| 778 | } |
| 779 | |
| 780 | function shouldUseNative() { |
| 781 | try { |
| 782 | if (!Object.assign) { |
| 783 | return false; |
| 784 | } |
| 785 | |
| 786 | // Detect buggy property enumeration order in older V8 versions. |
| 787 | |
| 788 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 789 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 790 | test1[5] = 'de'; |
| 791 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 792 | return false; |
| 793 | } |
| 794 | |
| 795 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 796 | var test2 = {}; |
| 797 | for (var i = 0; i < 10; i++) { |
| 798 | test2['_' + String.fromCharCode(i)] = i; |
| 799 | } |
| 800 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 801 | return test2[n]; |
| 802 | }); |
| 803 | if (order2.join('') !== '0123456789') { |
| 804 | return false; |
| 805 | } |
| 806 | |
| 807 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 808 | var test3 = {}; |
| 809 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 810 | test3[letter] = letter; |
| 811 | }); |
| 812 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 813 | 'abcdefghijklmnopqrst') { |
| 814 | return false; |
| 815 | } |
| 816 | |
| 817 | return true; |
| 818 | } catch (err) { |
| 819 | // We don't expect any of the above to throw, but better to be safe. |
| 820 | return false; |
| 821 | } |
| 822 | } |
| 823 | |
| 824 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 825 | var from; |