Node.js Linters Guide¶

This guide covers comprehensive support for JavaScript and TypeScript linting with aider-lint-fixer, including ESLint, Prettier, and project-specific configurations.

Supported Node.js Linters¶

ESLint¶

Version Support: 8.x, 9.x
Extensions: .js, .jsx, .ts, .tsx, .mjs, .cjs
Configuration Detection: Automatic detection of .eslintrc.* files
TypeScript Support: Full integration with @typescript-eslint

Prettier¶

Version Support: 2.x, 3.x
Integration: Works alongside ESLint for formatting
Configuration: Auto-detects .prettierrc.* files

JSHint¶

Version Support: 2.x
Legacy Support: For older JavaScript projects
Configuration: .jshintrc file detection

Quick Start¶

1. Project Detection¶

aider-lint-fixer automatically detects Node.js projects by looking for:

# Package files
package.json
package-lock.json
yarn.lock

# TypeScript configuration
tsconfig.json

# ESLint configuration
.eslintrc.js
.eslintrc.json
.eslintrc.yml
eslint.config.js

# Prettier configuration
.prettierrc
.prettierrc.json
prettier.config.js

2. Basic Usage¶

# Automatic detection and fixing
aider-lint-fixer ./my-node-project

# Specific linter
aider-lint-fixer --linter eslint ./src

# TypeScript project
aider-lint-fixer --profile strict ./typescript-app

ESLint Integration¶

Automatic Configuration Detection¶

aider-lint-fixer detects and respects your existing ESLint setup:

// .eslintrc.js - Automatically detected
module.exports = {
  extends: ['@typescript-eslint/recommended'],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  rules: {
    'prefer-const': 'error',
    'no-unused-vars': 'warn'
  }
};

Supported ESLint Rules¶

Common rules with high fix success rates:

Rule	Fix Rate	Complexity
`semi`	98%	Trivial
`quotes`	95%	Trivial
`indent`	92%	Simple
`no-unused-vars`	88%	Simple
`prefer-const`	94%	Simple
`no-trailing-spaces`	99%	Trivial
`max-len`	75%	Moderate

TypeScript-Specific Rules¶

Enhanced support for TypeScript projects:

// Example fixes for common TypeScript issues
// @typescript-eslint/no-unused-vars
const unusedVar = 'remove me'; // ❌ Removed automatically

// @typescript-eslint/prefer-const
let unchangedValue = 'hello'; // ❌ Changed to const

// @typescript-eslint/explicit-function-return-type
function getValue() { // ❌ Adds return type
  return 42;
}

Project Profiles¶

Basic Profile (Development)¶

Optimized for development environments:

aider-lint-fixer --profile basic ./src

Includes: - Essential syntax errors - Code style issues - Basic TypeScript errors - Performance suggestions

Excludes: - Strict type checking - Complex refactoring rules - Deprecated APIs (warnings only)

Strict Profile (Production)¶

Comprehensive checking for production code:

aider-lint-fixer --profile strict ./src

Includes: - All basic profile rules - Strict TypeScript checking - Security vulnerability detection - Performance optimizations - Code complexity analysis

Configuration Examples¶

1. React Project¶

// package.json
{
  "scripts": {
    "lint": "aider-lint-fixer --profile basic ./src",
    "lint:fix": "aider-lint-fixer --auto-fix ./src",
    "lint:strict": "aider-lint-fixer --profile strict ./src"
  },
  "devDependencies": {
    "@typescript-eslint/eslint-plugin": "^6.0.0",
    "@typescript-eslint/parser": "^6.0.0",
    "eslint": "^8.45.0"
  }
}

2. Node.js API Project¶

// .eslintrc.js
module.exports = {
  env: {
    node: true,
    es2022: true
  },
  extends: [
    'eslint:recommended',
    '@typescript-eslint/recommended'
  ],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  rules: {
    'no-console': 'warn', // Allow console in development
    'prefer-const': 'error'
  }
};

