big\", \"bold\", \"fixed\", \"fontcolor\", \"fontsize\",\n  \"italics\", \"link\", \"small\", \"strike\", \"sub\", \"sup\"];\nfor (i = 0; i < names.length; i++) {\n  if (\"\"[names[i]]().toLowerCase() !== \"\"[names[i]]()) {\n    return false;\n  }\n}\nreturn true;"
      },
      {
        "name": "quotes in arguments are escaped",
        "exec": "var i, names = [\"anchor\", \"fontcolor\", \"fontsize\", \"link\"];\nfor (i = 0; i < names.length; i++) {\n  if (\"\"[names[i]]('\"') !== \"\"[names[i]]('&' + 'quot;')) {\n    return false;\n  }\n}\nreturn true;"
      }
    ]
  },
  {
    "name": "RegExp.prototype.compile",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-regexp.prototype.compile",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/compile",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "if (typeof RegExp.prototype.compile !== 'function')\n  return false\nvar rx = /a/;\nrx.compile('b');\nreturn rx.test('b');"
      },
      {
        "name": "returns this",
        "exec": "var rx = /a/;\nreturn rx.compile('b') === rx;"
      }
    ]
  },
  {
    "name": "RegExp syntax extensions",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-regular-expressions-patterns",
    "subtests": [
      {
        "name": "hyphens in character sets",
        "exec": "return /[\\w-_]/.exec(\"-\")[0] === \"-\";"
      },
      {
        "name": "invalid character escapes",
        "exec": "return /\\z/.exec(\"\\\\z\")[0] === \"z\"\n  && /[\\z]/.exec(\"[\\\\z]\")[0] === \"z\";"
      },
      {
        "name": "invalid control-character escapes",
        "exec": "return /\\c2/.exec(\"\\\\c2\")[0] === \"\\\\c2\";"
      },
      {
        "name": "invalid Unicode escapes",
        "exec": "return /\\u1/.exec(\"u1\")[0] === \"u1\"\n  && /[\\u1]/.exec(\"u\")[0] === \"u\";"
      },
      {
        "name": "invalid hexadecimal escapes",
        "exec": "return /\\x1/.exec(\"x1\")[0] === \"x1\"\n  && /[\\x1]/.exec(\"x\")[0] === \"x\";"
      },
      {
        "name": "incomplete patterns and quantifiers",
        "exec": "return /x{1/.exec(\"x{1\")[0] === \"x{1\"\n  && /x]1/.exec(\"x]1\")[0] === \"x]1\";"
      },
      {
        "name": "octal escape sequences",
        "exec": "return /\\041/.exec(\"!\")[0] === \"!\"\n  && /[\\041]/.exec(\"!\")[0] === \"!\";"
      },
      {
        "name": "invalid backreferences become octal escapes",
        "exec": "return /\\41/.exec(\"!\")[0] === \"!\"\n  && /[\\41]/.exec(\"!\")[0] === \"!\";"
      }
    ]
  },
  {
    "name": "HTML-style comments",
    "target": "es6",
    "category": "annex b",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/6.0/#sec-html-like-comments",
    "exec": "--> A comment\n<!-- Another comment\nvar a = 3; <!-- Another comment\nreturn a === 3;"
  },
  {
    "name": "exponentiation (**) operator",
    "target": "es2016",
    "category": "2016 features",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-exp-operator",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators#Exponentiation_(**)",
    "subtests": [
      {
        "name": "basic support",
        "exec": "return 2 ** 3 === 8 && -(5 ** 2) === -25 && (-5) ** 2 === 25;"
      },
      {
        "name": "assignment",
        "exec": "var a = 2; a **= 3; return a === 8;"
      },
      {
        "name": "early syntax error for unary negation without parens",
        "exec": "if (2 ** 3 !== 8) { return false; }\ntry {\n  function (\"-5 ** 2\")();\n} catch (e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "Array.prototype.includes",
    "target": "es2016",
    "category": "2016 features",
    "significance": "small",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-array.prototype.includes",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes",
    "subtests": [
      {
        "name": "Array.prototype.includes",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes",
        "exec": "return [1, 2, 3].includes(1)\n  && ![1, 2, 3].includes(4)\n  && ![1, 2, 3].includes(1, 1)\n  && [NaN].includes(NaN);"
      },
      {
        "name": "Array.prototype.includes handles sparse arrays",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes",
        "exec": "return [,].includes()\n  && Array(1).includes();"
      },
      {
        "name": "Array.prototype.includes is generic",
        "exec": "var passed = 0;\nreturn [].includes.call(\n  {\n    get \"0\"() {\n      passed = NaN;\n      return 'foo';\n    },\n    get \"11\"() {\n      passed += 1;\n      return 0;\n    },\n    get \"19\"() {\n      passed += 1;\n      return 'foo';\n    },\n    get \"21\"() {\n      passed = NaN;\n      return 'foo';\n    },\n    get length() {\n      passed += 1;\n      return 24;\n    }\n  },\n  'foo',\n  6\n) === true && passed === 3;"
      },
      {
        "name": "%TypedArray%.prototype.includes",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/includes",
        "exec": "return [\n  Int8Array,\n  Uint8Array,\n  Uint8ClampedArray,\n  Int16Array,\n  Uint16Array,\n  Int32Array,\n  Uint32Array,\n  Float32Array,\n  Float64Array\n].every(function (TypedArray) {\n  return new TypedArray([1, 2, 3]).includes(1)\n  && !new TypedArray([1, 2, 3]).includes(4)\n  && !new TypedArray([1, 2, 3]).includes(1, 1);\n});"
      }
    ]
  },
  {
    "name": "generator functions can't be used with \"new\"",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-createdynamicfunction",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*#Generators_are_not_constructable",
    "exec": "function * generator() {\n  yield 3;\n}\ntry {\n  new generator();\n} catch (e) {\n  return true;\n}"
  },
  {
    "name": "generator throw() caught by inner generator",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-generatorfunction-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function*#IteratorResult_object_returned_instead_of_throwing",
    "exec": "function * generator() {\n  yield * (function * () {\n    try {\n      yield 'foo';\n    }\n    catch (e) {\n      return;\n    }\n  }());\n  yield 'bar';\n}\nvar iter = generator();\niter.next();\nreturn iter['throw']().value === 'bar';"
  },
  {
    "name": "strict fn w/ non-strict non-simple params is error",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-functiondeclarationinstantiation",
    "exec": "function foo(...a) {}\ntry {\n  function (\"function bar(...a) {'use strict';}\")();\n} catch (e) {\nreturn true;\n}"
  },
  {
    "name": "nested rest destructuring, declarations",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-destructuring-assignment",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Nested_object_and_array_destructuring",
    "exec": "var [x, ...[y, ...z]] = [1,2,3,4];\nreturn x === 1 && y === 2 && z + '' === '3,4';"
  },
  {
    "name": "nested rest destructuring, parameters",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-destructuring-assignment",
    "exec": "return function ([x, ...[y, ...z]]) {\n  return x === 1 && y === 2 && z + '' === '3,4';\n}([1,2,3,4]);"
  },
  {
    "name": "Proxy, \"enumerate\" handler removed",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-proxy-objects",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/enumerate",
    "exec": "var passed = true;\nvar proxy = new Proxy({}, {\n  enumerate: function () {\n    passed = false;\n  }\n});\nfor (var key in proxy); // Should not throw, nor execute the 'enumerate' method.\nreturn passed;"
  },
  {
    "name": "Proxy internal calls, Array.prototype.includes",
    "target": "es2016",
    "category": "2016 misc",
    "significance": "tiny",
    "spec": "http://www.ecma-international.org/ecma-262/7.0/index.html#sec-array.prototype.includes",
    "exec": "// Array.prototype.includes -> Get -> [[Get]]\nvar get = [];\nvar p = new Proxy({length: 3, 0: '', 1: '', 2: '', 3: ''}, { get: function (o, k) { get.push(k); return o[k]; }});\nArray.prototype.includes.call(p, {});\nif (get + '' !== \"length,0,1,2\") return;\n\nget = [];\np = new Proxy({length: 4, 0: NaN, 1: '', 2: NaN, 3: ''}, { get: function (o, k) { get.push(k); return o[k]; }});\nArray.prototype.includes.call(p, NaN, 1);\nreturn (get + '' === \"length,1,2\");"
  },
  {
    "name": "Object static methods",
    "target": "es2016",
    "category": "2017 features",
    "significance": "medium",
    "spec": "https://tc39.github.io/ecma262/#sec-properties-of-the-object-constructor",
    "subtests": [
      {
        "name": "Object.values",
        "category": "2017 features",
        "significance": "medium",
        "spec": "https://tc39.github.io/ecma262/#sec-object.values",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/values",
        "exec": "var obj = Object.create({ a: \"qux\", d: \"qux\" });\nobj.a = \"foo\";\nobj.b = \"bar\";\nobj.c = \"baz\";\nvar v = Object.values(obj);\nreturn Array.isArray(v) && String(v) === \"foo,bar,baz\";"
      },
      {
        "name": "Object.entries",
        "spec": "https://tc39.github.io/ecma262/#sec-object.entries",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries",
        "exec": "var obj = Object.create({ a: \"qux\", d: \"qux\" });\nobj.a = \"foo\";\nobj.b = \"bar\";\nobj.c = \"baz\";\nvar e = Object.entries(obj);\nreturn Array.isArray(e)\n  && e.length === 3\n  && String(e[0]) === \"a,foo\"\n  && String(e[1]) === \"b,bar\"\n  && String(e[2]) === \"c,baz\";"
      },
      {
        "name": "Object.getOwnPropertyDescriptors",
        "spec": "https://tc39.github.io/ecma262/#sec-object.getownpropertydescriptors",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/getOwnPropertyDescriptors",
        "exec": "var object = {a: 1};\nvar B = typeof Symbol === 'function' ? Symbol('b') : 'b';\nobject[B] = 2;\nvar O = Object.defineProperty(object, 'c', {value: 3});\nvar D = Object.getOwnPropertyDescriptors(O);\n\nreturn D.a.value === 1 && D.a.enumerable === true && D.a.configurable === true && D.a.writable === true\n  && D[B].value === 2 && D[B].enumerable === true && D[B].configurable === true && D[B].writable === true\n  && D.c.value === 3 && D.c.enumerable === false && D.c.configurable === false && D.c.writable === false;"
      },
      {
        "name": "Object.getOwnPropertyDescriptors doesn't provide undefined descriptors",
        "exec": "var P = new Proxy({ a: 1 }, {\n  getOwnPropertyDescriptor: function (t, k) {}\n});\nreturn !Object.getOwnPropertyDescriptors(P).hasOwnProperty('a');"
      }
    ]
  },
  {
    "name": "String padding",
    "target": "es2016",
    "category": "2017 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-string-pad-start-end",
    "subtests": [
      {
        "name": "String.prototype.padStart",
        "spec": "https://tc39.github.io/ecma262/#sec-string.prototype.padstart",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart",
        "exec": "return 'hello'.padStart(10) === '     hello'\n  && 'hello'.padStart(10, '1234') === '12341hello'\n  && 'hello'.padStart() === 'hello'\n  && 'hello'.padStart(6, '123') === '1hello'\n  && 'hello'.padStart(3) === 'hello'\n  && 'hello'.padStart(3, '123') === 'hello';"
