encapsulate some more built-ins, reuse array-unique-by in reflect.get-metadata-keys

Author: zloirock

packages/core-js/internals/array-unique-by.js

@@ -6,6 +6,11 @@ var lengthOfArrayLike = require('../internals/length-of-array-like');
 var toObject = require('../internals/to-object');
 var arraySpeciesCreate = require('../internals/array-species-create');
 
+var Map = getBuiltIn('Map');
+var MapPrototype = Map.prototype;
+var mapForEach = uncurryThis(MapPrototype.forEach);
+var mapHas = uncurryThis(MapPrototype.has);
+var mapSet = uncurryThis(MapPrototype.set);
 var push = uncurryThis([].push);
 
 // `Array.prototype.uniqueBy` method
@@ -14,7 +19,6 @@ module.exports = function uniqueBy(resolver) {
   var that = toObject(this);
   var length = lengthOfArrayLike(that);
   var result = arraySpeciesCreate(that, 0);
-  var Map = getBuiltIn('Map');
   var map = new Map();
   var resolverFunction, index, item, key;
   if (resolver != null) resolverFunction = aCallable(resolver);
@@ -24,9 +28,9 @@ module.exports = function uniqueBy(resolver) {
   for (index = 0; index < length; index++) {
     item = that[index];
     key = resolverFunction(item);
-    if (!map.has(key)) map.set(key, item);
+    if (!mapHas(map, key)) mapSet(map, key, item);
   }
-  map.forEach(function (value) {
+  mapForEach(map, function (value) {
     push(result, value);
   });
   return result;

packages/core-js/internals/reflect-metadata.js

@@ -2,10 +2,13 @@
 require('../modules/es.map');
 require('../modules/es.weak-map');
 var getBuiltIn = require('../internals/get-built-in');
+var uncurryThis = require('../internals/function-uncurry-this');
 var shared = require('../internals/shared');
 
 var Map = getBuiltIn('Map');
 var WeakMap = getBuiltIn('WeakMap');
+var push = uncurryThis([].push);
+
 var metadata = shared('metadata');
 var store = metadata.store || (metadata.store = new WeakMap());
 
@@ -39,7 +42,7 @@ var ordinaryDefineOwnMetadata = function (MetadataKey, MetadataValue, O, P) {
 var ordinaryOwnMetadataKeys = function (target, targetKey) {
   var metadataMap = getOrCreateMetadataMap(target, targetKey, false);
   var keys = [];
-  if (metadataMap) metadataMap.forEach(function (_, key) { keys.push(key); });
+  if (metadataMap) metadataMap.forEach(function (_, key) { push(keys, key); });
   return keys;
 };
 

packages/core-js/modules/esnext.reflect.get-metadata-keys.js

@@ -1,28 +1,21 @@
-// TODO: in core-js@4, move /modules/ dependencies to public entries for better optimization by tools like `preset-env`
-require('../modules/es.set');
 var $ = require('../internals/export');
-var getBuiltIn = require('../internals/get-built-in');
+var uncurryThis = require('../internals/function-uncurry-this');
 var ReflectMetadataModule = require('../internals/reflect-metadata');
 var anObject = require('../internals/an-object');
 var getPrototypeOf = require('../internals/object-get-prototype-of');
-var iterate = require('../internals/iterate');
+var $arrayUniqueBy = require('../internals/array-unique-by');
 
-var Set = getBuiltIn('Set');
+var arrayUniqueBy = uncurryThis($arrayUniqueBy);
+var concat = uncurryThis([].concat);
 var ordinaryOwnMetadataKeys = ReflectMetadataModule.keys;
 var toMetadataKey = ReflectMetadataModule.toKey;
 
-var from = function (iter) {
-  var result = [];
-  iterate(iter, result.push, { that: result });
-  return result;
-};
-
 var ordinaryMetadataKeys = function (O, P) {
   var oKeys = ordinaryOwnMetadataKeys(O, P);
   var parent = getPrototypeOf(O);
   if (parent === null) return oKeys;
   var pKeys = ordinaryMetadataKeys(parent, P);
-  return pKeys.length ? oKeys.length ? from(new Set(oKeys.concat(pKeys))) : pKeys : oKeys;
+  return pKeys.length ? oKeys.length ? arrayUniqueBy(concat(oKeys, pKeys)) : pKeys : oKeys;
 };
 
 // `Reflect.getMetadataKeys` method