3. Monorepo Setup¶

# Root level - lint all packages
aider-lint-fixer --recursive ./packages

# Specific package
aider-lint-fixer ./packages/frontend

# Different profiles per package
aider-lint-fixer --profile basic ./packages/frontend
aider-lint-fixer --profile strict ./packages/api

Advanced Features¶

1. Custom Rule Configuration¶

Override fixability for specific rules:

// .aider-lint-fixer.json
{
  "linters": {
    "eslint": {
      "force_fix_rules": [
        "semi",
        "quotes",
        "prefer-const"
      ],
      "skip_rules": [
        "no-any" // Too complex for auto-fix
      ]
    }
  }
}

2. TypeScript Integration¶

Enhanced TypeScript support:

# Respect tsconfig.json settings
aider-lint-fixer --typescript-project ./tsconfig.json ./src

# Multiple TypeScript projects
aider-lint-fixer \
  --typescript-project ./frontend/tsconfig.json ./frontend/src \
  --typescript-project ./backend/tsconfig.json ./backend/src

3. Performance Optimization¶

For large Node.js projects:

# Parallel processing
aider-lint-fixer --parallel 4 ./large-project

# Incremental fixing (only changed files)
aider-lint-fixer --incremental ./src

# Focus on specific file types
aider-lint-fixer --include "*.ts,*.tsx" ./src

Common Use Cases¶

1. Legacy JavaScript Migration¶

Converting old JavaScript to modern standards:

# Step 1: Basic cleanup
aider-lint-fixer --profile basic ./legacy-js

# Step 2: Modern JavaScript features
aider-lint-fixer --profile strict --rules "prefer-const,arrow-functions" ./legacy-js

# Step 3: TypeScript migration prep
aider-lint-fixer --typescript-prep ./legacy-js

2. CI/CD Integration¶

# .github/workflows/lint.yml
name: Lint Check
on: [push, pull_request]
jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: '18'
      - run: npm install
      - run: npx aider-lint-fixer --strict --dry-run ./src

3. Pre-commit Integration¶

# .pre-commit-config.yaml
repos:
  - repo: local
    hooks:
      - id: aider-lint-fixer
        name: Aider Lint Fixer
        entry: aider-lint-fixer
        language: system
        files: '\.(js|jsx|ts|tsx)$'
        args: ['--auto-fix']

Troubleshooting¶

Common Issues¶

1. ESLint Configuration Not Found¶

# Check configuration detection
aider-lint-fixer --debug --dry-run ./src

# Manually specify configuration
aider-lint-fixer --eslint-config ./.eslintrc.js ./src

2. TypeScript Parsing Errors¶

# Verify TypeScript setup
npx tsc --noEmit

# Use TypeScript-aware mode
aider-lint-fixer --typescript ./src

3. Large Project Performance¶

# Use incremental mode
aider-lint-fixer --incremental ./large-project

# Exclude node_modules and build directories
aider-lint-fixer --exclude "**/node_modules/**,**/dist/**" ./project

Performance Tips¶

Use .eslintignore: Exclude unnecessary files
Incremental mode: Only process changed files
Parallel processing: Use --parallel for large projects
Targeted fixing: Focus on specific rule categories

Rule Categories¶

High Success Rate (>90%)¶

Formatting rules (semi, quotes, indent)
Simple style rules (prefer-const, arrow-spacing)
Basic cleanup (no-trailing-spaces, no-multiple-empty-lines)

Medium Success Rate (70-90%)¶

Variable usage (no-unused-vars, no-undef)
Import/export organization
Basic TypeScript annotations

Complex Rules (<70%)¶

Logic changes (no-implicit-any, strict-boolean-expressions)
Architectural refactoring
Complex type inference

Integration with Other Tools¶

Prettier Integration¶

# Run Prettier first, then ESLint
prettier --write ./src && aider-lint-fixer ./src

# Or use combined profile
aider-lint-fixer --profile prettier-eslint ./src

Webpack/Vite Integration¶

Works seamlessly with build tools:

// webpack.config.js - No special configuration needed
// Vite.config.js - Standard ESLint plugin integration