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”.

我們都知道JavaScript是弱類型語言，在某些情況下，當與“ ==”進行相等性比較時，它特別落後。使用“ ==”進行比較可能會“將2個操作數中的一個強制轉換為另一種類型然後進行比較”而產生意外結果。

1 0 == ' ' //true
2 null == undefined //true
3 [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提供了三等運算符，三等運算符更加嚴格並且不會將操作數進行強制類型轉換。然而三等運算符也不是最好的解決方案，也存在問題：

1 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中有一個新的“ Object.is（）”，它更好，更精確，它具有與“ ===”相同的功能，而且在某些特殊情況下，其表現還不錯：

1 Object.is(0 , ' '); //false
2 Object.is(null, undefined); //false
3 Object.is([1], true); //false
4 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團隊不認為"Object.is()"比“ ===”更“嚴格”，應該考慮該方法如何處理NaN，-0和+0，但總的來說，我認為這是一種最佳實踐。

Now this table illustrates..

下表所示：

參考:

Object.is() - JavaScript | MDN

Equality comparisons and sameness