NestJS Usage Finder

A VS Code extension that displays usages and definitions of functions, classes, and objects on hover — scoped to NestJS module context. Inspired by JetBrains IntelliJ's usage finder.

Features

🎯 Module-Scoped Usage Finding

Unlike generic "Find All References", this extension understands NestJS's module architecture:

• Smart Scoping: Only shows usages within the same NestJS module and modules that import it
• No False Positives: Avoids showing irrelevant usages from unrelated modules with identically-named methods

🔍 Rich Hover Information

When you hover over any symbol:

• Definition: Clickable link to jump to the symbol's definition
• Symbol Type: Shows if it's a class, method, @Injectable, @Controller, or @Module
• Usages: Up to 5 inline usages with file paths and line previews
• "Show More": Button to open a QuickPick panel with all usages

⚡ Performance Optimized

Designed for large codebases:

• LRU Caching: Frequently accessed analysis results are cached
• Incremental Updates: File watcher only invalidates affected cache entries
• Lazy Initialization: Module graph is built on first usage
• Parallel Processing: Files are analyzed in parallel batches

Installation

From VS Code Marketplace

1. Open VS Code
2. Press Cmd+Shift+X (Mac) or Ctrl+Shift+X (Windows/Linux)
3. Search for "NestJS Usage Finder"
4. Click Install

From VSIX File

code --install-extension nestjs-usage-extension-0.0.1.vsix

Usage

1. Open a NestJS project in VS Code
2. Navigate to any TypeScript file (.ts)
3. Hover over a function, class, or variable name
4. View the definition and usages in the hover tooltip
5. Click any link to navigate to that location
6. For methods with many usages, click "Show all X usages" to open the QuickPick panel

Commands

Configuration

Requirements

• VS Code 1.85.0 or higher
• NestJS project with @Module() decorated classes
• TypeScript files (.ts)

How It Works

Module Detection

The extension parses all *.module.ts files and extracts:

@Module({
  imports: [OtherModule],
  controllers: [UserController],
  providers: [UserService],
  exports: [UserService]
})
export class UserModule {}

Scope Resolution

When you hover over a symbol in UserService:

1. Extension identifies UserService belongs to UserModule
2. Finds all modules that import UserModule
3. Searches for usages only in files within this scope
4. Returns scoped, relevant results

Architecture

src/
├── extension.ts           # Entry point, registers providers
├── types.ts               # TypeScript interfaces
├── analyzer/
│   ├── nestjsAnalyzer.ts  # Main facade coordinating all analysis
│   ├── moduleGraphBuilder.ts  # Parses @Module() decorators
│   ├── usageFinder.ts     # Finds usages with module scoping
│   └── symbolResolver.ts  # Resolves definitions
├── providers/
│   ├── hoverProvider.ts   # Hover tooltip rendering
│   └── definitionProvider.ts  # Go-to-definition
└── cache/
    ├── indexCache.ts      # LRU cache implementation
    └── fileWatcher.ts     # Incremental file watching

Development

Prerequisites

• Node.js 20 LTS
• pnpm 9+

Setup

# Clone the repository
git clone https://github.com/your-org/nestjs-usage-extension.git
cd nestjs-usage-extension

# Install dependencies
pnpm install

# Compile
pnpm run compile

# Run extension in development mode
# Press F5 in VS Code to launch Extension Development Host

Scripts

Testing

# Run all tests
pnpm test

# Run tests in watch mode
pnpm run test:watch

Debug

1. Open the project in VS Code
2. Press F5 to launch Extension Development Host
3. Open a NestJS project in the new window
4. Set breakpoints in dist/ files
5. View output in "NestJS Usage Finder" Output Channel

CI/CD

Continuous Integration

Every push and pull request triggers:

• Linting with ESLint
• Unit tests with Vitest
• Build verification
• VSIX package creation

Publishing

Required secrets:

• VSCE_PAT: Azure DevOps Personal Access Token with Marketplace permissions

Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/my-feature
3. Make your changes
4. Run tests: npm test
5. Commit: git commit -m 'Add my feature'
6. Push: git push origin feature/my-feature
7. Open a Pull Request

Troubleshooting

Extension not activating

• Ensure you have a .ts file open
• Check the "NestJS Usage Finder" Output Channel for errors

No usages found

• Verify your NestJS modules have @Module() decorators
• Check if nestjsUsage.enableModuleScoping is limiting scope too much
• Try disabling module scoping temporarily to see all usages

Slow performance

• Increase nestjsUsage.cacheSize for larger projects
• Exclude unnecessary folders in .gitignore

License

MIT License - see LICENSE for details.

Acknowledgments

• Inspired by JetBrains IntelliJ IDEA's usage finder
• Built with VS Code Extension API
• Uses TypeScript Compiler API for AST parsing