| 998 | } |
| 999 | |
| 1000 | function shouldUseNative() { |
| 1001 | try { |
| 1002 | if (!Object.assign) { |
| 1003 | return false; |
| 1004 | } |
| 1005 | |
| 1006 | // Detect buggy property enumeration order in older V8 versions. |
| 1007 | |
| 1008 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 1009 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 1010 | test1[5] = 'de'; |
| 1011 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 1012 | return false; |
| 1013 | } |
| 1014 | |
| 1015 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 1016 | var test2 = {}; |
| 1017 | for (var i = 0; i < 10; i++) { |
| 1018 | test2['_' + String.fromCharCode(i)] = i; |
| 1019 | } |
| 1020 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 1021 | return test2[n]; |
| 1022 | }); |
| 1023 | if (order2.join('') !== '0123456789') { |
| 1024 | return false; |
| 1025 | } |
| 1026 | |
| 1027 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 1028 | var test3 = {}; |
| 1029 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 1030 | test3[letter] = letter; |
| 1031 | }); |
| 1032 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 1033 | 'abcdefghijklmnopqrst') { |
| 1034 | return false; |
| 1035 | } |
| 1036 | |
| 1037 | return true; |
| 1038 | } catch (err) { |
| 1039 | // We don't expect any of the above to throw, but better to be safe. |
| 1040 | return false; |
| 1041 | } |
| 1042 | } |
| 1043 | |
| 1044 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 1045 | var from; |