NaN是假的吗？为什么NaN === false返回false

问题描述

1. 为什么 NaN === false => false，是不是NaN falsy？


2. 为什么 NaN === NaN => false，但是 !! NaN === !! NaN => true

1. Why NaN === false => false, isn't NaN falsy?
2. Why NaN === NaN => false, but !!NaN === !!NaN => true

我一直绞尽脑汁试图解决这个问题。

I've been racking my brain trying to figure this out.

推荐答案

1. Falsy 并严格等于 false 是非常不同的东西，这就是为什么一个人有 y 而不是 e 。 ;）


2. NaN 规格永远不会等于任何东西。问题的第二部分是比较 false === false ，这很有趣， true ：）

1. Falsy and being strictly equal to false are very different things, that's why one has a y instead of an e. ;)
2. NaN is spec'd to never be equal to anything. The second part of your question is comparing false === false, which is funnily enough, true :)

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