Bun vs Node.js

Understanding the differences between Bun and Node.js helps you leverage Bun's strengths while maintaining compatibility with the Node.js ecosystem.

Key Differences

Feature	Bun	Node.js
Engine	JavaScriptCore (Safari)	V8 (Chrome)
Language	Written in Zig	Written in C++
TypeScript	Native support	Requires transpilation
Package Manager	Built-in (bun install)	npm/yarn/pnpm
Bundler	Built-in	Webpack/Rollup/etc.
Test Runner	Built-in (bun test)	Jest/Vitest/etc.

Speed Comparison

Bun is significantly faster in many scenarios:

Node.js Compatibility

Bun aims for high compatibility with Node.js. Most Node.js code works in Bun:

Bun-Specific Features

Bun adds features not available in Node.js:

Migration Tips

When migrating from Node.js to Bun:

Exercise: Bun Detection

Write code that detects whether it's running in Bun or Node.js:

Exercise: Cross-Runtime Utility

Create a function that works in both Bun and Node.js: