# 差异化支持(腻子)

Three.js 包含以下方法和常量的差异化支持.

### [page:Number.EPSILON Number.EPSILON]

表示1和大于1的最小差值，可表示为 Number. [link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/EPSILON MDN reference].

### [page:Math.sign Math.sign]( [page:Number x] )

如果参数为 正数，负数，正零 或 负零, 该方法将分别返回 1, -1, 0 或 -0 . 否则, 返回 NaN. [link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sign MDN reference].

### [page:Function.prototype.name Function.prototype.name]( [page:Number x] )

返回方法的名字, 或 (在 ES6 实现之前) 为匿名方法返回一个空字符串. [link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name MDN reference].

### [page:Object.assign Object.assign]( [page:Object target], [page:Object ...sources] )

Object.assign() 方法用于从一个或多个源对象拷贝所有可枚举自身属性到目标对象. 该方法将返回目标对象. [link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign MDN reference].

## 源码

[link:https://github.com/mrdoob/three.js/blob/master/src/polyfills.js src/polyfills.js]