JavaScript中是否有常量？ [英] Are there constants in JavaScript?

问题描述

有没有办法在JavaScript中使用常量？

Is there a way to use constants in JavaScript?

如果没有，指定用作常量的变量的常用做法是什么？

If not, what's the common practice for specifying variables that are used as constants?

推荐答案

自 ES2015 ，JavaScript有 const ：

Since ES2015, JavaScript has a notion of const:

const MY_CONSTANT = "some-value";

这适用于除了IE 8,9和10之外几乎所有的浏览器。有些人可能还需要启用严格模式。

This will work in pretty much all browsers except IE 8, 9 and 10. Some may also need strict mode enabled.

您可以使用 var 以及ALL_CAPS等惯例来显示如果您需要支持旧版浏览器或不需要修改某些值正在使用遗留代码：

You can use var with conventions like ALL_CAPS to show that certain values should not be modified if you need to support older browsers or are working with legacy code:

var MY_CONSTANT = "some-value";

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