| 679 | } |
| 680 | |
| 681 | function shouldUseNative() { |
| 682 | try { |
| 683 | if (!Object.assign) { |
| 684 | return false; |
| 685 | } |
| 686 | |
| 687 | // Detect buggy property enumeration order in older V8 versions. |
| 688 | |
| 689 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 690 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 691 | test1[5] = 'de'; |
| 692 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 693 | return false; |
| 694 | } |
| 695 | |
| 696 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 697 | var test2 = {}; |
| 698 | for (var i = 0; i < 10; i++) { |
| 699 | test2['_' + String.fromCharCode(i)] = i; |
| 700 | } |
| 701 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 702 | return test2[n]; |
| 703 | }); |
| 704 | if (order2.join('') !== '0123456789') { |
| 705 | return false; |
| 706 | } |
| 707 | |
| 708 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 709 | var test3 = {}; |
| 710 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 711 | test3[letter] = letter; |
| 712 | }); |
| 713 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 714 | 'abcdefghijklmnopqrst') { |
| 715 | return false; |
| 716 | } |
| 717 | |
| 718 | return true; |
| 719 | } catch (err) { |
| 720 | // We don't expect any of the above to throw, but better to be safe. |
| 721 | return false; |
| 722 | } |
| 723 | } |
| 724 | |
| 725 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 726 | var from; |