base-js

> Base ESLint flat config for JavaScript-only projects. Foundation extended by @jmlweb/eslint-config-base.

> 🔧 Maintenance mode: only dependency and security updates, no new rules. For new projects use @jmlweb/oxlint-config-base. To move an existing project, see the migration guide.

✨ Features

• 🎯 Recommended rules: @eslint/js recommended for modern JavaScript (ES modules)
• 📦 Import sorting: imports and exports sorted by eslint-plugin-simple-import-sort
• 🎨 Prettier compatible: disables rules that conflict with Prettier
• 🌐 Environment agnostic: no Node.js or browser globals by default
• 🔧 Composable: extended by the TypeScript, React, Node.js and Astro configs

📦 Installation

npm install --save-dev @jmlweb/eslint-config-base-js eslint @eslint/js eslint-config-prettier eslint-plugin-simple-import-sort

> 💡 Upgrading? See the Migration Guide.

🚀 Quick Start

eslint.config.js

import baseJsConfig from '@jmlweb/eslint-config-base-js';

export default [
  ...baseJsConfig,
  // Project-specific overrides
];

💡 Examples

Overrides and ignores

eslint.config.js

import baseJsConfig from '@jmlweb/eslint-config-base-js';

export default [
  ...baseJsConfig,
  {
    files: ['**/*.test.js', '**/*.spec.js'],
    rules: {
      'no-console': 'off',
    },
  },
  {
    ignores: ['dist/', 'build/', 'node_modules/'],
  },
];

Node.js globals

eslint.config.js

import baseJsConfig from '@jmlweb/eslint-config-base-js';
import globals from 'globals';

export default [
  ...baseJsConfig,
  {
    languageOptions: {
      globals: globals.node,
    },
  },
];

Browser globals

eslint.config.js

import baseJsConfig from '@jmlweb/eslint-config-base-js';
import globals from 'globals';

export default [
  ...baseJsConfig,
  {
    languageOptions: {
      globals: globals.browser,
    },
  },
];

globals is not a peer dependency; install it with npm install --save-dev globals.

📋 Configuration Details

Setting	Value
Files	**/*.js, **/*.mjs, **/*.cjs
ecmaVersion	latest
sourceType	module
Rules	@eslint/js recommended
Import sorting	simple-import-sort/imports: error
Export sorting	simple-import-sort/exports: error
Prettier	eslint-config-prettier rules applied

🔄 Import Sorting

Imports are grouped as side effects, Node.js built-ins and external packages, internal absolute imports, then relative imports.

Before:

import './styles.css';
import { Component } from './component';
import React from 'react';
import fs from 'fs';

After eslint --fix:

import './styles.css';
import fs from 'fs';
import React from 'react';
import { Component } from './component';

🎯 When to Use

• ✅ JavaScript-only projects (no TypeScript)
• ✅ Modern ESLint 9 or 10 flat config
• ✅ A foundation for your own shared config

For TypeScript projects use @jmlweb/eslint-config-base. For new projects of any kind prefer @jmlweb/oxlint-config-base.

🔧 Extending the Configuration

Spread the config, then add objects after it. Later entries win.

eslint.config.js

import baseJsConfig from '@jmlweb/eslint-config-base-js';

export default [
  ...baseJsConfig,
  {
    files: ['**/*.test.js'],
    rules: {
      'no-console': 'off',
    },
  },
];

📝 Usage with Scripts

{
  "scripts": {
    "lint": "eslint .",
    "lint:fix": "eslint . --fix"
  }
}

npm run lint

📋 Requirements

• Node.js >= 22.12.0
• ESLint ^9.0.0 || ^10.0.0 (flat config)

📦 Peer Dependencies

• eslint (^9.0.0 || ^10.0.0)
• @eslint/js (^9.0.0 || ^10.0.0)
• eslint-config-prettier (^9.1.0 || ^10.0.0)
• eslint-plugin-simple-import-sort (^12.0.0 || ^13.0.0 || ^14.0.0)

No typescript-eslint needed.

🔗 Related Packages

• @jmlweb/eslint-config-base: TypeScript config that extends this package (maintenance mode)
• @jmlweb/oxlint-config-base: Oxlint equivalent, recommended for new projects
• @jmlweb/prettier-config-base: Prettier config (maintenance mode)

🔄 Migration Guide

1.x to 2.0

Node.js 18 and 20 are end-of-life. Node.js >= 22.12.0 is now required: it is the first Node.js 22 release that can require() ES modules without a flag, which the CommonJS build needs to load ESM-only plugins.

1. Upgrade Node.js to 22.12.0 or later.
2. Update the package: npm install --save-dev @jmlweb/eslint-config-base-js@latest.

See the Changelog.

📄 License

MIT