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Commit Description:
add model solution
Commit Description:
add model solution
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node_modules/object.assign/polyfill.js
| 51 lines
| 1.3 KiB
| application/javascript
| JavascriptLexer
|
| r789 | 'use strict'; | |||
| var implementation = require('./implementation'); | ||||
| var lacksProperEnumerationOrder = function () { | ||||
| if (!Object.assign) { | ||||
| return false; | ||||
| } | ||||
| // v8, specifically in node 4.x, has a bug with incorrect property enumeration order | ||||
| // note: this does not detect the bug unless there's 20 characters | ||||
| var str = 'abcdefghijklmnopqrst'; | ||||
| var letters = str.split(''); | ||||
| var map = {}; | ||||
| for (var i = 0; i < letters.length; ++i) { | ||||
| map[letters[i]] = letters[i]; | ||||
| } | ||||
| var obj = Object.assign({}, map); | ||||
| var actual = ''; | ||||
| for (var k in obj) { | ||||
| actual += k; | ||||
| } | ||||
| return str !== actual; | ||||
| }; | ||||
| var assignHasPendingExceptions = function () { | ||||
| if (!Object.assign || !Object.preventExtensions) { | ||||
| return false; | ||||
| } | ||||
| // Firefox 37 still has "pending exception" logic in its Object.assign implementation, | ||||
| // which is 72% slower than our shim, and Firefox 40's native implementation. | ||||
| var thrower = Object.preventExtensions({ 1: 2 }); | ||||
| try { | ||||
| Object.assign(thrower, 'xy'); | ||||
| } catch (e) { | ||||
| return thrower[1] === 'y'; | ||||
| } | ||||
| return false; | ||||
| }; | ||||
| module.exports = function getPolyfill() { | ||||
| if (!Object.assign) { | ||||
| return implementation; | ||||
| } | ||||
| if (lacksProperEnumerationOrder()) { | ||||
| return implementation; | ||||
| } | ||||
| if (assignHasPendingExceptions()) { | ||||
| return implementation; | ||||
| } | ||||
| return Object.assign; | ||||
| }; | ||||