Agent skill · software engineering · affaan-m
bun-runtime
Bun as runtime, package manager, bundler, and test runner. When to choose Bun vs Node, migration notes, and Vercel support.
Why this skill is useful
Provides specific commands and migration patterns for using Bun that the AI wouldn't reliably generate on its own.
What it needs
Requires bun installed locally. About 3k tokens when loaded. Last updated 2026-08-06. 238,342 stars on the source repository.
What this skill does
Bun Runtime Bun is a fast all-in-one JavaScript runtime and toolkit: runtime, package manager, bundler, and test runner. When to Use Prefer Bun for: new JS/TS projects, scripts where install/run speed matters, Vercel deployments with Bun runtime, and when you want a single toolchain (run + install + test + build). Prefer Node for: maximum ecosystem compatibility, legacy tooling that assumes Node, or when a dependency has known Bun issues. Use when: adopting Bun, migrating from Node, writing or debugging Bun scripts/tests, or configuring Bun on Vercel or other platforms. How It Works Version baseline: guidance below targets Bun 1.4.x. Check the actual version with bun --version before relying on flag names, since CLI flags can change between releases. Runtime: Drop-in Node-compatible runtime, built on JavaScriptCore. As of Bun 1.4 the runtime itself is implemented in Rust (migrated from Zig). Not 100% Node-compatible — some native addons, less-common node: internal APIs, and packages that depend on Node-specific internals can still fail; verify before depending on it in production. Package manager: Bun includes a package manager; installation performance depends on the project, network conditions, and cache state. Lockfile is bun.lock (text) by default in current Bun; older versions used bun.lockb (binary) — Bun still reads that format for migration, but new projects should use bun.lock. Bundler: Built-in bundler and transpiler for apps and libraries. Test runner: Built-in bun test with a Jest-like API. Migration from Node: Replace node script.js with bun run script.js or bun script.js. Run bun install in place of npm install; most packages work. Use bun run for npm scripts; bun x for npx-style one-off runs. Node built-ins are supported; prefer Bun APIs where they exist for better performance. Package and workspace commands: bun add <pkg> / bun remove <pkg> / bun update [pkg] manage dependencies; bun outdated lists stale deps. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills affaan-m/bun-runtime--81a145