      },
      {
        "name": "String.prototype.padEnd",
        "spec": "https://tc39.github.io/ecma262/#sec-string.prototype.padend",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd",
        "exec": "return 'hello'.padEnd(10) === 'hello     '\n  && 'hello'.padEnd(10, '1234') === 'hello12341'\n  && 'hello'.padEnd() === 'hello'\n  && 'hello'.padEnd(6, '123') === 'hello1'\n  && 'hello'.padEnd(3) === 'hello'\n  && 'hello'.padEnd(3, '123') === 'hello';"
      }
    ]
  },
  {
    "name": "trailing commas in function syntax",
    "target": "es2016",
    "category": "2017 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-trailing-function-commas",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Trailing_commas",
    "subtests": [
      {
        "name": "in parameter lists",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Trailing_commas#Parameter_definitions",
        "exec": "return typeof function f( a, b, ) {} === 'function';"
      },
      {
        "name": "in argument lists",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Trailing_commas#Function_calls",
        "exec": "return Math.min(1,2,3,) === 1;"
      }
    ]
  },
  {
    "name": "async functions",
    "target": "es2016",
    "category": "2017 features",
    "significance": "large",
    "spec": "https://tc39.github.io/ecma262/#sec-async-function-definitions",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function",
    "subtests": [
      {
        "name": "return",
        "exec": "async function a() {\n  return \"foo\";\n}\nvar p = a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.then(function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      },
      {
        "name": "throw",
        "exec": "async function a() {\n  throw \"foo\";\n}\nvar p = a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.catch (function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      },
      {
        "name": "no line break between async and function",
        "exec": "async function a() {}\ntry { function (\"async\\n function a() {await 0}\")(); } catch (e) { return true; }"
      },
      {
        "name": "no \"prototype\" property",
        "exec": "async function a() {};\nreturn !a.hasOwnProperty(\"prototype\");"
      },
      {
        "name": "await",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await",
        "exec": "(async function () {\n  await Promise.resolve();\n  var a1 = await new Promise(function (resolve) { setTimeout(resolve,800,\"foo\"); });\n  var a2 = await new Promise(function (resolve) { setTimeout(resolve,800,\"bar\"); });\n  if (a1 + a2 === \"foobar\") {\n    asyncTestPassed();\n  }\n}());"
      },
      {
        "name": "await, rejection",
        "exec": "(async function () {\n  await Promise.resolve();\n  try {\n    var a1 = await new Promise(function (_, reject) { setTimeout(reject,800,\"foo\"); });\n  } catch (e) {\n    if (e === \"foo\") {\n      asyncTestPassed();\n    }\n  }\n}());"
      },
      {
        "name": "must await a value",
        "exec": "async function a() { await Promise.resolve(); }\ntry { function (\"(async function a() { await; }())\")(); } catch (e) { return true; }"
      },
      {
        "name": "can await non-Promise values",
        "exec": "(async function () {\n  await Promise.resolve();\n  var e = await \"foo\";\n  if (e === \"foo\") {\n    asyncTestPassed();\n  }\n}());"
      },
      {
        "name": "cannot await in parameters",
        "exec": "async function a() { await Promise.resolve(); }\ntry { function (\"(async function a(b = await Promise.resolve()) {}())\")(); } catch (e) { return true; }"
      },
      {
        "name": "async methods, object literals",
        "exec": "var o = {\n  async a() { return await Promise.resolve(\"foo\"); }\n};\nvar p = o.a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.then(function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      },
      {
        "name": "async methods, classes",
        "exec": "class C {\n  async a() { return await Promise.resolve(\"foo\"); }\n};\nvar p = new C().a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.then(function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      },
      {
        "name": "async arrow functions in methods, classes",
        "exec": "function doSomething(callback) {\n  callback();\n}\nclass C {\n  a() {\n    doSomething(async () => {\n      await 1;\n      asyncTestPassed();\n    });\n  }\n};\nvar p = new C().a();"
      },
      {
        "name": "async arrow functions",
        "exec": "var a = async () => await Promise.resolve(\"foo\");\nvar p = a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.then(function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      },
      {
        "name": "correct prototype chain",
        "exec": "var asyncFunctionProto = Object.getPrototypeOf(async function () {});\nreturn asyncFunctionProto !== function () {}.prototype\n  && Object.getPrototypeOf(asyncFunctionProto) === Function.prototype;"
      },
      {
        "name": "async function prototype, Symbol.toStringTag",
        "exec": "return Object.getPrototypeOf(async function () {})[Symbol.toStringTag] === \"AsyncFunction\";"
      },
      {
        "name": "async function constructor",
        "exec": "var a = async function () {}.constructor(\"return 'foo';\");\nvar p = a();\nif (!(p instanceof Promise)) {\n  return false;\n}\np.then(function (result) {\n  if (result === \"foo\") {\n    asyncTestPassed();\n  }\n});"
      }
    ]
  },
  {
    "name": "shared memory and atomics",
    "target": "es2016",
    "category": "2017 features",
    "significance": "medium",
    "subtests": [
      {
        "name": "SharedArrayBuffer",
        "spec": "https://tc39.github.io/ecma262/#sec-sharedarraybuffer-objects",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer",
        "exec": "return typeof SharedArrayBuffer === 'function';"
      },
      {
        "name": "SharedArrayBuffer[Symbol.species]",
        "exec": "return SharedArrayBuffer[Symbol.species] === SharedArrayBuffer;"
      },
      {
        "name": "SharedArrayBuffer.prototype.byteLength",
        "spec": "https://tc39.github.io/ecma262/#sec-get-sharedarraybuffer.prototype.bytelength",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer/byteLength",
        "exec": "return 'byteLength' in SharedArrayBuffer.prototype;"
      },
      {
        "name": "SharedArrayBuffer.prototype.slice",
        "spec": "https://tc39.github.io/ecma262/#sec-sharedarraybuffer.prototype.slice",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer/slice",
        "exec": "return typeof SharedArrayBuffer.prototype.slice === 'function';"
      },
      {
        "name": "SharedArrayBuffer.prototype[Symbol.toStringTag]",
        "spec": "https://tc39.github.io/ecma262/#sec-sharedarraybuffer.prototype.toString",
        "exec": "return SharedArrayBuffer.prototype[Symbol.toStringTag] === 'SharedArrayBuffer';"
      },
      {
        "name": "Atomics.add",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.add",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/add",
        "exec": "return typeof Atomics.add === 'function';"
      },
      {
        "name": "Atomics.and",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.and",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/and",
        "exec": "return typeof Atomics.and === 'function';"
      },
      {
        "name": "Atomics.compareExchange",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.compareExchange",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/compareExchange",
        "exec": "return typeof Atomics.compareExchange === 'function';"
      },
      {
        "name": "Atomics.exchange",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.exchange",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/exchange",
        "exec": "return typeof Atomics.exchange === 'function';"
      },
      {
        "name": "Atomics.wait",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.wait",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/wait",
        "exec": "return typeof Atomics.wait === 'function';"
      },
      {
        "name": "Atomics.notify",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.notify",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/notify",
        "exec": "return typeof Atomics.notify === 'function';"
      },
      {
        "name": "Atomics.isLockFree",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.isLockFree",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/isLockFree",
        "exec": "return typeof Atomics.isLockFree === 'function';"
      },
      {
        "name": "Atomics.load",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.load",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/load",
        "exec": "return typeof Atomics.load === 'function';"
      },
      {
        "name": "Atomics.or",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.or",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/or",
        "exec": "return typeof Atomics.or === 'function';"
      },
      {
        "name": "Atomics.store",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.store",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/store",
        "exec": "return typeof Atomics.store === 'function';"
      },
      {
        "name": "Atomics.sub",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.sub",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/sub",
        "exec": "return typeof Atomics.sub === 'function';"
      },
      {
        "name": "Atomics.xor",
        "spec": "https://tc39.github.io/ecma262/#sec-atomics.xor",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/xor",
        "exec": "return typeof Atomics.xor === 'function';"
      }
    ]
  },
  {
    "name": "RegExp \"u\" flag, case folding",
    "target": "es2016",
    "category": "2017 misc",
    "significance": "tiny",
    "spec": "https://github.com/tc39/ecma262/pull/525",
    "exec": "return \"ſ\".match(/\\w/iu) && !\"ſ\".match(/\\W/iu)\n  && \"\\u212a\".match(/\\w/iu) && !\"\\u212a\".match(/\\W/iu)\n  && \"\\u212a\".match(/.\\b/iu) && \"ſ\".match(/.\\b/iu)\n  && !\"\\u212a\".match(/.\\B/iu) && !\"ſ\".match(/.\\B/iu);"
  },
  {
    "name": "arguments.caller removed",
    "target": "es2016",
    "category": "2017 misc",
    "significance": "tiny",
    "spec": "https://github.com/tc39/ecma262/pull/689",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments/caller",
    "exec": "return (function () {\n  'use strict';\n  return !Object.getOwnPropertyDescriptor(arguments, 'caller');\n})();"
  },
  {
    "name": "Object.prototype getter/setter methods",
    "target": "es2016",
    "category": "2017 annex b",
    "significance": "tiny",
    "spec": "https://tc39.github.io/ecma262/#sec-object.prototype.__defineGetter__",
    "subtests": [
      {
        "name": "__defineGetter__",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__defineGetter__",
