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prefer-as-const

Enforce the use of as const over literal type.

✅

在 ESLint 配置 中扩展"plugin:@typescript-eslint/recommended" 可启用此规则。

🔧

此规则报告的一些问题可通过 --fix ESLint 命令行选项自动修复。

💡

此规则报告的一些问题可以通过编辑器 建议 手动修复。


有两种常见方法可以告诉 TypeScript 应将字面量值解释为其字面量类型（例如 2）而不是一般原始类型（例如 number）；

英：There are two common ways to tell TypeScript that a literal value should be interpreted as its literal type (e.g. 2) rather than general primitive type (e.g. number);

  • as const： 告诉 TypeScript 自动推断字面量类型
  • as 与字面量类型： 明确地告诉 TypeScript 字面量类型

通常首选 as const，因为它不需要重新键入字面量值。 此规则报告何时可以用 as const 替换具有显式字面量类型的 as。

英：as const is generally preferred, as it doesn't require re-typing the literal value. This rule reports when an as with an explicit literal type can be replaced with an as const.

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/prefer-as-const": "error"
  }
};
在线运行试试这个规则 ↗

示例​

let bar: 2 = 2;
let foo = <'bar'>'bar';
let foo = { bar: 'baz' as 'baz' };
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何时不使用它​

如果你不关心代码中使用哪种样式的字面量断言，那么你将不需要此规则。

英：If you don't care about which style of literals assertions is used in your code, then you will not need this rule.

但是，请记住，不一致的风格可能会损害项目的可读性。 我们建议为此规则选择一个最适合你的项目的选项。

英：However, keep in mind that inconsistent style can harm readability in a project. We recommend picking a single option for this rule that works best for your project.

选项​

该规则不可配置。

资源​