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一个让我掉到坑里的问题:null==0 吗? #35

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cssmagic opened this Issue Feb 28, 2016 · 0 comments

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cssmagic commented Feb 28, 2016

今天在处理某个 JavaScript 函数的过程中,犯了一个错误。我下意识地认为 null==0 是成立的。

我们知道 null===0 肯定是不成立的。但 null==0 呢?

JavaScript 是弱类型语言,有一套复杂的类型转换规则。记忆中 null 转换为布尔值应该是 false,而且 0 也是这样,于是就想当然地认为这个相等是成立的。

但是,相等运算符(==)并不是把两个值转换为布尔值之后再进行比较,它有自己的一套比较规则。我查阅了《JavaScript 权威指南》,结果证明我最初的想法是错误的。

这就是今天的一点收获。同时也要承认,作为一个 JavaScript 初学者,自己的基础还是有很多薄弱的地方!

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