        "exec": "var obj = {};\nfunction bar() { return \"bar\"; }\nObject.prototype.__defineGetter__.call(obj, \"foo\", bar);\nvar prop = Object.getOwnPropertyDescriptor(obj, \"foo\");\nreturn prop.get === bar && !prop.writable && prop.configurable\n&& prop.enumerable;"
      },
      {
        "name": "__defineGetter__, symbols",
        "exec": "var obj = {};\nvar sym = Symbol();\nfunction bar() { return \"bar\"; }\nObject.prototype.__defineGetter__.call(obj, sym, bar);\nvar prop = Object.getOwnPropertyDescriptor(obj, sym);\nreturn prop.get === bar && !prop.writable && prop.configurable\n&& prop.enumerable;"
      },
      {
        "name": "__defineGetter__, ToObject(this)",
        "exec": "var key = '__accessors_test__';\n__defineGetter__.call(1, key, function () {});\ntry {\n  __defineGetter__.call(null, key, function () {});\n} catch (e) {\nreturn true;\n}"
      },
      {
        "name": "__defineSetter__",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__defineSetter__",
        "exec": "var obj = {};\nfunction bar() {}\nObject.prototype.__defineSetter__.call(obj, \"foo\", bar);\nvar prop = Object.getOwnPropertyDescriptor(obj, \"foo\");\nreturn prop.set === bar && !prop.writable && prop.configurable\n&& prop.enumerable;"
      },
      {
        "name": "__defineSetter__, symbols",
        "exec": "var obj = {};\nvar sym = Symbol();\nfunction bar(baz) {}\nObject.prototype.__defineSetter__.call(obj, sym, bar);\nvar prop = Object.getOwnPropertyDescriptor(obj, sym);\nreturn prop.set === bar && !prop.writable && prop.configurable\n&& prop.enumerable;"
      },
      {
        "name": "__defineSetter__, ToObject(this)",
        "exec": "var key = '__accessors_test__';\n__defineSetter__.call(1, key, function () {});\ntry {\n__defineSetter__.call(null, key, function () {});\n} catch (e) {\nreturn true;\n}"
      },
      {
        "name": "__lookupGetter__",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__lookupGetter__",
        "exec": "var obj = {\nget foo() { return \"bar\"},\nqux: 1\n};\nvar foo = Object.prototype.__lookupGetter__.call(obj, \"foo\");\nreturn foo() === \"bar\"\n&& Object.prototype.__lookupGetter__.call(obj, \"qux\") === void undefined\n&& Object.prototype.__lookupGetter__.call(obj, \"baz\") === void undefined;"
      },
      {
        "name": "__lookupGetter__, prototype chain",
        "exec": "var obj = {\nget foo() { return \"bar\"},\nqux: 1\n};\nvar foo = Object.prototype.__lookupGetter__.call(Object.create(obj), \"foo\");\nreturn foo() === \"bar\"\n&& Object.prototype.__lookupGetter__.call(obj, \"qux\") === void undefined\n&& Object.prototype.__lookupGetter__.call(obj, \"baz\") === void undefined;"
      },
      {
        "name": "__lookupGetter__, symbols",
        "exec": "var sym = Symbol();\nvar sym2 = Symbol();\nvar obj = {};\nObject.defineProperty(obj, sym, { get: function () { return \"bar\"; }});\nObject.defineProperty(obj, sym2, { value: 1 });\nvar foo = Object.prototype.__lookupGetter__.call(obj, sym);\nreturn foo() === \"bar\"\n  && Object.prototype.__lookupGetter__.call(obj, sym2) === void undefined\n  && Object.prototype.__lookupGetter__.call(obj, Symbol()) === void undefined;"
      },
      {
        "name": "__lookupGetter__, ToObject(this)",
        "exec": "__lookupGetter__.call(1, 'key');\ntry {\n  __lookupGetter__.call(null, 'key');\n} catch (e) {\n  return true;\n}"
      },
      {
        "name": "__lookupGetter__, data properties can shadow accessors",
        "exec": "var a = {};\nvar b = Object.create(a);\nb.foo = 1;\na.__defineGetter__(\"foo\", function () {});\nreturn b.__lookupGetter__(\"foo\") === void undefined;"
      },
      {
        "name": "__lookupSetter__",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__lookupSetter__",
        "exec": "var obj = {\n  set foo(baz) { return \"bar\"; },\n  qux: 1\n};\nvar foo = Object.prototype.__lookupSetter__.call(obj, \"foo\");\nreturn foo() === \"bar\"\n  && Object.prototype.__lookupSetter__.call(obj, \"qux\") === void undefined\n  && Object.prototype.__lookupSetter__.call(obj, \"baz\") === void undefined;"
      },
      {
        "name": "__lookupSetter__, prototype chain",
        "exec": "var obj = {\n  set foo(baz) { return \"bar\"; },\n  qux: 1\n};\nvar foo = Object.prototype.__lookupSetter__.call(Object.create(obj), \"foo\");\nreturn foo() === \"bar\"\n  && Object.prototype.__lookupSetter__.call(obj, \"qux\") === void undefined\n  && Object.prototype.__lookupSetter__.call(obj, \"baz\") === void undefined;"
      },
      {
        "name": "__lookupSetter__, symbols",
        "exec": "var sym = Symbol();\nvar sym2 = Symbol();\nvar obj = {};\nObject.defineProperty(obj, sym, { set: function (baz) { return \"bar\"; }});\nObject.defineProperty(obj, sym2, { value: 1 });\nvar foo = Object.prototype.__lookupSetter__.call(obj, sym);\nreturn foo() === \"bar\"\n  && Object.prototype.__lookupSetter__.call(obj, sym2) === void undefined\n  && Object.prototype.__lookupSetter__.call(obj, Symbol()) === void undefined;"
      },
      {
        "name": "__lookupSetter__, ToObject(this)",
        "exec": "__lookupSetter__.call(1, 'key');\ntry {\n  __lookupSetter__.call(null, 'key');\n} catch (e) {\n  return true;\n}"
      },
      {
        "name": "__lookupSetter__, data properties can shadow accessors",
        "exec": "var a = {};\nvar b = Object.create(a);\nb.foo = 1;\na.__defineSetter__(\"foo\", function () {})\nreturn b.__lookupSetter__(\"foo\") === void undefined"
      }
    ]
  },
  {
    "name": "Proxy internal calls, getter/setter methods",
    "target": "es2016",
    "category": "2017 annex b",
    "significance": "tiny",
    "spec": "https://tc39.github.io/ecma262/#sec-object.prototype.__defineGetter__",
    "subtests": [
      {
        "name": "__defineGetter__",
        "exec": "// Object.prototype.__defineGetter__ -> DefinePropertyOrThrow -> [[DefineOwnProperty]]\nvar def = [];\nvar p = new Proxy({}, {\n  defineProperty: function (o, v, desc) {\n    def.push(v);\n    Object.defineProperty(o, v, desc);\n    return true;\n  }\n});\nObject.prototype.__defineGetter__.call(p, \"foo\", Object);\nreturn def + '' === \"foo\";"
      },
      {
        "name": "__defineSetter__",
        "exec": "// Object.prototype.__defineSetter__ -> DefinePropertyOrThrow -> [[DefineOwnProperty]]\nvar def = [];\nvar p = new Proxy({}, {\n  defineProperty: function (o, v, desc) {\n    def.push(v);\n    Object.defineProperty(o, v, desc);\n    return true;\n  }\n});\nObject.prototype.__defineSetter__.call(p, \"foo\", Object);\nreturn def + '' === \"foo\";"
      },
      {
        "name": "__lookupGetter__",
        "exec": "// Object.prototype.__lookupGetter__ -> [[GetOwnProperty]]\n// Object.prototype.__lookupGetter__ -> [[GetPrototypeOf]]\nvar gopd = [];\nvar gpo = false;\nvar p = new Proxy({}, {\n  getPrototypeOf: function (o) {\n    gpo = true;\n    return Object.getPrototypeOf(o);\n  },\n  getOwnPropertyDescriptor: function (o, v) {\n    gopd.push(v);\n    return Object.getOwnPropertyDescriptor(o, v);\n  }\n});\nObject.prototype.__lookupGetter__.call(p, \"foo\");\nreturn gopd + '' === \"foo\" && gpo;"
      },
      {
        "name": "__lookupSetter__",
        "exec": "// Object.prototype.__lookupSetter__ -> [[GetOwnProperty]]\n// Object.prototype.__lookupSetter__ -> [[GetPrototypeOf]]\nvar gopd = [];\nvar gpo = false;\nvar p = new Proxy({}, {\n  getPrototypeOf: function (o) {\n    gpo = true;\n    return Object.getPrototypeOf(o);\n  },\n  getOwnPropertyDescriptor: function (o, v) {\n    gopd.push(v);\n    return Object.getOwnPropertyDescriptor(o, v);\n  }\n});\nObject.prototype.__lookupSetter__.call(p, \"foo\");\nreturn gopd + '' === \"foo\" && gpo;"
      }
    ]
  },
  {
    "name": "assignments allowed in for-in head in non-strict mode",
    "target": "es2016",
    "category": "2017 annex b",
    "significance": "tiny",
    "spec": "https://tc39.github.io/ecma262/#sec-initializers-in-forin-statement-heads",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in#Compatibility_Initializer_expressions_in_strict_mode",
    "exec": "for (var i = 0 in {}) {}\nreturn i === 0;"
  },
  {
    "name": "object rest/spread properties",
    "target": "es2016",
    "category": "2018 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-object-rest-spread",
    "subtests": [
      {
        "name": "object rest properties",
        "exec": "var { a, ...rest } = { a: 1, b: 2, c: 3 };\nreturn a === 1 && rest.a === void undefined && rest.b === 2 && rest.c === 3;"
      },
      {
        "name": "object spread properties",
        "exec": "var spread = { b: 2, c: 3 };\nvar O = { a: 1, ...spread };\nreturn O !== spread && (O.a + O.b + O.c) === 6;"
      }
    ]
  },
  {
    "name": "Promise.prototype.finally",
    "target": "es2016",
    "category": "2018 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-promise-finally",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/finally",
    "subtests": [
      {
        "name": "basic support",
        "exec": "var p1 = Promise.resolve(\"foo\");\nvar p2 = Promise.reject(\"bar\");\nvar score = 0;\nfunction thenFn(result) {\n  score += (result === \"foo\");\n  check();\n}\nfunction catchFn(result) {\n  score += (result === \"bar\");\n  check();\n}\nfunction finallyFn() {\n  score += (arguments.length === 0);\n  check();\n}\np1.then(thenFn);\np1.finally(finallyFn);\np1.finally(function () {\n  // should return a new Promise\n  score += p1.finally() !== p1;\n  check();\n});\np2.catch (catchFn);\np2.finally(finallyFn);\nfunction check() {\n  if (score === 5) asyncTestPassed();\n}"
      },
      {
        "name": "don't change resolution value",
        "exec": "var score = 0;\nfunction thenFn(result)  {\n  score += (result === \"foo\");\n  check();\n}\nfunction catchFn(result) {\n  score += (result === \"bar\");\n  check();\n}\nfunction finallyFn() {\n  score++;\n  check();\n  return Promise.resolve(\"foobar\");\n}\nPromise.resolve(\"foo\").finally(finallyFn).then(thenFn);\nPromise.reject(\"bar\").finally(finallyFn).catch(catchFn);\nfunction check() {\n  if (score === 4) asyncTestPassed();\n}"
      },
      {
        "name": "change rejection value",
        "exec": "var score = 0;\nPromise\n  .reject(\"foobar\")\n  .finally(function () {\n    return Promise.reject(\"foo\");\n  })\n  .catch (function (result) {\n    score += (result === \"foo\");\n    check();\n    return Promise.reject(\"foobar\");\n  })\n  .finally(function () {\n    throw new Error('bar');\n  })\n  .catch (function (result) {\n    score += (result.message === \"bar\");\n    check();\n  });\nfunction check() {\n  if (score === 2) asyncTestPassed();\n}"
      }
    ]
  },
  {
    "name": "s (dotAll) flag for regular expressions",
    "target": "es2016",
    "category": "2018 features",
    "significance": "small",
    "spec": "https://tc39.github.io/ecma262/#sec-get-regexp.prototype.dotAll",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/dotAll",
    "exec": "const regex = /foo.bar/s;\nreturn regex.test('foo\\nbar');"
