| 448 | } |
| 449 | |
| 450 | function shouldUseNative() { |
| 451 | try { |
| 452 | if (!Object.assign) { |
| 453 | return false; |
| 454 | } |
| 455 | |
| 456 | // Detect buggy property enumeration order in older V8 versions. |
| 457 | |
| 458 | // https://bugs.chromium.org/p/v8/issues/detail?id=4118 |
| 459 | var test1 = new String('abc'); // eslint-disable-line no-new-wrappers |
| 460 | test1[5] = 'de'; |
| 461 | if (Object.getOwnPropertyNames(test1)[0] === '5') { |
| 462 | return false; |
| 463 | } |
| 464 | |
| 465 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 466 | var test2 = {}; |
| 467 | for (var i = 0; i < 10; i++) { |
| 468 | test2['_' + String.fromCharCode(i)] = i; |
| 469 | } |
| 470 | var order2 = Object.getOwnPropertyNames(test2).map(function (n) { |
| 471 | return test2[n]; |
| 472 | }); |
| 473 | if (order2.join('') !== '0123456789') { |
| 474 | return false; |
| 475 | } |
| 476 | |
| 477 | // https://bugs.chromium.org/p/v8/issues/detail?id=3056 |
| 478 | var test3 = {}; |
| 479 | 'abcdefghijklmnopqrst'.split('').forEach(function (letter) { |
| 480 | test3[letter] = letter; |
| 481 | }); |
| 482 | if (Object.keys(Object.assign({}, test3)).join('') !== |
| 483 | 'abcdefghijklmnopqrst') { |
| 484 | return false; |
| 485 | } |
| 486 | |
| 487 | return true; |
| 488 | } catch (err) { |
| 489 | // We don't expect any of the above to throw, but better to be safe. |
| 490 | return false; |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | module.exports = shouldUseNative() ? Object.assign : function (target, source) { |
| 495 | var from; |