eslint-config-unjs

0.6.2 verified Sat Apr 25 auth: no javascript

ESLint flat config preset for unjs projects, currently at v0.6.2. It integrates eslint recommended rules, eslint-plugin-unicorn, typescript-eslint, and eslint-plugin-markdown. This package is designed exclusively for ESLint's new flat config system (ESLint v9+). It provides a single exported function that accepts options for ignoring paths, overriding rules, and customizing markdown-specific rules. The package ships TypeScript types and is actively maintained with frequent dependency updates. Key differentiators include its tailored rule set for the unjs ecosystem and support for type-generated rule configurations via eslint-typegen.

Common errors

error Cannot find module 'eslint-config-unjs' or its corresponding type declarations. ↓

cause Missing npm install or using CommonJS require.

fix

Run npm install -D eslint-config-unjs and use import (ESM) instead of require.

error Error: Failed to load config 'eslint-config-unjs' to extend from. ↓

cause Attempting to use preset in legacy .eslintrc with 'extends' field.

fix

Migrate to flat config (eslint.config.mjs) and use import unjs from 'eslint-config-unjs'.

error Parsing error: The keyword 'export' is reserved. ↓

cause ES module syntax used in a CommonJS file (e.g., .js without type: module).

fix

Rename file to .mjs or add "type": "module" in package.json.

Warnings

breaking ESLint flat config only: This preset does not support legacy .eslintrc configuration. Requires ESLint v9 and flat config. ↓

fix Migrate to flat config: use eslint.config.mjs and call import unjs from 'eslint-config-unjs'.

breaking v0.3.0 dropped support for ESLint <9 and legacy config. All previous versions (0.2.x) are incompatible. ↓

fix Upgrade ESLint to v9 and rewrite config as flat config.

deprecated Some unicorn rules may change between minor versions. Check changelog when upgrading. ↓

fix Review unicorn plugin updates and adjust rules accordingly.

gotcha The unjs function returns an array, not a single object. Attempting to use it directly as a config object will fail. ↓

fix Spread the result if merging with other configs: export default [ ...unjs(...), ...otherConfigs ];

gotcha Types for rules are not auto-generated in this package; you must use eslint-typegen separately. ↓

fix Install @antfu/eslint-typegen and run it to generate rule types.

Install

npm install eslint-config-unjs

yarn add eslint-config-unjs

pnpm add eslint-config-unjs

Imports

default
wrong
```
const unjs = require('eslint-config-unjs')
```
correct
```
import unjs from 'eslint-config-unjs'
```
ESLint flat config requires ES modules; CommonJS require may fail or need .default.
unjs function usage
wrong
```
export default unjs() // missing object argument
```
correct
```
export default unjs({ ignores: [], rules: {} })
```
The function expects an options object (even if empty) to configure ignores, rules, and markdown.

TypeScript type imports

wrong

import { UnjsConfig } from 'eslint-config-unjs' // type import used as value

correct

import type { UnjsConfig } from 'eslint-config-unjs'

Config types are exported for TypeScript projects; importing as value will cause runtime error.

chaining multiple configs

wrong

export default unjs({ ignores: [] }, otherConfigs) // cannot pass additional configs as second argument

correct

export default [...unjs({ ignores: [] }), ...otherConfigs]

The function returns a single config array; to merge multiple configs, spread the result.

Quickstart

Creates an ESLint flat config using unjs preset with custom ignores, rule overrides, and markdown-specific overrides.

import unjs from 'eslint-config-unjs';

export default unjs({
  ignores: [
    'dist',
    'node_modules',
    '*.config.*',
  ],
  rules: {
    'unicorn/filename-case': ['error', { case: 'kebabCase' }],
    '@typescript-eslint/no-unused-vars': 'warn',
  },
  markdown: {
    rules: {
      'unicorn/filename-case': 'off',
    },
  },
});