  },
  {
    "name": "RegExp named capture groups",
    "target": "es2016",
    "category": "2018 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-named-groups",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Groups_and_Ranges",
    "exec": "var result = /(?<year>\\d{4})-(?<month>\\d{2})-(?<day>\\d{2})/.exec('2016-03-11');\nreturn result.groups.year === '2016'\n  && result.groups.month === '03'\n  && result.groups.day === '11'\n  && result[0] === '2016-03-11'\n  && result[1] === '2016'\n  && result[2] === '03'\n  && result[3] === '11';"
  },
  {
    "name": "RegExp Lookbehind Assertions",
    "target": "es2016",
    "category": "2018 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-lookbehind",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Assertions",
    "exec": "return /(?<=a)b/.test('ab') && /(?<!a)b/.test('cb') &&\n       !/(?<=a)b/.test('b');"
  },
  {
    "name": "RegExp Unicode Property Escapes",
    "target": "es2016",
    "category": "2018 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-unicode-property-escapes",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Unicode_Property_Escapes",
    "subtests": [
      {
        "name": "basic",
        "exec": "const regexGreekSymbol = /\\p{Script=Greek}/u;\nreturn regexGreekSymbol.test('π');"
      },
      {
        "name": "Unicode 11",
        "exec": "return /\\p{Extended_Pictographic}/u.test(\"\\xA9\") && /\\p{Emoji}/u.test(\"🥰\");"
      },
      {
        "name": "Unicode 12",
        "exec": "return /\\p{Script=Elymaic}/u.test(\"\\u{10fe0}\") && /\\p{Emoji}/u.test(\"🥱\");"
      },
      {
        "name": "Unicode 12.1",
        "exec": "return /\\p{Other_Symbol}/u.test(\"\\u32FF\");"
      },
      {
        "name": "Unicode 13",
        "exec": "return /\\p{Script=Chorasmian}/u.test(\"\\u{10fb0}\") && /\\p{Emoji}/u.test(\"🥲\");"
      },
      {
        "name": "Unicode 14",
        "exec": "return /\\p{Script=Vithkuqi}/u.test(\"\\u{10570}\") && /\\p{Emoji}/u.test(\"🫠\");"
      },
      {
        "name": "Unicode 15",
        "exec": "return /\\p{Script=Kawi}/u.test(\"\\u{11f00}\") && /\\p{Emoji}/u.test(\"🫨\");"
      },
      {
        "name": "Unicode 15.1",
        "exec": "return /\\p{Unified_Ideograph}/u.test(\"\\u{2ebf0}\");"
      },
      {
        "name": "Unicode 16.0",
        "exec": "return /\\p{Script=Todhri}/u.test(\"\\u{105c0}\") && /\\p{Emoji}/u.test(\"🫩\");"
      }
    ]
  },
  {
    "name": "Asynchronous Iterators",
    "target": "es2016",
    "category": "2018 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-async-iteration",
    "subtests": [
      {
        "name": "async generators",
        "exec": "async function*generator() {\n  yield 42;\n}\n\nvar iterator = generator();\niterator.next().then(function (step) {\n  if(iterator[Symbol.asyncIterator]() === iterator && step.done === false && step.value === 42)asyncTestPassed();\n});"
      },
      {
        "name": "for-await-of loops",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for-await...of",
        "exec": "var asyncIterable = {};\nasyncIterable[Symbol.asyncIterator] = function () {\n  var i = 0;\n  return {\n    next: function () {\n      switch(++i) {\n        case 1: return Promise.resolve({done: false, value: 'a'});\n        case 2: return Promise.resolve({done: false, value: 'b'});\n      } return Promise.resolve({done: true});\n    }\n  };\n};\n\n(async function () {\n  var result = '';\n  for await(var value of asyncIterable)result += value;\n  if(result === 'ab')asyncTestPassed();\n})();"
      }
    ]
  },
  {
    "name": "Proxy \"ownKeys\" handler, duplicate keys for non-extensible targets",
    "target": "es2016",
    "category": "2018 misc",
    "significance": "tiny",
    "spec": "https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys",
    "exec": "var p = new Proxy({}, {\n  ownKeys() {\n    return [\"a\", \"a\"];\n  }\n});\ntry {\n  Object.keys(p);\n} catch (e) {\n  return e instanceof TypeError;\n}\nreturn false;"
  },
  {
    "name": "template literal revision",
    "target": "es2016",
    "category": "2018 misc",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-template-literal-revision",
    "exec": "function tag(strings, a) {\n  return strings[0] === void undefined\n    && strings.raw[0] === \"\\\\01\\\\1\\\\xg\\\\xAg\\\\u0\\\\u0g\\\\u00g\\\\u000g\\\\u{g\\\\u{0\\\\u{110000}\"\n    && strings[1] === \"\\0\"\n    && strings.raw[1] === \"\\\\0\"\n    && a === 0;\n}\nreturn tag`\\01\\1\\xg\\xAg\\u0\\u0g\\u00g\\u000g\\u{g\\u{0\\u{110000}${0}\\0`;"
  },
  {
    "name": "Symbol.prototype.description",
    "target": "es2016",
    "category": "2019 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-Symbol-description",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/description",
    "subtests": [
      {
        "name": "basic",
        "exec": "return Symbol('foo').description === 'foo';"
      },
      {
        "name": "empty description",
        "exec": "return Symbol('').description === '';"
      },
      {
        "name": "undefined description",
        "exec": "return Symbol.prototype.hasOwnProperty('description')\n  && Symbol().description === void undefined;"
      }
    ]
  },
  {
    "name": "Object.fromEntries",
    "target": "es2016",
    "category": "2019 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-object-from-entries",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries",
    "exec": "var object = Object.fromEntries(new Map([['foo', 42], ['bar', 23]]));\nreturn object.foo === 42 && object.bar === 23;"
  },
  {
    "name": "string trimming",
    "target": "es2016",
    "category": "2019 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-string-left-right-trim",
    "subtests": [
      {
        "name": "String.prototype.trimLeft",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/TrimLeft",
        "exec": "return ' \\t \\n abc   \\t\\n'.trimLeft() === 'abc   \\t\\n';"
      },
      {
        "name": "String.prototype.trimRight",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/TrimRight",
        "exec": "return ' \\t \\n abc   \\t\\n'.trimRight() === ' \\t \\n abc';"
      },
      {
        "name": "String.prototype.trimStart",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimStart",
        "exec": "return ' \\t \\n abc   \\t\\n'.trimStart() === 'abc   \\t\\n';"
      },
      {
        "name": "String.prototype.trimEnd",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimEnd",
        "exec": "return ' \\t \\n abc   \\t\\n'.trimEnd() === ' \\t \\n abc';"
      }
    ]
  },
  {
    "name": "Array.prototype.{flat, flatMap}",
    "target": "es2016",
    "category": "2019 features",
    "significance": "medium",
    "spec": "https://tc39.github.io/proposal-flatMap/",
    "subtests": [
      {
        "name": "Array.prototype.flat",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat",
        "exec": "return [1, [2, 3], [4, [5, 6]]].flat().join('') === '12345,6';"
      },
      {
        "name": "Array.prototype.flatMap",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flatMap",
        "exec": "return [{a: 1, b: 2}, {a: 3, b: 4}].flatMap(function (it) {\n  return [it.a, it.b];\n}).join('') === '1234';"
      },
      {
        "name": "flat and flatMap in Array.prototype[@@unscopables]",
        "exec": "return Array.prototype[Symbol.unscopables].flat\n  && Array.prototype[Symbol.unscopables].flatMap;"
      }
    ]
  },
  {
    "name": "optional catch binding",
    "target": "es2016",
    "category": "2019 misc",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-optional-catch-binding",
    "subtests": [
      {
        "name": "basic",
        "exec": "try {\n  throw new Error();\n}\ncatch {\n  return true;\n}\nreturn false;"
      },
      {
        "name": "await",
        "exec": "(async function () {\n  try {\n    await Promise.reject();\n  }\n  catch {\n    asyncTestPassed();\n  }\n})();"
      },
      {
        "name": "yield",
        "exec": "function *foo() {\n  try {\n    yield;\n  }\n  catch {\n    return true;\n  }\n}\n\nvar it = foo();\nit.next();\nreturn it.throw().value;"
      }
    ]
  },
  {
    "name": "Function.prototype.toString revision",
    "target": "es2016",
    "category": "2019 misc",
    "significance": "small",
    "spec": "https://github.com/tc39/Function-prototype-toString-revision",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/toString",
    "subtests": [
      {
        "name": "functions created with the Function constructor",
        "exec": "var fn = function ('a', ' /\\x2A a \\x2A/ b, c /\\x2A b \\x2A/ //', '/\\x2A c \\x2A/ ; /\\x2A d \\x2A/ //');\nvar str = 'function anonymous(a, /\\x2A a \\x2A/ b, c /\\x2A b \\x2A/ //\\n) {\\n/\\x2A c \\x2A/ ; /\\x2A d \\x2A/ //\\n}';\nreturn fn + '' === str;"
      },
      {
        "name": "arrows",
        "exec": "var str = 'a => b';\nreturn eval('(' + str + ')') + '' === str;"
      },
      {
        "name": "[native code]",
        "exec": "const NATIVE_EVAL_RE = /\\bfunction\\b[\\s\\S]*\\beval\\b[\\s\\S]*\\([\\s\\S]*\\)[\\s\\S]*\\{[\\s\\S]*\\[[\\s\\S]*\\bnative\\b[\\s\\S]+\\bcode\\b[\\s\\S]*\\][\\s\\S]*\\}/;\nreturn NATIVE_EVAL_RE.test(eval + '');"
      },
      {
        "name": "class expression with implicit constructor",
        "exec": "var str = 'class A {}';\nreturn eval('(' + str + ')') + '' === str;"
      },
      {
        "name": "class expression with explicit constructor",
        "exec": "var str = 'class /\\x2A a \\x2A/ A /\\x2A b \\x2A/ extends /\\x2A c \\x2A/ function B() {} /\\x2A d \\x2A/ { /\\x2A e \\x2A/ constructor /\\x2A f \\x2A/ ( /\\x2A g \\x2A/ ) /\\x2A h \\x2A/ { /\\x2A i \\x2A/ ; /\\x2A j \\x2A/ } /\\x2A k \\x2A/ m /\\x2A l \\x2A/ ( /\\x2A m \\x2A/ ) /\\x2A n \\x2A/ { /\\x2A o \\x2A/ } /\\x2A p \\x2A/ }';\nreturn eval('(/\\x2A before \\x2A/' + str + '/\\x2A after \\x2A/)') + '' === str;"
      },
      {
        "name": "unicode escape sequences in identifiers",
        "exec": "var str = 'function \\\\u0061(\\\\u{62}, \\\\u0063) { \\\\u0062 = \\\\u{00063}; return b; }';\nreturn eval('(/\\x2A before \\x2A/' + str + '/\\x2A after \\x2A/)') + '' === str;"
      },
      {
        "name": "methods and computed property names",
        "exec": "var str = '[ /\\x2A a \\x2A/ \"f\" /\\x2A b \\x2A/ ] /\\x2A c \\x2A/ ( /\\x2A d \\x2A/ ) /\\x2A e \\x2A/ { /\\x2A f \\x2A/ }';\nreturn eval('({ /\\x2A before \\x2A/' + str + '/\\x2A after \\x2A/ }.f)') + '' === str;"
      }
    ]
  },
  {
    "name": "JSON superset",
    "target": "es2016",
    "category": "2019 misc",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-json-superset",
    "subtests": [
      {
        "name": "LINE SEPARATOR can appear in string literals",
        "exec": "return eval(\"'\\u2028'\") === \"\\u2028\";"
      },
      {
        "name": "PARAGRAPH SEPARATOR can appear in string literals",
        "exec": "return eval(\"'\\u2029'\") === \"\\u2029\";"
      }
    ]
  },
  {
    "name": "Well-formed JSON.stringify",
    "target": "es2016",
