Dead Code Detector

An efficient dead code detection tool designed for Vue 2/3 and React projects, helping identify and clean up unused code, exports, and components. Save time and reduce bundle size by eliminating code that's no longer needed.

✨ Key Features

• Comprehensive Detection: Unused exports, components, and utility files
• Multi-framework Support: Vue 2/3 (including <script setup>), React, TypeScript, JSX/TSX
• Dual Detection Modes: AST (accurate) and regex (compatible with legacy projects)
• Smart Auto-fix: Group export partial removal, multi-line export handling, error recovery
• Configuration Flexibility: .deadcoderc.json, .deadcoderc.js, and deadcode.config.js
• Path Alias Support: Auto-detects and resolves path aliases from project config
• Test File Awareness: Tracks imports from test files to avoid false positives
• LRU Cache: Memory-efficient caching with automatic eviction (v1.1.0)
• Incremental Analysis: File-based cache for faster re-runs with optimized dependency graph
• Backup System: Creates automatic backups before making changes
• Verbose Mode: Detailed progress and analysis information

🚀 Quick Start

# Install globally (recommended)
npm install -g @is_adou/dead-code-detector

# Run detection in your project
cd your-project
dead-code

# Auto-fix unused code
dead-code --fix

# Local installation
npm install @is_adou/dead-code-detector --save-dev

# Run with npx
npx dead-code

# Or add to package.json scripts
# {
#   "scripts": {
#     "dead-code": "dead-code"
#   }
# }
npm run dead-code

🛠️ Usage

Command Line

# Basic detection
dead-code

# Specify directory and mode
dead-code --src ./src --mode ast

# Auto-fix with preview
dead-code --fix --dry-run

# Auto-fix with confirmation
dead-code --fix --confirm

Configuration

Create .deadcoderc.json in your project root:

{
  "srcDir": "./src",
  "extensions": [".js", ".vue", ".jsx", ".ts", ".tsx"],
  "ignoreDirs": ["node_modules", "dist", ".git"],
  "mode": "ast",
  "cache": true,
  "cacheDir": ".dead-code-cache"
}

Incremental Analysis

Speed up re-runs by analyzing only changed files:

# Incremental analysis (auto-detect main/master branch)
dead-code --incremental

# Specify base branch
dead-code --incremental --base-branch develop

🔍 Detection Modes

AST Mode (Default)

Recommended for most projects

• Uses Babel AST parsing for highly accurate detection
• Supports multi-line exports, TypeScript types, and Vue <script setup>
• Better handling of complex export/import patterns

Regex Mode

For legacy projects or performance-critical scenarios

• Uses traditional regular expressions for faster scanning
• Less accurate but works with older codebases
• Limited support for complex syntax features

🛠️ Auto-fix

# Preview changes
dead-code --fix --dry-run

# Fix with confirmation
dead-code --fix --confirm

# Fix directly (use with caution!)
dead-code --fix

Safety Measures:

1. Always run without --fix first to preview
2. Use --dry-run to see what would be deleted
3. Use --confirm for interactive confirmation
4. Check backup/ directory if needed

📚 Advanced Usage

# Filter by extensions
dead-code --ext .js,.ts,.tsx

# Ignore directories
dead-code --ignore node_modules,dist,.git,coverage

# Verbose output
dead-code --verbose

# Custom source directory
dead-code --src ./src/components

# Combine options
dead-code --src ./src --mode ast --ext .js,.vue,.tsx --ignore node_modules,dist --verbose

📝 Configuration Examples

{
  "srcDir": "./src",
  "extensions": [".js", ".vue", ".ts"],
  "ignoreDirs": ["node_modules", "dist"],
  "mode": "ast"
}

{
  "srcDir": "./src",
  "extensions": [".js", ".jsx", ".ts", ".tsx"],
  "ignoreDirs": ["node_modules", "dist", "build"],
  "mode": "ast"
}

{
  "srcDir": "./src",
  "extensions": [".js"],
  "ignoreDirs": ["node_modules", "dist"],
  "mode": "regex"
}

🛠️ Troubleshooting

Common Issues

Q: Why are some exports not detected?

Possible reasons: dynamically imported, imported as side effect, used in test files, or path alias resolution failed.

Q: Why are components marked as unused?

Possible reasons: different naming convention (PascalCase vs kebab-case), used in template but not imported in script, or globally registered.

Q: What if auto-fix deleted wrong code?

Restore from backup/ directory. The tool creates automatic backups before making changes.

Q: Detection is slow for large projects?

1. Use AST mode (default) - it's faster for large projects
2. Add large directories to ignore list with --ignore
3. Limit file extensions with --ext

Error Messages

📖 API Documentation

For detailed API documentation, see API.md.

const { detect } = require('@is_adou/dead-code-detector');

const result = await detect({ srcDir: './src' });
console.log('Unused exports:', result.results.unusedExports);

🔄 Migration Guide

Migrating from other tools? See MIGRATION.md for:

• Migration from ts-prune, unused, webpack-deadcode-plugin
• Version upgrade instructions
• Configuration migration examples

🤝 Contributing

See CONTRIBUTING.md for guidelines.

📄 Changelog

See CHANGELOG.md for version history.

🌍 Languages

• English
• 中文

📝 License

MIT License - see LICENSE for details.

🙏 Acknowledgments

• Built with Babel for AST parsing
• Inspired by various dead code detection tools

Happy coding! 🎉