| 720 | } |
| 721 | |
| 722 | function shouldUseNative() { |
| 723 | try { |
| 724 | if (!Object.assign) { |
| 725 | return false; |
| 726 | } |
| 727 | |
| 728 | // Detect buggy property enumeration order in older V8 versions. |
| 729 | |
| 730 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 731 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 732 | test1[5] = 'de'; |
| 733 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 734 | return false; |
| 735 | } |
| 736 | |
| 737 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 738 | var test2 = {}; |
| 739 | for (var i = 0; i < 10; i++) { |
| 740 | test2['_' + String.fromCharCode(i)] = i; |
| 741 | } |
| 742 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 743 | return test2[n]; |
| 744 | }); |
| 745 | if (order2.join('') !== '0123456789') { |
| 746 | return false; |
| 747 | } |
| 748 | |
| 749 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 750 | var test3 = {}; |
| 751 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 752 | test3[letter] = letter; |
| 753 | }); |
| 754 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 755 | 'abcdefghijklmnopqrst') { |
| 756 | return false; |
| 757 | } |
| 758 | |
| 759 | return true; |
| 760 | } catch (err) { |
| 761 | // We don't expect any of the above to throw, but better to be safe. |
| 762 | return false; |
| 763 | } |
| 764 | } |
| 765 | |
| 766 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 767 | var from; |