    "category": "2019 misc",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-well-formed-stringify",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#Well-formed_JSON.stringify()",
    "exec": "return JSON.stringify('\\uDF06\\uD834') === \"\\\"\\\\udf06\\\\ud834\\\"\"\n  && JSON.stringify('\\uDEAD') === \"\\\"\\\\udead\\\"\";"
  },
  {
    "name": "String.prototype.matchAll",
    "target": "es2016",
    "category": "2020 features",
    "significance": "small",
    "spec": "https://github.com/tc39/String.prototype.matchAll",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/matchAll",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "var iterator = '11a2bb'.matchAll(/(\\d)(\\D)/g);\nif(iterator[Symbol.iterator]() !== iterator)return false;\nvar a = '', b = '', c = '', step;\nwhile(!(step = iterator.next()).done) {\n  a += step.value[0];\n  b += step.value[1];\n  c += step.value[2];\n}\nreturn a === '1a2b'\n  && b === '12'\n  && c === 'ab';"
      },
      {
        "name": "throws on non-global regex",
        "exec": "if (typeof String.prototype.matchAll !== 'function') return false;\ntry {\n  '11a2bb'.matchAll(/(\\d)(\\D)/);\n} catch (e) {\n  return true;\n}"
      }
    ]
  },
  {
    "name": "BigInt",
    "target": "es2016",
    "category": "2020 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-bigint",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt",
    "subtests": [
      {
        "name": "basic functionality",
        "exec": "return (1n + 2n) === 3n;"
      },
      {
        "name": "constructor",
        "exec": "return BigInt(\"3\") === 3n;"
      },
      {
        "name": "BigInt.asUintN",
        "exec": "return typeof BigInt.asUintN === 'function';"
      },
      {
        "name": "BigInt.asIntN",
        "exec": "return typeof BigInt.asIntN === 'function';"
      },
      {
        "name": "BigInt64Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new BigInt64Array(buffer);\nview[0] = 0x8000000000000000n;\nreturn view[0] === -0x8000000000000000n;"
      },
      {
        "name": "BigUint64Array",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new BigUint64Array(buffer);\nview[0] = 0x10000000000000000n;\nreturn view[0] === 0n;"
      },
      {
        "name": "DataView.prototype.getBigInt64",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setBigInt64(0, 1n);\nreturn view.getBigInt64(0) === 1n;"
      },
      {
        "name": "DataView.prototype.getBigUint64",
        "exec": "var buffer = new ArrayBuffer(64);\nvar view = new DataView(buffer);\nview.setBigUint64(0, 1n);\nreturn view.getBigUint64(0) === 1n;"
      }
    ]
  },
  {
    "name": "Promise.allSettled",
    "target": "es2016",
    "category": "2020 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-promise-allSettled",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/allSettled",
    "exec": "Promise.allSettled([\n  Promise.resolve(1),\n  Promise.reject(2),\n  Promise.resolve(3)\n]).then(it => {\n  if (\n    it.length === 3 &&\n    it[0].status === 'fulfilled' && it[0].value === 1 &&\n    it[1].status === 'rejected' && it[1].reason === 2 &&\n    it[2].status === 'fulfilled' && it[2].value === 3\n  ) asyncTestPassed();\n});"
  },
  {
    "name": "globalThis",
    "target": "es2016",
    "category": "2020 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-global",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis",
    "subtests": [
      {
        "name": "\"globalThis\" global property is global object",
        "exec": "var actualGlobal = function ('return this')();\nactualGlobal.__system_global_test__ = 42;\nreturn typeof globalThis === 'object' && globalThis && globalThis === actualGlobal && !globalThis.lacksGlobalThis && globalThis.__system_global_test__ === 42;"
      },
      {
        "name": "\"globalThis\" global property has correct property descriptor",
        "exec": "var actualGlobal = function ('return this')();\nif (typeof globalThis !== 'object') { return false; }\nif (!('globalThis' in actualGlobal)) { return false; }\nif (Object.prototype.propertyIsEnumerable.call(actualGlobal, 'globalThis')) { return false; }\n\nvar descriptor = Object.getOwnPropertyDescriptor(actualGlobal, 'globalThis');\nreturn descriptor.value === actualGlobal && !descriptor.enumerable && descriptor.configurable && descriptor.writable;"
      }
    ]
  },
  {
    "name": "optional chaining operator (?.)",
    "target": "es2016",
    "category": "2020 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-optional-chaining",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining",
    "subtests": [
      {
        "name": "optional property access",
        "exec": "var foo = { baz: 42 };\nvar bar = null;\nreturn foo?.baz === 42 && bar?.baz === void undefined;"
      },
      {
        "name": "optional bracket access",
        "exec": "var foo = { baz: 42 };\nvar bar = null;\nreturn foo?.['baz'] === 42 && bar?.['baz'] === void undefined;"
      },
      {
        "name": "optional method call",
        "exec": "var foo = { baz: function () { return this.value; }, value: 42 };\nvar bar = null;\nreturn foo?.baz() === 42 && bar?.baz() === void undefined;"
      },
      {
        "name": "optional function call",
        "exec": "var foo = { baz: function () { return 42; } };\nvar bar = {};\nfunction baz() { return 42; };\nvar n;\nreturn foo.baz?.() === 42 && bar.baz?.() === void undefined && baz?.() === 42 && n?.() === void undefined;"
      },
      {
        "name": "spread parameters after optional chaining",
        "exec": "var fn = null;\nvar n = null;\nvar o = {};\n\nreturn fn?.(...[], 1) === void undefined && fn?.(...[], ...[]) === void undefined && o.method?.(...[], 1) === void undefined && n?.method(...[], 1) === void undefined;"
      }
    ]
  },
  {
    "name": "nullish coalescing operator (??)",
    "target": "es2016",
    "category": "2020 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-nullish-coalescing",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator",
    "exec": "return (null ?? 42) === 42 &&\n  (undefined ?? 42) === 42 &&\n  (false ?? 42) === false &&\n  ('' ?? 42) === '' &&\n  (0 ?? 42) === 0 &&\n  isNaN(NaN ?? 42);"
  },
  {
    "name": "String.prototype.replaceAll",
    "target": "es2016",
    "category": "2021 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-string-replace-all",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll",
    "exec": "return 'q=query+string+parameters'.replaceAll('+', ' ') === 'q=query string parameters';"
  },
  {
    "name": "Promise.any",
    "target": "es2016",
    "category": "2021 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-promise-any",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/any",
    "subtests": [
      {
        "name": "fulfillment",
        "exec": "Promise.any([\n  Promise.reject(1),\n  Promise.resolve(2),\n  Promise.resolve(3)\n]).then(it => {\n  if (it === 2) asyncTestPassed();\n});"
      },
      {
        "name": "AggregateError",
        "exec": "Promise.any([\n  Promise.reject(1),\n  Promise.reject(2),\n  Promise.reject(3)\n]).catch (error => {\n  if (error instanceof AggregateError && error.errors.length === 3) asyncTestPassed();\n});"
      }
    ]
  },
  {
    "name": "WeakReferences",
    "target": "es2016",
    "category": "2021 features",
    "significance": "large",
    "spec": "https://github.com/tc39/proposal-weakrefs",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakRef",
    "subtests": [
      {
        "name": "WeakRef minimal support",
        "spec": "https://github.com/tc39/proposal-weakrefs#weak-references",
        "exec": "var O = {};\nvar weakref = new WeakRef(O);\nreturn weakref.deref() === O;"
      },
      {
        "name": "FinalizationRegistry minimal support",
        "spec": "https://github.com/tc39/proposal-weakrefs#finalizers",
        "exec": "var fr = new FinalizationRegistry(function () {});\nreturn Object.getPrototypeOf(fr) === FinalizationRegistry.prototype;"
      }
    ]
  },
  {
    "name": "Logical Assignment",
    "target": "es2016",
    "category": "2021 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-logical-assignment/",
    "subtests": [
      {
        "name": "||= basic support",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_OR_assignment",
        "exec": "let a;\nlet b = 0;\nlet c = 1;\na ||= 2;\nb ||= 2;\nc ||= 2;\nreturn a === 2 && b === 2 && c === 1;"
      },
      {
        "name": "||= short-circuiting behaviour",
        "exec": "let a = 1;\nlet i = 1;\na ||= ++i;\nreturn a === 1 && i === 1;"
      },
      {
        "name": "||= setter not unecessarily invoked",
        "exec": "let i = 1;\nvar obj = { get x() { return 1 }, set x(n) { i++; } };\nobj.x ||= 2;\nreturn i === 1;"
      },
      {
        "name": "&&= basic support",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_AND_assignment",
        "exec": "let a;\nlet b = 0;\nlet c = 1;\na &&= 2;\nb &&= 2;\nc &&= 2;\nreturn typeof a === 'undefined' && b === 0 && c === 2;"
      },
      {
        "name": "&&= short-circuiting behaviour",
        "exec": "let a;\nlet i = 1;\na &&= ++i;\nreturn typeof a === 'undefined' && i === 1;"
      },
      {
        "name": "&&= setter not unecessarily invoked",
        "exec": "let i = 1;\nvar obj = { get x() { return }, set x(n) { i++; } };\nobj.x &&= 2;\nreturn i === 1;"
      },
      {
        "name": "??= basic support",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_nullish_assignment",
        "exec": "let a;\nlet b = 0;\nlet c = 1;\na ??= 2;\nb ??= 2;\nc ??= 2;\nreturn a === 2 && b === 0 && c === 1;"
      },
      {
        "name": "??= short-circuiting behaviour",
        "exec": "let a = 1;\nlet i = 1;\na ??= ++i;\nreturn a === 1 && i === 1;"
      },
      {
        "name": "??= setter not unecessarily invoked",
        "exec": "let i = 1;\nvar obj = { get x() { return 1 }, set x(n) { i++; } };\nobj.x ??= 2;\nreturn i === 1;"
      }
    ]
  },
  {
    "name": "numeric separators",
    "target": "es2016",
    "category": "2021 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-numeric-separator",
    "exec": "return 1_000_000.000_001 === 1000000.000001 &&\n  0b1010_0001_1000_0101 === 0b1010000110000101;"
  },
  {
    "name": "instance class fields",
    "target": "es2016",
    "category": "2022 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-class-fields",
    "subtests": [
      {
        "name": "public instance class fields",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Class_elements#Public_instance_fields",
        "exec": "class C {\n  x = 'x';\n}\nreturn new C().x === 'x';"
      },
      {
        "name": "private instance class fields basic support",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Class_elements#Private_instance_fields",
        "exec": "class C {\n  #x;\n  constructor(x) {\n    this.#x = x;\n  }\n  x() {\n    return this.#x;\n  }\n}\nreturn new C(42).x() === 42;"
      },
      {
        "name": "private instance class fields initializers",
