noUnusedImports

JavaScript (and super languages)

摘要

¥Summary

• 规则生效日期：v1.3.0

  ¥Rule available since: v1.3.0

• 诊断类别：lint/correctness/noUnusedImports

  ¥Diagnostic Category: lint/correctness/noUnusedImports

• 此规则为推荐规则，默认启用。

  ¥This rule is recommended, which means is enabled by default.

• 此规则包含 unsafe 修复程序。

  ¥This rule has an unsafe fix.

• 此规则的默认严重级别为 warning。

  ¥The default severity of this rule is warning.

• 来源：

  ¥Sources:

  • 与 unused-imports/no-unused-imports 相同

    ¥Same as unused-imports/no-unused-imports

如何配置

¥How to configure

biome.json

{
  "linter": {
    "rules": {
      "correctness": {
        "noUnusedImports": "error"
      }
    }
  }
}

描述

¥Description

禁止未使用的导入。

¥Disallow unused imports.

未使用的导入可能是重构不完整造成的。代码修复可以删除与 import 相关的注释。参见最后一个无效示例。

¥Unused imports might be the result of an incomplete refactoring. The code fix can remove comments associated with an import. See the last invalid example.

请注意，未使用的导入前面的琐碎内容（例如注释或换行符）也将被删除。这样像 @ts-expect-error 这样的注释指令就不会被转移到错误的地方。

¥Note that the leading trivia, e.g., comments or newlines preceding the unused imports will also be removed. So that comment directives like @ts-expect-error won’t be transferred to a wrong place.

选项

¥Options

此规则尊重 jsxRuntime 设置，如果设置为 "reactClassic"，则会对 React 全局变量进行例外处理。

¥This rule respects the jsxRuntime setting and will make an exception for React globals if it is set to "reactClassic".

示例

¥Examples

无效

¥Invalid

import A from 'mod';

code-block.js:1:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is unused.
  
  > 1 │ import A from ‘mod’;
      │        ^
    2 │ 
  
  ℹ Unused imports might be the result of an incomplete refactoring.
  
  ℹ Unsafe fix: Remove the unused imports.
  
    1 │ import·A·from·‘mod’;
      │ --------------------

import * as A from 'mod';

code-block.js:1:13 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is unused.
  
  > 1 │ import * as A from ‘mod’;
      │             ^
    2 │ 
  
  ℹ Unused imports might be the result of an incomplete refactoring.
  
  ℹ Unsafe fix: Remove the unused imports.
  
    1 │ import·*·as·A·from·‘mod’;
      │ -------------------------

import { type A, B } from 'mod';

export { B }

code-block.ts:1:10 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Several of these imports are unused.
  
  > 1 │ import { type A, B } from ‘mod’;
      │          ^^^^^^
    2 │ 
    3 │ export { B }
  
  ℹ Unused imports might be the result of an incomplete refactoring.
  
  ℹ Unsafe fix: Remove the unused imports.
  
    1 │ import·{·type·A,·B·}·from·‘mod’;
      │          --------               

// Header comment
import /*inner comment */ A from 'mod'; // Associated comment

code-block.ts:2:27 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is unused.
  
    1 │ // Header comment
  > 2 │ import /*inner comment */ A from ‘mod’; // Associated comment
      │                           ^
    3 │ 
  
  ℹ Unused imports might be the result of an incomplete refactoring.
  
  ℹ Unsafe fix: Remove the unused imports.
  
    1   │ - //·Header·comment
    2   │ - import·/*inner·comment·*/·A·from·‘mod’;·//·Associated·comment
      1 │ + 
    3 2 │   
  

// Another header comment
import {
    // A's header comment
    type A, // A's comment
    // B's header comment
    B,
} from 'mod';

export { B }

code-block.ts:4:5 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Several of these imports are unused.
  
    2 │ import {
    3 │     // A’s header comment
  > 4 │     type A, // A’s comment
      │     ^^^^^^
    5 │     // B’s header comment
    6 │     B,
  
  ℹ Unused imports might be the result of an incomplete refactoring.
  
  ℹ Unsafe fix: Remove the unused imports.
  
     1 1 │   // Another header comment
     2 2 │   import {
     3   │ - ····//·A’s·header·comment
     4   │ - ····type·A,·//·A’s·comment
     5 3 │       // B’s header comment
     6 4 │       B,
  

有效

¥Valid

import { A, type B } from 'mod';

function f(arg: B): A {
    return new A(arg);
}

一个值得注意的例外情况是，当导入用于类型增强时。

¥One notable exception is when the import is intended to be used for type augmentation.

import type {} from '@mui/lab/themeAugmentation';

相关链接

¥Related links

• 禁用规则

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• 配置代码修复

  ¥Configure the code fix

• 规则选项

  ¥Rule options

• 源代码

  ¥Source Code

• 测试用例

  ¥Test Cases