noUselessEmptyExport (JavaScript)

Language JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/complexity/noUselessEmptyExport
This rule is recommended, meaning it is enabled by default.
This rule has a safe fix.
The default severity of this rule is information.
Sources:
- Same as @typescript-eslint/no-useless-empty-export

How to configure

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{
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  "linter": {
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    "rules": {
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      "complexity": {
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        "noUselessEmptyExport": "error"
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      }
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    }
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  }
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}

Description

Disallow empty exports that don’t change anything in a module file.

An empty export {} is sometimes useful to turn a file that would otherwise be a script into a module. Per the TypeScript Handbook Modules page:

In TypeScript, just as in ECMAScript 2015, any file containing a top-level import or export is considered a module. Conversely, a file without any top-level import or export declarations is treated as a script whose contents are available in the global scope.

However, an export {} statement does nothing if there are any other top-level import or export in the file.

Examples

Invalid

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import { A } from "module";
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export {};

code-block.js:2:1 lint/complexity/noUselessEmptyExport  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This empty export is useless because there's another export or import.
  
    1 │ import { A } from "module";
  > 2 │ export {};
      │ ^^^^^^^^^^
    3 │ 
  
  ℹ This import makes useless the empty export.
  
  > 1 │ import { A } from "module";
      │ ^^^^^^
    2 │ export {};
    3 │ 
  
  ℹ Safe fix: Remove this useless empty export.
  
    1 1 │   import { A } from "module";
    2   │ - export·{};
    3 2 │

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export const A = 0;
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export {};

code-block.js:2:1 lint/complexity/noUselessEmptyExport  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This empty export is useless because there's another export or import.
  
    1 │ export const A = 0;
  > 2 │ export {};
      │ ^^^^^^^^^^
    3 │ 
  
  ℹ This export makes useless the empty export.
  
  > 1 │ export const A = 0;
      │ ^^^^^^
    2 │ export {};
    3 │ 
  
  ℹ Safe fix: Remove this useless empty export.
  
    1 1 │   export const A = 0;
    2   │ - export·{};
    3 2 │

Valid

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export {};