为什么你应该使用 Object.is() 进行相等性比较(译)

Title: Why you should use Object.is() in equality comparison

Author: TarekAlQaddy

Website: https://www.jstips.co/en/javascript/why-you-should-use-Object.is()-in-equality-comparison/

---

We all know that JavaScript is loosely typed and in some cases it fall behind specially when it comes to equality comparison with ‘==’, comparing with ‘==’ gives unexpected results due to whats called coercion or casting “converting one of the 2 operands to the other’s type then compare”.

我们都知道JavaScript是弱类型语言，在某些情况下，当与“ ==”进行相等性比较时，它特别落后。使用“ ==”进行比较可能会“将2个操作数中的一个强制转换为另一种类型然后进行比较”而产生意外结果。

 0 == ' ' //true
 null == undefined //true
 [1] == true //true

So they provided us with the triple equal operator ‘===’ which is more strict and does not coerce operands, However comparing with ‘===’ is not the best solution you can get:

因此Javascript提供了三等运算符，三等运算符更加严格并且不会将操作数进行强制类型转换。然而三等运算符也不是最好的解决方案，也存在问题：

 NaN === NaN //false

The great news that in ES6 there is the new ‘Object.is()’ which is better and more precise it has the same features as ‘===’ and moreover it behaves well in some special cases:

好消息是，在ES6中有一个新的“ Object.is（）”，它更好，更精确，它具有与“ ===”相同的功能，而且在某些特殊情况下，其表现还不错：

 Object.is(0 , ' '); //false
 Object.is(null, undefined); //false
 Object.is([1], true); //false
 Object.is(NaN, NaN); //true

Mozilla team doesn’t think that Object.is is “stricter” than ‘===’ they say that we should think of how this method deal with NaN, -0 and +0 but overall I think it is now a good practice in real applications.

Mozilla团队不认为"Object.is()"比“ ===”更“严格”，应该考虑该方法如何处理NaN，-0和+0，但总的来说，我认为这是一种最佳实践。

Now this table illustrates..

下表所示：

参考:

Object.is() - JavaScript | MDN

Equality comparisons and sameness