        "exec": "class C {\n  #x = 42;\n  x() {\n    return this.#x;\n  }\n}\nreturn new C().x() === 42;"
      },
      {
        "name": "optional private instance class fields access",
        "exec": "class C {\n  #x = 42;\n  x(o = this) {\n    return o?.#x;\n  }\n}\nreturn new C().x() === 42 && new C().x(null) === void undefined;"
      },
      {
        "name": "optional deep private instance class fields access",
        "exec": "class C {\n  #x = 42;\n  x(o = { p: this }) {\n    return o?.p.#x;\n  }\n}\nreturn new C().x() === 42 && new C().x(null) === void undefined;"
      },
      {
        "name": "computed instance class fields",
        "exec": "class C {\n  ['x'] = 42;\n}\nreturn new C().x === 42;"
      },
      {
        "name": "resolving identifier in parent scope",
        "exec": "{\n  let a = [\"hello world\"];\n  class MyClass {\n    // The parenthesis below are required to trigger https://bugs.webkit.org/show_bug.cgi?id=236843\n    c = a[(0)];\n  }\n  return new MyClass().c === a[0];\n}"
      }
    ]
  },
  {
    "name": "static class fields",
    "target": "es2016",
    "category": "2022 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-static-class-features/",
    "subtests": [
      {
        "name": "public static class fields",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Class_elements#Public_static_fields",
        "exec": "class C {\n  static x = 'x';\n}\nreturn C.x === 'x';"
      },
      {
        "name": "static class fields use [[Define]]",
        "exec": "return (class X { static name = \"name\"; }).name === 'name';"
      },
      {
        "name": "private static class fields",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Class_elements#Private_static_fields",
        "exec": "class C {\n  static #x = 42;\n  x() {\n    return C.#x;\n  }\n}\nreturn new C().x() === 42;"
      },
      {
        "name": "computed static class fields",
        "exec": "class C {\n  static ['x'] = 42;\n}\nreturn C.x === 42;"
      }
    ]
  },
  {
    "name": "private class methods",
    "target": "es2016",
    "category": "2022 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-private-methods",
    "subtests": [
      {
        "name": "private instance methods",
        "exec": "class C {\n  #x() { return 42; }\n  x() {\n    return this.#x();\n  }\n}\nreturn new C().x() === 42;"
      },
      {
        "name": "private static methods",
        "exec": "class C {\n  static #x() { return 42; }\n  x() {\n    return C.#x();\n  }\n}\nreturn new C().x() === 42;"
      },
      {
        "name": "private accessor properties",
        "exec": "var y = false;\nclass C {\n  get #x() { return 42; }\n  set #x(x) { y = x; }\n  x() {\n    this.#x = true;\n    return this.#x;\n  }\n}\nreturn new C().x() === 42 && y;"
      },
      {
        "name": "private static accessor properties",
        "exec": "var y = false;\nclass C {\n  static get #x() { return 42; }\n  static set #x(x) { y = x; }\n  x() {\n    C.#x = true;\n    return C.#x;\n  }\n}\nreturn new C().x() === 42 && y;"
      }
    ]
  },
  {
    "name": "Ergonomic brand checks for private fields",
    "target": "es2016",
    "category": "2022 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-private-fields-in-in",
    "exec": "class A {\n  #x;\n  static check(obj) {\n    return #x in obj;\n  }\n}\nreturn A.check(new A) && !A.check({});"
  },
  {
    "name": ".at() method on the built-in indexables",
    "target": "es2016",
    "category": "2022 features",
    "significance": "tiny",
    "spec": "https://github.com/tc39/proposal-relative-indexing-method/",
    "subtests": [
      {
        "name": "Array.prototype.at()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/at",
        "exec": "var arr = [1, 2, 3];\nreturn arr.at(0) === 1\n  && arr.at(-3) === 1\n  && arr.at(1) === 2\n  && arr.at(-2) === 2\n  && arr.at(2) === 3\n  && arr.at(-1) === 3\n  && arr.at(3) === undefined\n  && arr.at(-4) === undefined;"
      },
      {
        "name": "String.prototype.at()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/at",
        "exec": "var str = 'abc';\nreturn str.at(0) === 'a'\n  && str.at(-3) === 'a'\n  && str.at(1) === 'b'\n  && str.at(-2) === 'b'\n  && str.at(2) === 'c'\n  && str.at(-1) === 'c'\n  && str.at(3) === undefined\n  && str.at(-4) === undefined;"
      },
      {
        "name": "%TypedArray%.prototype.at()",
        "exec": "return [\n  'Int8Array',\n  'Uint8Array',\n  'Uint8ClampedArray',\n  'Int16Array',\n  'Uint16Array',\n  'Int32Array',\n  'Uint32Array',\n  'Float32Array',\n  'Float64Array'\n].every(function (TypedArray) {\n  var Constructor = globalThis[TypedArray];\n  if (typeof Constructor !== 'function') {\n    return false;\n  }\n  var arr = new Constructor([1, 2, 3]);\n  return arr.at(0) === 1\n    && arr.at(-3) === 1\n    && arr.at(1) === 2\n    && arr.at(-2) === 2\n    && arr.at(2) === 3\n    && arr.at(-1) === 3\n    && arr.at(3) === undefined\n    && arr.at(-4) === undefined;\n});"
      }
    ]
  },
  {
    "name": "Object.hasOwn",
    "target": "es2016",
    "category": "2022 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-accessible-object-hasownproperty",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwn",
    "subtests": [
      {
        "name": "Basic functionality",
        "exec": "return Object.hasOwn({ x: 2 }, \"x\") === true;"
      },
      {
        "name": "ToObject called before ToPropertyKey",
        "exec": "var ok = !!Object.hasOwn;\ntry {\n  Object.hasOwn(null, { toString: function () { ok = false } });\n  return false;\n} catch (e) {\n  return ok;\n}"
      }
    ]
  },
  {
    "name": "Class static initialization blocks",
    "target": "es2016",
    "category": "2022 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-class-static-block",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Static_initialization_blocks",
    "exec": "let ok = false;\nclass A {\n  static { ok = true; }\n}\nreturn ok;"
  },
  {
    "name": "Error.cause property",
    "target": "es2016",
    "category": "2022 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-error-cause",
    "subtests": [
      {
        "name": "Error has cause",
        "exec": "var error = new Error('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "Error.prototype lacks cause",
        "exec": "return !('cause' in Error.prototype);"
      },
      {
        "name": "EvalError has cause",
        "exec": "var error = new EvalError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "EvalError.prototype lacks cause",
        "exec": "return !('cause' in EvalError.prototype);"
      },
      {
        "name": "RangeError has cause",
        "exec": "var error = new RangeError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "RangeError.prototype lacks cause",
        "exec": "return !('cause' in RangeError.prototype);"
      },
      {
        "name": "ReferenceError has cause",
        "exec": "var error = new ReferenceError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "ReferenceError.prototype lacks cause",
        "exec": "return !('cause' in ReferenceError.prototype);"
      },
      {
        "name": "SyntaxError has cause",
        "exec": "var error = new SyntaxError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "SyntaxError.prototype lacks cause",
        "exec": "return !('cause' in SyntaxError.prototype);"
      },
      {
        "name": "TypeError has cause",
        "exec": "var error = new TypeError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "TypeError.prototype lacks cause",
        "exec": "return !('cause' in TypeError.prototype);"
      },
      {
        "name": "URIError has cause",
        "exec": "var error = new URIError('error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "URIError.prototype lacks cause",
        "exec": "return !('cause' in URIError.prototype);"
      },
      {
        "name": "AggregateError has cause",
        "exec": "var error = new AggregateError([], 'error', { cause: 'cause' })\nreturn error.hasOwnProperty('cause') && error.cause === 'cause';"
      },
      {
        "name": "AggregateError.prototype lacks cause",
        "exec": "return !('cause' in AggregateError.prototype);"
      }
    ]
  },
  {
    "name": "RegExp Match Indices (`hasIndices` / `d` flag)",
    "target": "es2016",
    "category": "2022 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-match-indices",
    "subtests": [
      {
        "name": "constructor supports it",
        "exec": "return new RegExp('a', 'd') instanceof RegExp;"
      },
      {
        "name": "shows up in flags",
        "exec": "var expected = ['hasIndices'];\n// Sorted alphabetically by shortname – \"dgimsuy\".\nif ('global' in RegExp.prototype) expected.push('global');\nif ('ignoreCase' in RegExp.prototype) expected.push('ignoreCase');\nif ('multiline' in RegExp.prototype) expected.push('multiline');\nif ('dotAll' in RegExp.prototype) expected.push('dotAll');\nif ('unicode' in RegExp.prototype) expected.push('unicode');\nif ('sticky' in RegExp.prototype) expected.push('sticky');\nvar actual = [];\nvar p = new Proxy({}, { get: function (o, k) { actual.push(k); return o[k]; }});\nObject.getOwnPropertyDescriptor(RegExp.prototype, 'flags').get.call(p);\nif (expected.length !== actual.length) return false;\nfor (var i = 0; i < expected.length; i++) {\n  if (expected[i] !== actual[i]) return false;\n}\nreturn true;"
      }
    ]
  },
  {
    "name": "Array find from last",
    "target": "es2016",
    "category": "2023 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-array-find-from-last",
    "subtests": [
      {
        "name": "Array.prototype.findLast",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLast",
        "exec": "var arr = [{ x: 1 }, { x: 2 }, { x: 1 }, { x: 2 }];\nreturn arr.findLast(function (o) { return o.x === 1; }) === arr[2];"
      },
      {
        "name": "Array.prototype.findLastIndex",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findLastIndex",
        "exec": "var arr = [{ x: 1 }, { x: 2 }, { x: 1 }, { x: 2 }];\nreturn arr.findLastIndex(function (o) { return o.x === 1; }) === 2;"
      }
    ]
  },
  {
    "name": "Hashbang Grammar",
    "target": "es2016",
    "category": "2023 features",
    "significance": "tiny",
    "spec": "https://github.com/tc39/proposal-hashbang/",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Hashbang_comments",
    "exec": "try {\n  return !eval('#!/wash/your/hands');\n} catch (e) {\n  return false\n}"
  },
  {
    "name": "Change Array by copy",
    "target": "es2016",
    "category": "2023 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-change-array-by-copy",
    "subtests": [
      {
        "name": "Array.prototype.toReversed()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toReversed",
        "exec": "var arr = [1, 2, 3];\nreturn arr.toReversed()[0] === 3 && arr[0] === 1;"
      },
      {
        "name": "Array.prototype.toSorted()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSorted",
