object-assign.js
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'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.github.io/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 = {};
// eslint-disable-next-line no-undef
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
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;