ESLint Plugin No Barrel Files

1.3.1 verified Sat Apr 25 auth: no javascript

ESLint plugin (v1.3.1) that disallows barrel files — re-export modules that aggregate and re-export other modules. Barrel files are known to slow down builds/tests, cause circular dependencies, and hinder tree shaking. This plugin provides a single rule `no-barrel-files` that flags patterns like `export * from './foo'` or re-importing a default and re-exporting it. Supports flat config (ESLint 9+) and legacy config (ESLint 8). Actively maintained with TypeScript type declarations. Alternative to manual code review or other linting rules that partially address barrel files.

Common errors

error Error: Failed to load plugin 'no-barrel-files' declared in '.eslintrc': Cannot find module 'eslint-plugin-no-barrel-files' ↓

cause Plugin not installed or not in node_modules.

fix

Run npm install eslint-plugin-no-barrel-files --save-dev.

error Configuration for rule "no-barrel-files/no-barrel-files" is invalid: Value "error" should be one of 0, 1, 2. ↓

cause Rule severity incorrectly set (e.g., as string 'error' instead of number 2).

fix

Set severity to 2 (or 'error') in an array: ['error'] or 2.

error TypeError: noBarrelFiles.flat is not a function ↓

cause Using deprecated `flat` export which is no longer a function but an array.

fix

Use noBarrelFiles.configs.recommended instead of noBarrelFiles.flat.

Warnings

breaking In v1.0.0, the flat config export changed from `plugin.flat` to `plugin.configs.recommended`. If using `plugin.flat`, update to `configs.recommended`. ↓

fix Replace `noBarrelFiles.flat` with `noBarrelFiles.configs.recommended` in flat config.

deprecated The `flat` export is deprecated since v1.0.0. It will be removed in a future major version. ↓

fix Use `configs.recommended` instead of `flat`.

gotcha Legacy config users must use the plugin prefix in rule names: `'no-barrel-files/no-barrel-files'`. Using just `'no-barrel-files'` will not work. ↓

fix Set rule name as `'no-barrel-files/no-barrel-files'`.

gotcha The rule does not flag `export { default } from './foo'` (named export with alias 'default'); only `export { default as Moo } from './Moo'` is flagged. ↓

fix If needed, manually audit or extend the rule. Check plugin issue tracker for potential updates.

Install

npm install eslint-plugin-no-barrel-files

yarn add eslint-plugin-no-barrel-files

pnpm add eslint-plugin-no-barrel-files

Imports

default (plugin object)
wrong
```
const noBarrelFiles = require('eslint-plugin-no-barrel-files')
```
correct
```
import noBarrelFiles from 'eslint-plugin-no-barrel-files'
```
ESM default import; CommonJS require works but may not provide correct types. For flat config (ESLint 9+), use default import.
flat config
wrong
```
noBarrelFiles.flat
```
correct
```
noBarrelFiles.configs.recommended
```
Since v1.0.0, `configs.recommended` is the canonical flat config. `flat` export maintained for backwards compatibility but deprecated.
legacy config
wrong
```
noBarrelFiles.configs.recommended
```
correct
```
noBarrelFiles.configs['legacy-recommended']
```
For ESLint 8 legacy config, use `legacy-recommended`. The `recommended` config is for flat config (ESLint 9+).

Quickstart

Shows two ESLint configurations: legacy CommonJS for ESLint 8 and modern ESM flat config for ESLint 9+. Enables the single rule that flags barrel file patterns.

// .eslintrc.cjs (legacy ESLint 8)
module.exports = {
  plugins: ['no-barrel-files'],
  rules: {
    'no-barrel-files/no-barrel-files': 'error'
  }
};

// eslint.config.js (flat ESLint 9+)
import noBarrelFiles from 'eslint-plugin-no-barrel-files';

export default [
  ...noBarrelFiles.configs.recommended,
  {
    rules: {
      // Override or add more rules
    }
  }
];