        "exec": "var arr = ['C', 'A', 'B'];\nreturn arr.toSorted()[0] === 'A' && arr[0] === 'C';"
      },
      {
        "name": "Array.prototype.toSpliced()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toSpliced",
        "exec": "var arr = ['A', 'C'];\nreturn arr.toSpliced(1, 0, 'B')[1] === 'B' && arr[1] === 'C';"
      },
      {
        "name": "Array.prototype.with()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/with",
        "exec": "var arr = ['A', 'X', 'C'];\nreturn arr.with(1, 'B')[1] === 'B' && arr[1] === 'X';"
      },
      {
        "name": "TypedArray.prototype.toReversed()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/toReversed",
        "exec": "var arr = new Uint8Array([1, 2, 3]);\nreturn arr.toReversed()[0] == 3 && arr[0] == 1;"
      },
      {
        "name": "TypedArray.prototype.toSorted()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/toSorted",
        "exec": "var arr = new Uint8Array([3, 1, 2]);\nreturn arr.toSorted()[0] == 1 && arr[0] == 3;"
      },
      {
        "name": "TypedArray.prototype.with()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/with",
        "exec": "var arr = new Uint8Array([1, 0, 2]);\nreturn arr.with(1, 2)[1] == 2 && arr[1] == 0;"
      }
    ]
  },
  {
    "name": "RegExp `v` flag",
    "target": "es2016",
    "category": "2024 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-v-flag",
    "subtests": [
      {
        "name": "set notations",
        "exec": "return /[\\p{ASCII}&&\\p{Decimal_Number}]/v.test(\"0\")\n&& /[\\p{Any}--[\\x01-\\u{10ffff}]]/v.test(\"\\0\")"
      },
      {
        "name": "properties of Strings",
        "exec": "return /^\\p{Emoji_Keycap_Sequence}$/v.test(\"*\\uFE0F\\u20E3\")\n&& !/^\\p{Emoji_Keycap_Sequence}$/v.test(\"*\");"
      },
      {
        "name": "constructor supports it",
        "exec": "return new RegExp('a', 'v') instanceof RegExp;"
      },
      {
        "name": "shows up in flags",
        "exec": "var flags = [];\nvar p = new Proxy({}, { get: function (o, k) { flags.push(k); return o[k]; }});\nObject.getOwnPropertyDescriptor(RegExp.prototype, 'flags').get.call(p);\nreturn flags.indexOf(\"unicodeSets\") !== -1;"
      },
      {
        "name": "Unicode 15.1",
        "exec": "return /^\\p{RGI_Emoji}$/v.test(\"🐦‍🔥\");"
      },
      {
        "name": "Unicode 16.0",
        "exec": "return /^\\p{RGI_Emoji}$/v.test(\"🇨🇶\");"
      }
    ]
  },
  {
    "name": "ArrayBuffer.prototype.transfer",
    "target": "es2016",
    "category": "2024 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-arraybuffer-transfer",
    "subtests": [
      {
        "name": "ArrayBuffer.prototype.transfer()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/transfer",
        "exec": "const buffer1 = new Uint8Array([1, 2]).buffer;\nconst buffer2 = buffer1.transfer();\nreturn buffer1.byteLength === 0\n  && buffer2.byteLength === 2;"
      },
      {
        "name": "ArrayBuffer.prototype.transferToFixedLength()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/transferToFixedLength",
        "exec": "const buffer1 = new Uint8Array([1, 2]).buffer;\nconst buffer2 = buffer1.transferToFixedLength();\nreturn buffer1.byteLength === 0\n  && buffer2.byteLength === 2;"
      },
      {
        "name": "ArrayBuffer.prototype.detached",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/detached",
        "exec": "const buffer1 = new Uint8Array([1, 2]).buffer;\nconst buffer2 = buffer1.transfer();\nreturn buffer1.detached && !buffer2.detached;"
      }
    ]
  },
  {
    "name": "Promise.withResolvers",
    "target": "es2016",
    "category": "2024 features",
    "significance": "tiny",
    "spec": "https://tc39.es/proposal-promise-with-resolvers/",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers",
    "exec": "var obj = Promise.withResolvers();\nreturn obj instanceof Object\n  && obj.promise instanceof Promise\n  && typeof obj.resolve === 'function'\n  && typeof obj.reject === 'function';"
  },
  {
    "name": "Array Grouping",
    "target": "es2016",
    "category": "2024 features",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-array-grouping",
    "subtests": [
      {
        "name": "Object.groupBy()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/groupBy",
        "exec": "const array = [1, 2, 3, 4];\nconst obj = Object.groupBy(array, (num, index) => {\n  return num % 2 === 0 ? 'even': 'odd';\n});\nreturn !('toString' in obj) && obj.even[0] == 2 && obj.odd[0] == 1;"
      },
      {
        "name": "Map.groupBy()",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/groupBy",
        "exec": "const array = [1, 2, 3, 4];\nconst odd  = { odd: true };\nconst even = { even: true };\nconst map = Map.groupBy(array, (num, index) => {\n  return num % 2 === 0 ? even: odd;\n});\nreturn map instanceof Map && map.get(even)[0] === 2 && map.get(odd)[0] === 1;"
      }
    ]
  },
  {
    "name": "Duplicate named capturing groups",
    "target": "es2016",
    "category": "2025 features",
    "significance": "tiny",
    "spec": "https://github.com/tc39/proposal-duplicate-named-capturing-groups",
    "exec": "return /(?<year>[0-9]{4})-[0-9]{2}|[0-9]{2}-(?<year>[0-9]{4})/.test(\"12-1995\");"
  },
  {
    "name": "Set methods",
    "target": "es2016",
    "category": "2025 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-set-methods",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set#instance_methods",
    "subtests": [
      {
        "name": "Set.prototype.intersection()",
        "exec": "var set = new Set([1, 2, 3]).intersection(new Set([2, 3, 4]));\nreturn set.size === 2\n  && set.has(2)\n  && set.has(3);"
      },
      {
        "name": "Set.prototype.union()",
        "exec": "var set = new Set([1, 2]).union(new Set([2, 3]));\nreturn set.size === 3\n  && set.has(1)\n  && set.has(2)\n  && set.has(3);"
      },
      {
        "name": "Set.prototype.difference()",
        "exec": "var set = new Set([1, 2, 3]).difference(new Set([3, 4]));\nreturn set.size === 2\n  && set.has(1)\n  && set.has(2);"
      },
      {
        "name": "Set.prototype.symmetricDifference()",
        "exec": "var set = new Set([1, 2]).symmetricDifference(new Set([2, 3]));\nreturn set.size === 2\n  && set.has(1)\n  && set.has(3);"
      },
      {
        "name": "Set.prototype.isDisjointFrom()",
        "exec": "return new Set([1, 2, 3]).isDisjointFrom(new Set([4, 5, 6]));"
      },
      {
        "name": "Set.prototype.isSubsetOf()",
        "exec": "return new Set([1, 2, 3]).isSubsetOf(new Set([5, 4, 3, 2, 1]));"
      },
      {
        "name": "Set.prototype.isSupersetOf()",
        "exec": "return new Set([5, 4, 3, 2, 1]).isSupersetOf(new Set([1, 2, 3]));"
      }
    ]
  },
  {
    "name": "RegExp Pattern Modifiers",
    "target": "es2016",
    "category": "2025 features",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-regexp-modifiers",
    "subtests": [
      {
        "name": "i flag",
        "exec": "const regex = /^[a-z](?-i:[a-z])$/i;\nreturn regex.test(\"ab\") && regex.test(\"Ab\") && !regex.test(\"aB\");"
      },
      {
        "name": "m flag",
        "exec": "const regex = /^a|(?m:^b)/;\nreturn regex.test(\"a\") && regex.test(\"b\") && regex.test(\"c\\nb\") && !regex.test(\"c\\na\");"
      },
      {
        "name": "s flag",
        "exec": "const regex = /.(?-s:.)/s;\nreturn regex.test(\"\\na\") && regex.test(\"aa\") && !regex.test(\"\\n\\n\");"
      }
    ]
  },
  {
    "name": "Iterator Helpers",
    "target": "es2016",
    "category": "2025 features",
    "significance": "large",
    "spec": "https://github.com/tc39/proposal-iterator-helpers",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator#iterator_helpers",
    "subtests": [
      {
        "name": "instanceof Iterator",
        "exec": "return [1, 2, 3].values() instanceof Iterator;"
      },
      {
        "name": "extends Iterator",
        "exec": "class Class extends Iterator { }\nconst instance = new Class();\nreturn instance[Symbol.iterator]() === instance;"
      },
      {
        "name": "Iterator.from, iterable",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/from",
        "exec": "const iterator = Iterator.from([1, 2, 3]);\nreturn 'next' in iterator\n  && iterator instanceof Iterator\n  && Array.from(iterator).join() === '1,2,3';"
      },
      {
        "name": "Iterator.from, iterator",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/from",
        "exec": "const iterator = Iterator.from({\n  i: 0,\n  next() {\n    return { value: ++this.i, done: this.i > 3 };\n  }\n});\nreturn 'next' in iterator\n  && iterator instanceof Iterator\n  && Array.from(iterator).join() === '1,2,3';"
      },
      {
        "name": "Iterator.prototype.drop",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/drop",
        "exec": "return Array.from([1, 2, 3].values().drop(1)).join() === '2,3';"
      },
      {
        "name": "Iterator.prototype.every",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/every",
        "exec": "return [1, 2, 3].values().every(it => typeof it === 'number');"
      },
      {
        "name": "Iterator.prototype.filter",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/filter",
        "exec": "return Array.from([1, 2, 3].values().filter(it => it % 2)).join() === '1,3';"
      },
      {
        "name": "Iterator.prototype.find",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/find",
        "exec": "return [1, 2, 3].values().find(it => it % 2) === 1;"
      },
      {
        "name": "Iterator.prototype.flatMap",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/flatMap",
        "exec": "return Array.from([1, 2, 3].values().flatMap(it => [it, 0])).join() === '1,0,2,0,3,0';"
      },
      {
        "name": "Iterator.prototype.forEach",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/forEach",
        "exec": "let result = '';\n[1, 2, 3].values().forEach(it => result += it);\nreturn result === '123';"
      },
      {
        "name": "Iterator.prototype.map",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/map",
        "exec": "return Array.from([1, 2, 3].values().map(it => it * it)).join() === '1,4,9';"
      },
      {
        "name": "Iterator.prototype.reduce",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/reduce",
        "exec": "return [1, 2, 3].values().reduce((a, b) => a + b) === 6;"
      },
      {
        "name": "Iterator.prototype.some",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/some",
        "exec": "return [1, 2, 3].values().some(it => typeof it === 'number');"
      },
      {
        "name": "Iterator.prototype.take",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/take",
        "exec": "return Array.from([1, 2, 3].values().take(2)).join() === '1,2';"
      },
      {
        "name": "Iterator.prototype.toArray",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/toArray",
        "exec": "const array = [1, 2, 3].values().toArray();\nreturn Array.isArray(array) && array.join() === '1,2,3';"
      },
      {
