缩短JS if或statement [英] Shorten JS if or statement

问题描述

反正可以用Javascript来简化如下代码: if(x == 1 || x == 2 || x == 3 || x == 4)到if(x ==(1 || 2 || 3 || 4))吗?

Is there anyway to shorten something like this in Javascript: if (x == 1 || x == 2 || x == 3 || x == 4) to something like if (x == (1 || 2 || 3 || 4)) ?

推荐答案

您可以使用 Array.indexOf

[1,2,3,4].indexOf(x) !== -1

您还可以将对象用作某种哈希图:

You can also use objects as some kind of hash map:

//Note: Keys will be coerced to strings so
// don't use this method if you are looking for an object or if you need
// to distinguish the number 1 from the string "1"
my_values = {1:true, 2:true, 3:true, 'foo':true}
my_values.hasOwnProperty('foo')

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顺便说一句，在大多数情况下，您应该使用"==="严格相等运算符，而不是 == 运算符.使用"=="进行比较可能会产生很多复杂的类型强制，有时您会得到令人惊讶的结果.

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By the way, in most cases you should usi the "===" strict equality operator instead of the == operator. Comparison using "==" may do lots of complicated type coercion and you can get surprising results sometimes.

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