AgentSkillsCN

bun

Bun JavaScript/TypeScript运行时及一体化工具集，囊括运行时、包管理器、打包工具、测试运行器、HTTP服务器、WebSocket、SQLite、S3、Redis、文件I/O、Shell脚本、FFI、Markdown解析器等核心功能。关键词：bun、bunx、bun install、bun run、bun test、bun build、Bun.serve、Bun.file、bun:sqlite、Bun.markdown。

SKILL.md
--- frontmatter
name: bun
description: "Bun JavaScript/TypeScript runtime and all-in-one toolkit. Covers runtime, package manager, bundler, test runner, HTTP server, WebSockets, SQLite, S3, Redis, file I/O, shell scripting, FFI, Markdown parser. Keywords: bun, bunx, bun install, bun run, bun test, bun build, Bun.serve, Bun.file, bun:sqlite, Bun.markdown."
version: "1.3.8"
release_date: "2026-01-29"

Bun

All-in-one JavaScript/TypeScript toolkit: runtime, package manager, test runner, bundler.

Quick Navigation

TopicReference
Package Managerreferences/package-manager.md
Project Setupreferences/project-scaffolding.md
Developmentreferences/development.md
Module Systemreferences/module-system.md
TypeScript & JSXreferences/typescript-jsx.md
Configurationreferences/bunfig.md
HTTP Serverreferences/http-server.md
WebSocketsreferences/websockets.md
File I/Oreferences/file-io.md
SQLitereferences/sqlite.md
S3 Storagereferences/s3.md
Redisreferences/redis.md
Low-Level Networkreferences/networking-low-level.md
Fetch APIreferences/fetch.md
Shell Scriptsreferences/shell.md
Spawn Processreferences/spawn.md
Workersreferences/workers.md
Native FFIreferences/native-interop.md
C/C++ Compilereferences/cc.md
Transpilerreferences/transpiler.md
Pluginsreferences/plugins.md
FS Routerreferences/file-system-router.md
Environment Varsreferences/env.md
Utilitiesreferences/utilities.md
Node.js Compatreferences/nodejs-compat.md

When to Use Bun

  • •Running TypeScript/JSX without build step
  • •Fast HTTP server with native routing
  • •SQLite database (embedded, no deps)
  • •WebSocket server/client
  • •S3-compatible storage (AWS, R2, MinIO)
  • •Redis caching/pub-sub
  • •Cross-platform shell scripts
  • •Markdown parsing (v1.3.8+)
  • •Native library calls via FFI

Core Advantages

  • •4x faster startup than Node.js
  • •Native TypeScript/JSX — no tsconfig needed
  • •ESM + CommonJS — both work seamlessly
  • •Web APIs built-in — fetch, WebSocket, etc.
  • •30x faster installs than npm

Quick Start

bash
# Run TypeScript directly
bun run index.ts

# Install packages
bun install

# Run package.json script
bun run dev

# Execute package binary
bunx cowsay "Hello"

# Run tests
bun test

# Build for production
bun build ./index.ts --outdir ./dist

# Bundle analysis for LLMs (v1.3.8+)
bun build ./index.ts --metafile-md --outdir ./dist

Critical Rules

Don'tDo
http.createServer()Bun.serve()
fs.readFileSync()Bun.file().text()
better-sqlite3bun:sqlite
child_process.exec()Bun.$ or Bun.spawn()
dotenvBuilt-in .env support

Essential Recipes

HTTP Server

ts
Bun.serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);
    if (url.pathname === "/api/data") {
      return Response.json({ ok: true });
    }
    return new Response("Not Found", { status: 404 });
  },
});

File Operations

ts
// Read
const content = await Bun.file("data.txt").text();

// Write
await Bun.write("output.txt", "Hello World");

// JSON
const config = await Bun.file("config.json").json();

SQLite

ts
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 insert = db.prepare("INSERT INTO users (name) VALUES (?)");
insert.run("Alice");

const users = db.query("SELECT * FROM users").all();

WebSocket Server

ts
Bun.serve({
  fetch(req, server) {
    if (server.upgrade(req)) return;
    return new Response("Upgrade failed", { status: 400 });
  },
  websocket: {
    message(ws, message) {
      ws.send(`Echo: ${message}`);
    },
  },
});

Shell Commands

ts
import { $ } from "bun";

// Simple command
const files = await $`ls -la`.text();

// With variables (auto-escaped)
const name = "my file.txt";
await $`cat ${name}`;

// Piping
await $`cat data.csv | grep "pattern" | wc -l`;

S3 Storage

ts
import { s3 } from "bun";

// Upload
await s3.file("uploads/doc.pdf").write(data);

// Download
const content = await s3.file("uploads/doc.pdf").text();

// Presigned URL
const url = s3.presign("uploads/doc.pdf", { expiresIn: 3600 });

Redis

ts
import { redis } from "bun";

await redis.set("key", "value");
const value = await redis.get("key");
await redis.expire("key", 3600);

Testing

ts
import { expect, test, describe } from "bun:test";

describe("math", () => {
  test("2 + 2 = 4", () => {
    expect(2 + 2).toBe(4);
  });
});

Configuration (bunfig.toml)

toml
[run]
watch = true

[install]
registry = "https://registry.npmjs.org"

[test]
coverage = true

Environment Variables

bash
# .env files loaded automatically
DATABASE_URL=postgres://localhost/mydb
ts
// Access
Bun.env.DATABASE_URL
process.env.DATABASE_URL
import.meta.env.DATABASE_URL

Links