| 558 | } |
| 559 | |
| 560 | function shouldUseNative() { |
| 561 | try { |
| 562 | if (!Object.assign) { |
| 563 | return false; |
| 564 | } |
| 565 | |
| 566 | // Detect buggy property enumeration order in older V8 versions. |
| 567 | |
| 568 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 569 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 570 | test1[5] = 'de'; |
| 571 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 572 | return false; |
| 573 | } |
| 574 | |
| 575 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 576 | var test2 = {}; |
| 577 | for (var i = 0; i < 10; i++) { |
| 578 | test2['_' + String.fromCharCode(i)] = i; |
| 579 | } |
| 580 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 581 | return test2[n]; |
| 582 | }); |
| 583 | if (order2.join('') !== '0123456789') { |
| 584 | return false; |
| 585 | } |
| 586 | |
| 587 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 588 | var test3 = {}; |
| 589 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 590 | test3[letter] = letter; |
| 591 | }); |
| 592 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 593 | 'abcdefghijklmnopqrst') { |
| 594 | return false; |
| 595 | } |
| 596 | |
| 597 | return true; |
| 598 | } catch (err) { |
| 599 | // We don't expect any of the above to throw, but better to be safe. |
| 600 | return false; |
| 601 | } |
| 602 | } |
| 603 | |
| 604 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 605 | var from; |