JavaScript中有常量吗?

Are there constants in JavaScript?(JavaScript中有常量吗?)

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?

如果不是，指定用作常量的变量的常见做法是什么?

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

推荐答案

自ES2015，JavaScript 有一个 <代码>常量:

Since ES2015, JavaScript has a notion of const:

const MY_CONSTANT = "some-value";

这将适用于几乎所有浏览器，除了 IE 8、9 和 10.有些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.

您可以将 var 与 ALL_CAPS 等约定一起使用，以表明如果您需要支持旧版浏览器或使用旧代码，则不应修改某些值:

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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