Strict ESLint rules for libs-for-dev repositories

The strictest ESLint configuration for modern JavaScript/TypeScript development

Table of Contents

• Strict ESLint rules for libs-for-dev repositories
  • Table of Contents
  • Features
  • Requirements
  • Installation
    • Basic Installation
    • Peer Dependencies
      • Required for all projects:
      • For React projects:
      • For Vue projects:
      • For Svelte projects:
    • Complete Installation Examples
      • React + TypeScript project:
      • Vue + TypeScript project:
      • Svelte + TypeScript project:
  • Supported File Types
  • Usage
    • Basic Configuration
    • TypeScript Project
    • Vue.js Project
    • Customization
  • ESLint Rules Overview
    • Code Quality Rules
    • Style Rules
    • TypeScript Specific
    • React Specific
    • Vue Specific
    • Testing (Vitest)
    • Documentation
    • Import/Export
    • Performance
    • Regular Expressions
    • Package.json

Features

• 🎯 Zero-config setup for common project types
• 🔧 Comprehensive rule sets for JS, TS, Vue, React, Svelte and more
• 🎨 Built-in stylistic rules (no Prettier needed)
• 📝 Strict file naming conventions
• ✨ Best practices enforcement

Requirements

• Node.js >=24.7.0
• ESLint >=9.0.0 <10.0.0

Installation

⚠️ Important: This package uses peer dependencies. You must install the required peer dependencies separately based on your project type (React, Vue, Svelte, etc.). See the Peer Dependencies section below for detailed installation instructions.

Basic Installation

Install with your favorite package manager:

# npm
npm install --save-dev @libs-for-dev/eslint-rules

# yarn
yarn add -D @libs-for-dev/eslint-rules

# pnpm
pnpm add -D @libs-for-dev/eslint-rules

# bun
bun add -D @libs-for-dev/eslint-rules

Peer Dependencies

This package requires several peer dependencies that must be installed separately based on your project type:

Required for all projects:

# ESLint (required)
npm install --save-dev eslint@^9.0.0

For React projects:

npm install --save-dev eslint-plugin-react@^7.37.5 eslint-plugin-react-hooks@^5.2.0 eslint-plugin-react-perf@^3.3.3 react@^19.1.1

For Vue projects:

npm install --save-dev eslint-plugin-vue@^10.4.0 eslint-plugin-vue-scoped-css@^2.12.0 eslint-plugin-vuejs-accessibility@^2.4.1 vue@^3.5.21 vue-eslint-parser@^10.2.0

For Svelte projects:

npm install --save-dev eslint-plugin-svelte@^3.12.3 svelte@^5.38.10 svelte-eslint-parser@^1.3.2

Complete Installation Examples

React + TypeScript project:

npm install --save-dev @libs-for-dev/eslint-rules eslint@^9.0.0 eslint-plugin-react@^7.37.5 eslint-plugin-react-hooks@^5.2.0 eslint-plugin-react-perf@^3.3.3 react@^19.1.1 typescript@^5.9.2

Vue + TypeScript project:

npm install --save-dev @libs-for-dev/eslint-rules eslint@^9.0.0 eslint-plugin-vue@^10.4.0 eslint-plugin-vue-scoped-css@^2.12.0 eslint-plugin-vuejs-accessibility@^2.4.1 vue@^3.5.21 vue-eslint-parser@^10.2.0 typescript@^5.9.2

Svelte + TypeScript project:

npm install --save-dev @libs-for-dev/eslint-rules eslint@^9.0.0 eslint-plugin-svelte@^3.12.3 svelte@^5.38.10 svelte-eslint-parser@^1.3.2 typescript@^5.9.2

Supported File Types

This package provides the strictest ESLint rules for next type of files:

• javascript files **/*.js, **/*.cjs, **/*.mjs rules:
  • @eslint/js(Common JS rules)
  • @eslint-community/eslint-plugin-eslint-comments
  • @stylistic/eslint-plugin(No needed use prettier anymore)
  • eslint-plugin-check-file(Strict rules for files and folders naming)
  • eslint-plugin-import-x
  • eslint-plugin-jsdoc
  • eslint-plugin-n
  • eslint-plugin-perfectionist(Best sorting for everything in JS/TS)
  • eslint-plugin-prefer-arrow(No needed use function anymore)
  • eslint-plugin-promise
  • eslint-plugin-regexp
  • eslint-plugin-unicorn(🦄)
• json **/*.jsonc, **/*.json files(e.g. tsconfig.json, src/some-path/file.json) rules: eslint-plugin-jsonc
• markdown **/*.md files rules: @eslint/markdown
• ignores: common ignore rules for **/dist/**, **/node_modules/**
• package.json rules: eslint-plugin-package-json + json rules
• react **/*.jsx, **/*.tsx files rules + javascript:
  • eslint-plugin-jsx-a11y(Static AST checker for accessibility rules on JSX elements)
  • eslint-plugin-react-hooks eslint-plugin-react-perf
  • eslint-plugin-react
• svelte **/*.svelte files rules: eslint-plugin-svelte + javascript rules
• typescript **/*.cts, **/*.mts, **/*.ts files rules: typescript-eslint + javascript rules
• vitest **/*.spec.cts, **/*.spec.mts, **/*.spec.ts, **/*.test.cts, **/*.test.mts, **/*.test.ts files rules: @vitest/eslint-plugin
• vue **/*.vue files rules + javascript rules:
  • eslint-plugin-vue-scoped-css
  • eslint-plugin-vue
  • eslint-plugin-vuejs-accessibility(An eslint plugin for checking accessibility rules from within .vue files)

