Javascript：比较运算符中的操作数的顺序 [英] Javascript: Order of operands in comparison operator

问题描述

是否有特定的原因我见过许多人写的

Is there a specific reason why I have seen many people writing

if(1 === a) {...}

而不是

if(a === 1) {...}

给出了一个答案，其中我写了一些像 Array === obj.constructor 这是当有人问我他经常看到人写这样而不是 obj.constructor === Array 。

I had given an answer in which I wrote something like Array === obj.constructor which is when someone asked me that he has often seen people writing like this instead of obj.constructor === Array.

所以我用哪种方式真的很重要。

So does it really matter which way I use?

推荐答案

这是 yoda条件：

Yoda条件是这样命名的，因为条件的文字值先出现，而变量出现在第二。例如，以下是Yoda条件：

Yoda conditions are so named because the literal value of the condition comes first while the variable comes second. For example, the following is a Yoda condition:

if ("red" === color) {
    // ...
}

这被称为尤达条件，因为它读作，红色是颜色，类似于星球大战字符尤佳说话的方式。与安排操作数的其他方式比较：

This is called a Yoda condition because it reads as, "red is the color", similar to the way the Star Wars character Yoda speaks. Compare to the other way of arranging the operands:

if (color === "red") {
    // ...
}

这通常表示颜色是红色，这可能是一种更自然的方式来描述比较。

This typically reads, "color is red", which is arguably a more natural way to describe the comparison.

Yoda条件的支持者强调，错误地使用=而不是==，因为你不能分配一个文字值。这样做会导致语法错误，并会在早期被通知错误。因此，这种做法在早期编程中非常常见，因为工具尚不可用。

Proponents of Yoda conditions highlight that it is impossible to mistakenly use = instead of == because you cannot assign to a literal value. Doing so will cause a syntax error and you will be informed of the mistake early on. This practice was therefore very common in early programming where tools were not yet available.

Yoda条件的反对者指出，工具使我们更好的程序员，因为工具会捕获错误使用=而不是==（ESLint会抓住这个你）。因此，他们认为，模式的效用并不超过代码在使用Yoda条件时的可读性。

Opponents of Yoda conditions point out that tooling has made us better programmers because tools will catch the mistaken use of = instead of == (ESLint will catch this for you). Therefore, they argue, the utility of the pattern doesn’t outweigh the readability hit the code takes while using Yoda conditions.

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