eslint-plugin-fast-import

2.2.1 verified Sat Apr 25 auth: no javascript

An ESLint plugin for validating imports and exports, leveraging a novel algorithm with the OXC Rust-based parser for high performance. Current stable version is 2.2.1, with a rapid release cadence. It offers an editor mode that keeps in-memory data structures updated with filesystem changes, preventing stale errors. Unlike eslint-plugin-import and eslint-plugin-import-x, it does not support user-supplied resolvers and only analyzes first-party code within rootDir. It includes rules like no-cycle, no-entry-point-imports, no-external-barrel-reexports, and no-named-as-default. Requires ESLint >= 9.0.0 and ESM-only codebases.

Common errors

error Error: Cannot find module 'eslint-plugin-fast-import' ↓

cause Package not installed or missing from dependencies.

fix

Run 'npm install --save-dev eslint-plugin-fast-import' and ensure it's in package.json.

error ESLint couldn't determine the plugin 'fast-import' uniquely. ↓

cause Multiple versions or conflicting names in plugins object.

fix

Use a unique key, e.g., plugins: { 'fast-import': fastImport }.

error Configuration for rule "fast-import/no-cycle" is invalid: Value "warn" is not allowed. ↓

cause Rule severity must be 'off', 'warn', or 'error', or an array.

fix

Set rule to 'error', 'warn', 'off', or ['warn', { ... }].

error TypeError: Cannot read properties of undefined (reading 'rootDir') ↓

cause fast-import settings not defined or rootDir missing.

fix

Add settings: { 'fast-import': { rootDir: __dirname } } to ESLint config.

Warnings

breaking Version 2.0.0 dropped support for ESLint <= 8 and CommonJS. Flat config and ESM are required. ↓

fix Upgrade to ESLint 9+ and use flat config with ESM imports.

gotcha rootDir setting is required; all first-party code must reside under rootDir. Files outside are not analyzed. ↓

fix Set rootDir to the root of your project (e.g., path.resolve(__dirname, 'src')).

gotcha CommonJS (require, module.exports) is not supported. Only ESM import/export syntax is analyzed. ↓

fix Convert your codebase to ESM syntax.

gotcha Barrel re-exports of third-party modules are ignored; rules like no-external-barrel-reexports only apply to first-party code. ↓

fix For third-party re-exports, manually check or use a different plugin.

deprecated The 'all' configuration is deprecated in v2; use 'recommended' and opt-in to additional rules individually. ↓

fix Switch to configs.recommended and add extra rules as needed.

Install

npm install eslint-plugin-fast-import

yarn add eslint-plugin-fast-import

pnpm add eslint-plugin-fast-import

Imports

default

wrong

const fastImport = require('eslint-plugin-fast-import')

correct

import fastImport from 'eslint-plugin-fast-import'

CommonJS require is not supported; the plugin is ESM-only.

rules

wrong

import { noCycle } from 'eslint-plugin-fast-import'

correct

import { rules } from 'eslint-plugin-fast-import'

Individual rules are not exported; access via rules object.

configs

wrong

import recommended from 'eslint-plugin-fast-import'

correct

import { configs } from 'eslint-plugin-fast-import'

Use configs.recommended or configs.all for predefined configurations.

getESMInfo
```
import { getESMInfo } from 'eslint-plugin-fast-import'
```
Utility for rule authors to access ESM analysis context.

Quickstart

Configuring eslint-plugin-fast-import with recommended rules and settings including rootDir and alias.

// Install: npm install --save-dev eslint-plugin-fast-import

// eslint.config.js (flat config)
import fastImport from 'eslint-plugin-fast-import';

export default [
  {
    plugins: { 'fast-import': fastImport },
    rules: {
      'fast-import/no-cycle': 'error',
      'fast-import/no-entry-point-imports': 'error',
      'fast-import/no-external-barrel-reexports': 'error',
      'fast-import/no-named-as-default': 'error',
    },
    settings: {
      'fast-import': {
        rootDir: __dirname, // required
        alias: { '@': './src' },
        mode: process.env.CI ? 'build' : 'editor',
      },
    },
  },
];