Bun is a fast all-in-one JavaScript runtime. After using Bun in production, here’s how to leverage it effectively.

What is Bun?

Bun provides:

  • JavaScript runtime - Like Node.js
  • Bundler - Build tool
  • Test runner - Testing framework
  • Package manager - npm alternative

Installation

# Install Bun
curl -fsSL https://bun.sh/install | bash

# Verify
bun --version

Basic Usage

Run Scripts

# Run JavaScript file
bun run index.js

# Run TypeScript directly
bun run index.ts

Package Management

# Install package
bun install express

# Add dependency
bun add express

# Remove dependency
bun remove express

API Compatibility

Node.js APIs

// File system
import { readFile } from 'fs/promises';
const data = await readFile('file.txt');

// HTTP server
import { createServer } from 'http';
const server = createServer((req, res) => {
    res.end('Hello from Bun!');
});
server.listen(3000);

Web APIs

// Fetch API
const response = await fetch('https://api.example.com/data');
const data = await response.json();

// WebSocket
const ws = new WebSocket('ws://localhost:8080');

Performance

Startup Time

# Node.js
time node index.js
# ~50ms

# Bun
time bun run index.js
# ~5ms

HTTP Server

// Bun HTTP server
export default {
    port: 3000,
    fetch(request) {
        return new Response('Hello from Bun!');
    }
};

Best Practices

  1. Use for new projects - Better performance
  2. Test compatibility - Verify Node.js APIs
  3. Leverage speed - Fast startup
  4. Use bundler - Built-in bundling
  5. TypeScript support - Native TS
  6. Monitor - Track performance
  7. Stay updated - New features
  8. Document - Team knowledge

Conclusion

Bun enables:

  • Fast runtime
  • All-in-one tooling
  • Better performance
  • Modern features

Use Bun for new projects or performance-critical applications. The runtime shown here provides significant performance improvements.

Bun JavaScript runtime from January 2023, covering installation, usage, and performance.