provide isError and use it in place of instanceof Error

Fixes #15868

src/.eslintrc.json

@@ -50,6 +50,7 @@
     "isNumber": false,
     "isNumberNaN": false,
     "isDate": false,
+    "isError": false,
     "isArray": false,
     "isFunction": false,
     "isRegExp": false,

src/Angular.js

@@ -45,6 +45,7 @@
   isNumber,
   isNumberNaN,
   isDate,
+  isError,
   isArray,
   isFunction,
   isRegExp,
@@ -673,6 +674,28 @@ function isDate(value) {
  */
 var isArray = Array.isArray;
 
+/**
+ * @ngdoc function
+ * @name angular.isError
+ * @module ng
+ * @kind function
+ *
+ * @description
+ * Determines if a reference is an `Error`.
+ *
+ * @param {*} value Reference to check.
+ * @returns {boolean} True if `value` is an `Error`.
+ */
+function isError(value) {
+  var tag = ({}).toString.call(value);
+  switch (tag) {
+    case '[object Error]': return true;
+    case '[object Exception]': return true;
+    case '[object DOMException]': return true;
+    default: return value instanceof Error;
+  }
+}
+
 /**
  * @ngdoc function
  * @name angular.isFunction

src/ng/compile.js

@@ -3098,7 +3098,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           }
           linkQueue = null;
         }).catch(function(error) {
-          if (error instanceof Error) {
+          if (isError(error)) {
             $exceptionHandler(error);
           }
         });

src/ng/log.js

@@ -132,7 +132,7 @@ function $LogProvider() {
     };
 
     function formatError(arg) {
-      if (arg instanceof Error) {
+      if (isError(arg)) {
         if (arg.stack && formatStackTrace) {
           arg = (arg.message && arg.stack.indexOf(arg.message) === -1)
               ? 'Error: ' + arg.message + '\n' + arg.stack

src/ng/q.js

@@ -381,7 +381,7 @@ function qFactory(nextTick, exceptionHandler, errorOnUnhandledRejections) {
       if (!toCheck.pur) {
         toCheck.pur = true;
         var errorMessage = 'Possibly unhandled rejection: ' + toDebugString(toCheck.value);
-        if (toCheck.value instanceof Error) {
+        if (isError(toCheck.value)) {
           exceptionHandler(toCheck.value, errorMessage);
         } else {
           exceptionHandler(errorMessage);

src/ngMock/angular-mocks.js

@@ -984,7 +984,7 @@ angular.mock.dump = function(object) {
     } else if (angular.isObject(object)) {
       if (angular.isFunction(object.$eval) && angular.isFunction(object.$apply)) {
         out = serializeScope(object);
-      } else if (object instanceof Error) {
+      } else if (angular.isError(object)) {
         out = object.stack || ('' + object.name + ': ' + object.message);
       } else {
         // TODO(i): this prevents methods being logged,

test/.eslintrc.json

@@ -64,6 +64,7 @@
     "isNumber": false,
     "isNumberNaN": false,
     "isDate": false,
+    "isError": false,
     "isArray": false,
     "isFunction": false,
     "isRegExp": false,

test/minErrSpec.js

@@ -17,6 +17,7 @@ describe('minErr', function() {
   it('should return an Error factory', function() {
     var myError = testError('test', 'Oops');
     expect(myError instanceof Error).toBe(true);
+    expect(isError(myError)).toBe(true);
   });
 
   it('should generate stack trace at the frame where the minErr instance was called', function() {

test/ng/qSpec.js

@@ -37,7 +37,7 @@ describe('q', function() {
   // The following private functions are used to help with logging for testing invocation of the
   // promise callbacks.
   function _argToString(arg) {
-    return (typeof arg === 'object' && !(arg instanceof Error)) ? toJson(arg) : '' + arg;
+    return (typeof arg === 'object' && !(isError(arg))) ? toJson(arg) : '' + arg;
   }
 
   function _argumentsToString(args) {