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noImportCycles

摘要

Section titled “摘要”

¥Summary

如何配置

Section titled “如何配置”

¥How to configure

biome.json
{
  "linter": {
    "rules": {
      "nursery": {
        "noImportCycles": "error"
      }
    }
  }
}

描述

Section titled “描述”

¥Description

防止循环导入。

¥Prevent import cycles.

当一个文件直接或间接地导入另一个文件，而该文件又再次导入了原始文件时，此规则会发出警告。

¥This rule warns when a file imports another file that, either directly or indirectly, imports the original file again.

循环引用可能导致出现意外的 undefined 符号，这通常被认为是不良的代码习惯。

¥Cycles can lead to symbols that are unexpectedly undefined and are generally considered poor code hygiene.

如果检测到循环引用，建议移动代码，使导入语句单向传递，即不要将 “back” 指向导入文件。

¥If a cycle is detected, it is advised to move code such that imports only go in a single direction, i.e. they don’t point “back” to the importing file.

但是，允许导入自身文件，并且该规则不会针对这些用例触发。这允许将函数/变量封装到命名空间中，而不是使用静态类（触发 noStaticOnlyClass）。

¥However, files that import themselves are allowed, and the rule won’t trigger for these use cases. This allows for encapsulation of functions/variables into a namespace instead of using a static class (triggers noStaticOnlyClass).

示例

Section titled “示例”

¥Examples

无效

Section titled “无效”

¥Invalid

foobar.js
import { baz } from "./baz.js";


export function foo() {
    baz();
}


export function bar() {
    console.log("foobar");
}
/foobar.js:1:21 lint/nursery/noImportCycles ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is part of a cycle.
  
  > 1 │ import { baz } from “./baz.js”;
      │                     ^^^^^^^^^^
    2 │ 
    3 │ export function foo() {
  
  ℹ This import resolves to /baz.js
        … which imports /foobar.js
        … which is the file we’re importing from.
baz.js
import { bar } from "./foobar.js";


export function baz() {
    bar();
}
/baz.js:1:21 lint/nursery/noImportCycles ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is part of a cycle.
  
  > 1 │ import { bar } from “./foobar.js”;
      │                     ^^^^^^^^^^^^^
    2 │ 
    3 │ export function baz() {
  
  ℹ This import resolves to /foobar.js
        … which imports /baz.js
        … which is the file we’re importing from.

有效

Section titled “有效”

¥Valid

foo.js
import { baz } from "./baz.js";


export function foo() {
    baz();
}
bar.js
export function bar() {
    console.log("foobar");
}
baz.js
import { bar } from "./bar.js";


export function baz() {
    bar();
}
foobaz.js
export function foo() {
    console.log("foobaz");
}


export * as baz from './foobaz.js';


import { baz } from './foobaz.js';
types.ts
import type { bar } from "./qux.ts";


export type Foo = {
  bar: typeof bar;
};
qux.ts
import type { Foo } from "./types.ts";


export function bar(foo: Foo) {
    console.log(foo);
}

选项

Section titled “选项”

¥Options

该规则提供了如下所述的选项。

¥The rule provides the options described below.

ignoreTypes

Section titled “ignoreTypes”

在发现循环导入时，忽略仅类型导入。编译器会移除仅类型导入 (import type)，从而在运行时减少一个导入循环。请注意，命名类型导入 (import { type Foo }) 不被视为仅类型导入，因为如果启用了 verbatimModuleSyntax 选项，编译器不会将其移除。默认启用。

¥Ignores type-only imports when finding an import cycle. A type-only import (import type) will be removed by the compiler, so it cuts an import cycle at runtime. Note that named type imports (import { type Foo }) aren’t considered as type-only because it’s not removed by the compiler if the verbatimModuleSyntax option is enabled. Enabled by default.

biome.json
{
  "linter": {
    "rules": {
      "nursery": {
        "noImportCycles": {
          "options": {
            "ignoreTypes": false
          }
        }
      }
    }
  }
}

无效

Section titled “无效”

¥Invalid

types.ts
import type { bar } from "./qux.ts";


export type Foo = {
  bar: typeof bar;
};
qux.ts
import type { Foo } from "./types.ts";


export function bar(foo: Foo) {
    console.log(foo);
}
/qux.ts:1:26 lint/nursery/noImportCycles ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This import is part of a cycle.
  
  > 1 │ import type { Foo } from “./types.ts”;
      │                          ^^^^^^^^^^^^
    2 │ 
    3 │ export function bar(foo: Foo) {
  
  ℹ This import resolves to /types.ts
        … which imports /qux.ts
        … which is the file we’re importing from.

相关链接

Section titled “相关链接”

¥Related links

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