In modern JavaScript and TypeScript projects, keeping your codebase clean and efficient is a constant challenge. Unused files, dead code, and unnecessary dependencies can slow down your build times, increase bundle sizes, and make maintenance harder. That’s where Knip comes in—a powerful tool designed to analyze your project and detect unused exports, files, and dependencies.

Whether you’re working with Next.js, Vite, NestJS, or a monorepo, Knip helps developers streamline their code, reduce technical debt, and optimize performance.

Why Should You Use Knip?

  • Removes Dead Code – Knip scans your project to find unused exports, helping you eliminate redundant functions, variables, and components.
  • Detects Unused Dependencies – It identifies dependencies in your package.json that are installed but never actually used in your project.
  • Works with Monorepos – Knip is designed to handle large projects and monorepos, making it an excellent choice for enterprise applications.
  • Supports Modern Frameworks – It works seamlessly with popular frameworks like Next.js, Vite, NestJS, and more.
  • Enhances Performance & Maintainability – Keeping your codebase clean ensures faster build times and easier maintenance.

Installing Knip

Getting started with Knip is simple. You can install it globally or as a dev dependency in your project:

# Install globally
npm install -g knip
# Or install as a dev dependency
npm install --save-dev knip

Once installed, you can run Knip from the command line.

Running Knip on Your Project

To scan your project for unused files and dependencies, simply run:

npx knip

Knip will analyze your project and generate a detailed report, showing unused files, exports, and dependencies.
Example output:

Unused dependencies:
- lodash
- moment
Unused files:
- src/utils/oldHelper.ts
- src/components/DeprecatedComponent.tsx

This report helps you clean up your codebase quickly and efficiently.

Configuring Knip

Knip is highly configurable. You can add a knip.json or knip.config.js file to fine-tune its behavior.
Example knip.config.js:

module.exports = {
  entry: ['src/index.ts'], // Define entry points
  ignore: ['src/legacy/**'], // Ignore specific folders
  ignoreDependencies: ['eslint'], // Ignore certain dependencies
};

This allows you to tailor Knip to your project’s needs.

Integrating Knip into CI/CD

To ensure your code stays clean, you can integrate Knip into your CI/CD pipeline. Add it as a step in your GitHub Actions or GitLab CI/CD pipeline.
Example GitHub Actions workflow:

name: Check for Unused Code
on: [push, pull_request]
jobs:
  knip-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: 18
      - run: npm install
      - run: npx knip

This ensures that unused files and dependencies are detected before merging code into your main branch.

Knip vs. Other Tools

Feature Knip depcheck ts-prune
Detects unused dependencies ✅ ✅ ❌
Detects unused exports ✅ ❌ ✅
Supports monorepos ✅ ❌ ❌
Works with TypeScript ✅ ✅ ✅
Customizable config ✅ ❌ ❌

Summary:

Knip is a must-have tool for JavaScript and TypeScript developers who want to keep their projects clean, efficient, and easy to maintain. By detecting unused code and dependencies, it helps optimize performance, reduce bundle sizes, and improve overall code quality.

If you haven’t tried Knip yet, now is the perfect time to integrate it into your workflow and take your project maintenance to the next level!