| 655 | } |
| 656 | |
| 657 | function shouldUseNative() { |
| 658 | try { |
| 659 | if (!Object.assign) { |
| 660 | return false; |
| 661 | } |
| 662 | |
| 663 | // Detect buggy property enumeration order in older V8 versions. |
| 664 | |
| 665 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 666 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 667 | test1[5] = 'de'; |
| 668 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 669 | return false; |
| 670 | } |
| 671 | |
| 672 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 673 | var test2 = {}; |
| 674 | for (var i = 0; i < 10; i++) { |
| 675 | test2['_' + String.fromCharCode(i)] = i; |
| 676 | } |
| 677 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 678 | return test2[n]; |
| 679 | }); |
| 680 | if (order2.join('') !== '0123456789') { |
| 681 | return false; |
| 682 | } |
| 683 | |
| 684 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 685 | var test3 = {}; |
| 686 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 687 | test3[letter] = letter; |
| 688 | }); |
| 689 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 690 | 'abcdefghijklmnopqrst') { |
| 691 | return false; |
| 692 | } |
| 693 | |
| 694 | return true; |
| 695 | } catch (err) { |
| 696 | // We don't expect any of the above to throw, but better to be safe. |
| 697 | return false; |
| 698 | } |
| 699 | } |
| 700 | |
| 701 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 702 | var from; |