--- /dev/null
+'use strict';
+var DESCRIPTORS = require('../internals/descriptors');
+var fails = require('../internals/fails');
+var objectKeys = require('../internals/object-keys');
+var getOwnPropertySymbolsModule = require('../internals/object-get-own-property-symbols');
+var propertyIsEnumerableModule = require('../internals/object-property-is-enumerable');
+var toObject = require('../internals/to-object');
+var IndexedObject = require('../internals/indexed-object');
+
+var nativeAssign = Object.assign;
+var defineProperty = Object.defineProperty;
+
+// `Object.assign` method
+// https://tc39.es/ecma262/#sec-object.assign
+module.exports = !nativeAssign || fails(function () {
+ // should have correct order of operations (Edge bug)
+ if (DESCRIPTORS && nativeAssign({ b: 1 }, nativeAssign(defineProperty({}, 'a', {
+ enumerable: true,
+ get: function () {
+ defineProperty(this, 'b', {
+ value: 3,
+ enumerable: false
+ });
+ }
+ }), { b: 2 })).b !== 1) return true;
+ // should work with symbols and should have deterministic property order (V8 bug)
+ var A = {};
+ var B = {};
+ /* global Symbol -- required for testing */
+ var symbol = Symbol();
+ var alphabet = 'abcdefghijklmnopqrst';
+ A[symbol] = 7;
+ alphabet.split('').forEach(function (chr) { B[chr] = chr; });
+ return nativeAssign({}, A)[symbol] != 7 || objectKeys(nativeAssign({}, B)).join('') != alphabet;
+}) ? function assign(target, source) { // eslint-disable-line no-unused-vars -- required for `.length`
+ var T = toObject(target);
+ var argumentsLength = arguments.length;
+ var index = 1;
+ var getOwnPropertySymbols = getOwnPropertySymbolsModule.f;
+ var propertyIsEnumerable = propertyIsEnumerableModule.f;
+ while (argumentsLength > index) {
+ var S = IndexedObject(arguments[index++]);
+ var keys = getOwnPropertySymbols ? objectKeys(S).concat(getOwnPropertySymbols(S)) : objectKeys(S);
+ var length = keys.length;
+ var j = 0;
+ var key;
+ while (length > j) {
+ key = keys[j++];
+ if (!DESCRIPTORS || propertyIsEnumerable.call(S, key)) T[key] = S[key];
+ }
+ } return T;
+} : nativeAssign;