        "name": "Iterator.prototype[@@toStringTag]",
        "exec": "return Iterator.prototype[Symbol.toStringTag] === 'Iterator';"
      }
    ]
  },
  {
    "name": "Promise.try",
    "target": "es2016",
    "category": "2025 features",
    "significance": "tiny",
    "spec": "https://github.com/tc39/proposal-promise-try",
    "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/try",
    "exec": "var called = false;\nvar argsMatch = false;\nvar p = Promise.try(function () { called = true; })\nvar p2 = Promise.try(function () {\n  'use strict';\n  argsMatch = this === undefined && arguments.length === 2 && args[0] === p && args[1] === 2;\n}, [p, 2]);\n\nreturn p instanceof Promise && called && argsMatch;"
  },
  {
    "name": "Class and Property Decorators",
    "target": "esnext",
    "category": "Stage 3",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-decorators",
    "subtests": [
      {
        "name": "class decorators",
        "spec": "https://github.com/wycats/javascript-decorators",
        "exec": "class A {\n  @nonconf\n  get B() {}\n}\nfunction nonconf(target, name, descriptor) {\n  descriptor.configurable = false;\n  return descriptor;\n}\nreturn Object.getOwnPropertyDescriptor(A.prototype, \"B\").configurable === false;"
      }
    ]
  },
  {
    "name": "Legacy RegExp features in JavaScript",
    "target": "esnext",
    "category": "Stage 3",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-regexp-legacy-features",
    "subtests": [
      {
        "name": "RegExp \"lastMatch\"",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastMatch",
        "exec": "function () {\nvar re = /\\w/;\nre.exec('x');\nreturn RegExp.lastMatch === 'x';\n      }"
      },
      {
        "name": "RegExp.$1-$9",
        "mdn": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/n",
        "exec": "function () {\nfor (var i = 1; i < 10; i++) {\n  if (!(('$' + i) in RegExp)) return false;\n}\nreturn true;\n      }"
      }
    ]
  },
  {
    "name": "RegExp Escaping",
    "target": "esnext",
    "category": "Stage 3",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-regex-escaping",
    "exec": "return RegExp.escape(\"The Quick Brown Fox\") === \"The\\\\ Quick\\\\ Brown\\\\ Fox\" &&\n  RegExp.escape(\"(*.*)\") === \"\\\\(\\\\*\\\\.\\\\*\\\\)\" &&\n  RegExp.escape(\"｡^･ｪ･^｡\") === \"｡\\\\^･ｪ･\\\\^｡\" &&\n  RegExp.escape(\"\\\\d \\\\D (?:)\") === \"\\\\\\\\d \\\\\\\\D \\\\(\\\\?\\\\:\\\\)\";"
  },
  {
    "name": "Uint8Array to/from base64 and hex",
    "target": "esnext",
    "category": "Stage 3",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-arraybuffer-base64",
    "subtests": [
      {
        "name": "Uint8Array.toBase64()",
        "exec": "const arr = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nreturn arr.toBase64() === \"SGVsbG8gV29ybGQ=\";"
      },
      {
        "name": "Uint8Array.fromBase64()",
        "exec": "const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nconst arr2 = Uint8Array.fromBase64(\"SGVsbG8gV29ybGQ=\");\nreturn arr1.length === arr2.length &&\n       arr1.every((element, index) => element === arr2[index]);"
      },
      {
        "name": "Uint8Array.setFromBase64()",
        "exec": "const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nlet arr2 = new Uint8Array(16);\nlet { read, written } = arr2.setFromBase64(\"SGVsbG8gV29ybGQ=\");\nreturn read == 16 && written == 11 &&\n       arr1.every((element, index) => element === arr2[index]);"
      },
      {
        "name": "Uint8Array.toHex()",
        "exec": "const arr = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nreturn arr.toHex() === \"48656c6c6f20576f726c64\";"
      },
      {
        "name": "Uint8Array.fromHex()",
        "exec": "const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nconst arr2 = Uint8Array.fromHex(\"48656c6c6f20576f726c64\");\nreturn arr1.length === arr2.length &&\n       arr1.every((element, index) => element === arr2[index]);"
      },
      {
        "name": "Uint8Array.setFromHex()",
        "exec": "const arr1 = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);\nlet arr2 = new Uint8Array(16);\nlet { read, written } = arr2.setFromHex(\"48656c6c6f20576f726c64\");\nreturn read == 22 && written == 11 &&\n       arr1.every((element, index) => element === arr2[index]);"
      }
    ]
  },
  {
    "name": "ShadowRealm",
    "target": "esnext",
    "category": "Stage 2.7",
    "significance": "large",
    "spec": "https://github.com/tc39/proposal-shadowrealm",
    "exec": "return typeof ShadowRealm === \"function\"\n  && [\"evaluate\", \"importValue\"].every(function(key){\n    return key in ShadowRealm.prototype;\n  });"
  },
  {
    "name": "Generator function.sent Meta Property",
    "target": "esnext",
    "category": "Stage 2",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-function.sent",
    "exec": "var result;\nfunction* generator() {\n  result = function.sent;\n}\nvar iter = generator();\niter.next('tromple');\nreturn result === 'tromple';"
  },
  {
    "name": "throw expressions",
    "target": "esnext",
    "category": "Stage 2",
    "significance": "medium",
    "spec": "https://github.com/tc39/proposal-throw-expressions",
    "subtests": [
      {
        "name": "logical",
        "exec": "var a, b;\ntry {\n  a = 19 || throw 77;\n  b = 88 && throw 23;\n} catch (e) {\n  return a + e === 42;\n}"
      },
      {
        "name": "parameter initializers",
        "exec": "function fn (arg = throw 42) {\n  return arg;\n}\n\nif (fn(21) !== 21) return false;\n\ntry {\n  fn();\n} catch (e) {\n  return e === 42;\n}"
      },
      {
        "name": "arrow function bodies",
        "exec": "var fn = () => throw 42;\ntry {\n  fn();\n} catch (e) {\n  return e === 42;\n}"
      },
      {
        "name": "conditionals",
        "exec": "true ? 42 : throw 21;\ntry {\n  false ? 42 : throw 21;\n} catch (e) {\n  return e === 21;\n}"
      }
    ]
  },
  {
    "name": "Map.prototype.upsert",
    "target": "esnext",
    "category": "Stage 2",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-upsert",
    "subtests": [
      {
        "name": "Map.prototype.upsert",
        "exec": "const map = new Map([['a', 1]]);\nif (map.upsert('a', it => 2, () => 3) !== 2) return false;\nif (map.upsert('b', it => 2, () => 3) !== 3) return false;\nreturn Array.from(map).join() === 'a,2,b,3';"
      },
      {
        "name": "WeakMap.prototype.upsert",
        "exec": "const a = {}, b = {};\nconst map = new WeakMap([[a, 1]]);\nif (map.upsert(a, it => 2, () => 3) !== 2) return false;\nif (map.upsert(b, it => 2, () => 3) !== 3) return false;\nreturn map.get(a) === 2 && map.get(b) === 3;"
      }
    ]
  },
  {
    "name": "Array.isTemplateObject",
    "target": "esnext",
    "category": "Stage 2",
    "significance": "small",
    "spec": "https://github.com/tc39/proposal-array-is-template-object",
    "exec": "return !Array.isTemplateObject([])\n  && Array.isTemplateObject((it => it)`a${1}c`);"
  },
  {
    "name": "Async Iterator Helpers",
    "target": "esnext",
    "category": "Stage 2",
    "significance": "large",
    "spec": "https://github.com/tc39/proposal-async-iterator-helpers",
    "subtests": [
      {
        "name": "instanceof AsyncIterator",
        "exec": "return (async function*() {})() instanceof AsyncIterator;"
      },
      {
        "name": "extends AsyncIterator",
        "exec": "class Class extends AsyncIterator { }\nconst instance = new Class();\nreturn instance[Symbol.asyncIterator]() === instance;"
      },
      {
        "name": "AsyncIterator.from, async iterable",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\nconst iterator = AsyncIterator.from(async function*() { yield * [1, 2, 3] }());\n\nif (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false;\n\ntoArray(iterator).then(it => {\n  if (it.join() === '1,2,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.from, iterable",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\nconst iterator = AsyncIterator.from([1, 2, 3]);\n\nif (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false;\n\ntoArray(iterator).then(it => {\n  if (it.join() === '1,2,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.from, iterator",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\nconst iterator = AsyncIterator.from([1, 2, 3].values());\n\nif (!('next' in iterator) || !(iterator instanceof AsyncIterator)) return false;\n\ntoArray(iterator).then(it => {\n  if (it.join() === '1,2,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.drop",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\ntoArray(async function*() { yield * [1, 2, 3] }().drop(1)).then(it => {\n  if (it.join() === '2,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.every",
        "exec": "(async function*() { yield * [1, 2, 3] })().every(it => typeof it === 'number').then(it => {\n  if (it === true) asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.filter",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\ntoArray(async function*() { yield * [1, 2, 3] }().filter(it => it % 2)).then(it => {\n  if (it.join() === '1,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.find",
        "exec": "(async function*() { yield * [1, 2, 3] })().find(it => it % 2).then(it => {\n  if (it === 1) asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.flatMap",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\ntoArray(async function*() { yield * [1, 2, 3] }().flatMap(it => [it, 0])).then(it => {\n  if (it.join() === '1,0,2,0,3,0') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.forEach",
        "exec": "let result = '';\n(async function*() { yield * [1, 2, 3] })().forEach(it => result += it).then(() => {\n  if (result === '123') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.map",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\ntoArray(async function*() { yield * [1, 2, 3] }().map(it => it * it)).then(it => {\n  if (it.join() === '1,4,9') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.reduce",
        "exec": "(async function*() { yield * [1, 2, 3] })().reduce((a, b) => a + b).then(it => {\n  if (it === 6) asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.some",
        "exec": "(async function*() { yield * [1, 2, 3] })().some(it => typeof it === 'number').then(it => {\n  if (it === true) asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.take",
        "exec": "async function toArray(iterator) {\n  const result = [];\n  for await (const it of iterator) result.push(it);\n  return result;\n}\n\ntoArray(async function*() { yield * [1, 2, 3] }().take(2)).then(it => {\n  if (it.join() === '1,2') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype.toArray",
        "exec": "(async function*() { yield * [1, 2, 3] })().toArray().then(it => {\n  if (Array.isArray(it) && it.join() === '1,2,3') asyncTestPassed();\n});"
      },
      {
        "name": "AsyncIterator.prototype[@@toStringTag]",
        "exec": "return AsyncIterator.prototype[Symbol.toStringTag] === 'AsyncIterator';"
      }
    ]
  }
]