Bun
> All-in-one JavaScript runtime — bundler, transpiler, package manager, test runner.
Best use case
Bun is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
> All-in-one JavaScript runtime — bundler, transpiler, package manager, test runner.
Teams using Bun should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/bun/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How Bun Compares
| Feature / Agent | Bun | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
> All-in-one JavaScript runtime — bundler, transpiler, package manager, test runner.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Bun
> All-in-one JavaScript runtime — bundler, transpiler, package manager, test runner.
## When to Use
- Fast package installs (replaces npm/yarn/pnpm)
- Running TypeScript directly without build step
- Bundling for production
- Fast test runner (replaces Jest/Vitest for simple cases)
- SQLite built-in, HTTP server, file I/O
## Core Patterns
### Package Management
```bash
bun install # Install deps (faster than npm)
bun add zod hono # Add packages
bun add -d vitest # Add dev dependency
bun remove lodash # Remove package
bun update # Update all deps
bunx create-next-app # npx equivalent
```
### Runtime
```typescript
// Run any .ts/.tsx/.js file directly
// $ bun run server.ts
// Built-in HTTP server (faster than Node http)
Bun.serve({
port: 3000,
fetch(req) {
const url = new URL(req.url);
if (url.pathname === "/api/health") {
return Response.json({ status: "ok" });
}
return new Response("Not found", { status: 404 });
},
});
// Built-in SQLite
import { Database } from "bun:sqlite";
const db = new Database("app.db");
db.run("CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT)");
const users = db.query("SELECT * FROM users").all();
// File I/O (faster than fs)
const file = Bun.file("data.json");
const data = await file.json();
await Bun.write("output.txt", "hello");
// Shell (bun sh)
import { $ } from "bun";
const result = await $`ls -la`.text();
```
### Testing
```typescript
// Uses Jest-compatible API
import { test, expect, describe } from "bun:test";
describe("math", () => {
test("adds", () => {
expect(1 + 1).toBe(2);
});
});
// Run: bun test
```
### Key Conventions
- **bun.lockb**: Binary lockfile (faster parsing than JSON)
- **Workspaces**: Same as npm workspaces in package.json
- **Environment**: `Bun.env.DATABASE_URL` (auto-loads .env)
- **Macros**: `import { thing } from "./data" with { type: "macro" }` — runs at bundle time
- **Node compat**: 99%+ Node.js API compatibility, drop-in replacementRelated Skills
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