1 var has = require('../internals/has');
2 var ownKeys = require('../internals/own-keys');
3 var getOwnPropertyDescriptorModule = require('../internals/object-get-own-property-descriptor');
4 var definePropertyModule = require('../internals/object-define-property');
6 module.exports = function (target, source) {
7 var keys = ownKeys(source);
8 var defineProperty = definePropertyModule.f;
9 var getOwnPropertyDescriptor = getOwnPropertyDescriptorModule.f;
10 for (var i = 0; i < keys.length; i++) {
12 if (!has(target, key)) defineProperty(target, key, getOwnPropertyDescriptor(source, key));