Bun Skill Reference

Product Summary

Bun is a unified JavaScript runtime, package manager, bundler, and test runner written in Zig. It replaces Node.js, npm, esbuild, and Jest with a single fast binary. Key files: bunfig.toml (configuration), bun.lock (lockfile), package.json (project metadata). Primary commands: bun run, bun install, bun build, bun test. Bun is 4x faster than Node.js on startup and 25x faster than npm for installations. Visit https://bun.com/docs for comprehensive documentation.

When to Use

Use Bun when:

• Running scripts: Execute TypeScript/JavaScript files directly without compilation steps (bun run file.ts)
• Managing dependencies: Install, add, remove, or update packages faster than npm/yarn/pnpm (bun install, bun add)
• Bundling code: Build JavaScript/TypeScript for browser or server targets with bun build
• Testing: Run Jest-compatible tests with built-in test runner (bun test)
• Building full-stack apps: Bundle server and client code together into single executables
• Monorepo workflows: Use workspaces and filtering to manage multiple packages
• Replacing Node.js: Run any Node.js-compatible code with better performance

Do not use Bun for: type checking (use tsc separately), generating type declarations, or projects requiring exact Node.js compatibility for native modules.