Usage

Basic Configuration

Create eslint.config.mjs in your project root:

import { configs } from '@libs-for-dev/eslint-rules'

export default [
  configs.ignores,
  configs.javascript,
  configs.json,
  configs.markdown,
  configs.packageJson,
]

TypeScript Project

import { configs } from '@libs-for-dev/eslint-rules'

export default [
  configs.ignores,
  configs.typescript,
  configs.json,
  configs.markdown,
  configs.packageJson,
]

Vue.js Project

import { configs } from '@libs-for-dev/eslint-rules'

export default [
  configs.ignores,
  configs.typescript, // if using TypeScript
  configs.vue,
  configs.json,
  configs.markdown,
  configs.packageJson,
]

Customization

import { configs } from '@libs-for-dev/eslint-rules'

export default [
  configs.typescript,
  configs.vue,
  {
    files: configs.vue.files,
    languageOptions: configs.vue.languageOptions,
    plugins: configs.vue.plugins,
    rules: {
      'vue/block-lang': ['error', { script: { lang: 'js' } }],
    },
  },
  {
    plugins: {
      ...configs.javascript.plugins,
    },
    rules: {
      'check-file/filename-naming-convention': [
        'error', { '**/*.vue': 'CAMEL_CASE' },
      ],
    },
  },
  {
    files: ['**/*.test.ts'],
    rules: {
      'max-lines-per-function': ['error', { max: 80 }],
    },
  },
  {
    files: ['/some/specific/folder/*.ts'],
    rules: {
      'max-lines': 'off',
    },
  }
]

ESLint Rules Overview

Code Quality Rules

• Error Prevention

  • no-unused-vars - Prevent unused variables
  • no-undef - Prevent usage of undeclared variables
  • no-console - Disallow console.log and similar methods
  • no-debugger - Disallow debugger statements

• Best Practices

  • prefer-arrow - Enforce using arrow functions
  • prefer-const - Require const declarations for variables that are never reassigned
  • no-var - Prevent usage of var
  • promise/catch-or-return - Enforce handling of Promises rejection

Style Rules

• Formatting

  • @stylistic/indent - Enforce consistent indentation
  • @stylistic/quotes - Enforce consistent quote style
  • @stylistic/semi - Enforce consistent semicolon usage
  • @stylistic/comma-dangle - Enforce consistent comma style

• Naming Conventions

  • check-file/filename-naming-convention - Enforce file naming conventions
  • check-file/folder-naming-convention - Enforce folder naming conventions

TypeScript Specific

• Type Safety
  • @typescript-eslint/strict-boolean-expressions
  • @typescript-eslint/no-explicit-any
  • @typescript-eslint/explicit-function-return-type
  • @typescript-eslint/explicit-member-accessibility

React Specific

• Hooks

  • react-hooks/rules-of-hooks - Enforce Rules of Hooks
  • react-hooks/exhaustive-deps - Verify dependencies array

• Accessibility

  • jsx-a11y/alt-text - Enforce alt text for images
  • jsx-a11y/click-events-have-key-events - Ensure keyboard accessibility

Vue Specific

• Template

  • vue/no-unused-components - Prevent unused components
  • vue/valid-template-root - Enforce valid template root
  • vue/multi-word-component-names - Enforce multi-word component names

• Accessibility

  • vuejs-accessibility/alt-text - Enforce alt text for images
  • vuejs-accessibility/click-events-have-key-events - Ensure keyboard accessibility

Testing (Vitest)

• Best Practices
  • vitest/expect-expect - Enforce expecting test results
  • vitest/no-disabled-tests - Disallow disabled tests
  • vitest/no-focused-tests - Disallow focused tests

Documentation

• JSDoc
  • jsdoc/require-jsdoc - Require JSDoc comments
  • jsdoc/require-param - Require parameter documentation
  • jsdoc/require-returns - Require return documentation

Import/Export

• Organization
  • import-x/order - Enforce import order
  • import-x/no-duplicates - Prevent duplicate imports
  • perfectionist/sort-imports - Sort import statements

Performance

• React

  • react-perf/jsx-no-new-object-as-prop - Prevent new objects in props
  • react-perf/jsx-no-new-array-as-prop - Prevent new arrays in props

• Vue

  • vue/no-async-in-computed-properties - Prevent async computed properties
  • vue/no-side-effects-in-computed-properties - Prevent side effects in computed

Regular Expressions

• Safety
  • regexp/no-empty-group - Disallow empty regex groups
  • regexp/no-useless-quantifier - Prevent useless quantifiers

Package.json

• Maintenance
  • package-json/sort-fields - Enforce consistent field ordering
  • package-json/valid-dependencies - Ensure valid dependencies