⚡ Bun Development

Fast, modern JavaScript/TypeScript development with the Bun runtime, inspired by oven-sh/bun.

When to Use This Skill

Use this skill when:

• Starting new JS/TS projects with Bun
• Migrating from Node.js to Bun
• Optimizing development speed
• Using Bun's built-in tools (bundler, test runner)
• Troubleshooting Bun-specific issues

1. Getting Started

1.1 Installation

# macOS / Linux
curl -fsSL https://bun.sh/install | bash

# Windows
powershell -c "irm bun.sh/install.ps1 | iex"

# Homebrew
brew tap oven-sh/bun
brew install bun

# npm (if needed)
npm install -g bun

# Upgrade
bun upgrade

1.2 Why Bun?

2. Project Setup

2.1 Create New Project

# Initialize project
bun init

# Creates:
# ├── package.json
# ├── tsconfig.json
# ├── index.ts
# └── README.md

# With specific template
bun create <template> <project-name>

# Examples
bun create react my-app        # React app
bun create next my-app         # Next.js app
bun create vite my-app         # Vite app
bun create elysia my-api       # Elysia API

2.2 package.json

{
  "name": "my-bun-project",
  "version": "1.0.0",
  "module": "index.ts",
  "type": "module",
  "scripts": {
    "dev": "bun run --watch index.ts",
    "start": "bun run index.ts",
    "test": "bun test",
    "build": "bun build ./index.ts --outdir ./dist",
    "lint": "bunx eslint ."
  },
  "devDependencies": {
    "@types/bun": "latest"
  },
  "peerDependencies": {
    "typescript": "^5.0.0"
  }
}

2.3 tsconfig.json (Bun-optimized)

{
  "compilerOptions": {
    "lib": ["ESNext"],
    "module": "esnext",
    "target": "esnext",
    "moduleResolution": "bundler",
    "moduleDetection": "force",
    "allowImportingTsExtensions": true,
    "noEmit": true,
    "composite": true,
    "strict": true,
    "downlevelIteration": true,
    "skipLibCheck": true,
    "jsx": "react-jsx",
    "allowSyntheticDefaultImports": true,
    "forceConsistentCasingInFileNames": true,
    "allowJs": true,
    "types": ["bun-types"]
  }
}

3. Package Management

3.1 Installing Packages

# Install from package.json
bun install              # or 'bun i'

# Add dependencies
bun add express          # Regular dependency
bun add -d typescript    # Dev dependency
bun add -D @types/node   # Dev dependency (alias)
bun add --optional pkg   # Optional dependency

# From specific registry
bun add lodash --registry https://registry.npmmirror.com

# Install specific version
bun add [email protected]
bun add react@latest
bun add react@next

# From git
bun add github:user/repo
bun add git+https://github.com/user/repo.git

3.2 Removing & Updating

# Remove package
bun remove lodash

# Update packages
bun update              # Update all
bun update lodash       # Update specific
bun update --latest     # Update to latest (ignore ranges)

# Check outdated
bun outdated

3.3 bunx (npx equivalent)

# Execute package binaries
bunx prettier --write .
bunx tsc --init
bunx create-react-app my-app

# With specific version
bunx -p [email protected] tsc --version

# Run without installing
bunx cowsay "Hello from Bun!"

3.4 Lockfile

# bun.lockb is a binary lockfile (faster parsing)
# To generate text lockfile for debugging:
bun install --yarn    # Creates yarn.lock

# Trust existing lockfile
bun install --frozen-lockfile

4. Running Code

4.1 Basic Execution

# Run TypeScript directly (no build step!)
bun run index.ts

# Run JavaScript
bun run index.js

# Run with arguments
bun run server.ts --port 3000

# Run package.json script
bun run dev
bun run build

# Short form (for scripts)
bun dev
bun build

4.2 Watch Mode

# Auto-restart on file changes
bun --watch run index.ts

# With hot reloading
bun --hot run server.ts

4.3 Environment Variables

// .env file is loaded automatically!

// Access environment variables
const apiKey = Bun.env.API_KEY;
const port = Bun.env.PORT ?? "3000";

// Or use process.env (Node.js compatible)
const dbUrl = process.env.DATABASE_URL;

# Run with specific env file
bun --env-file=.env.production run index.ts

5. Built-in APIs

5.1 File System (Bun.file)

// Read file
const file = Bun.file("./data.json");
const text = await file.text();
const json = await file.json();
const buffer = await file.arrayBuffer();

// File info
console.log(file.size); // bytes
console.log(file.type); // MIME type

// Write file
await Bun.write("./output.txt", "Hello, Bun!");
await Bun.write("./data.json", JSON.stringify({ foo: "bar" }));

// Stream large files
const reader = file.stream()
how to use bun-development
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use bun-development on Cursor
AI-first code editor with Composer
1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add bun-development
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/davila7/claude-code-templates --skill bun-developmentcopy
The skills CLI fetches bun-development from GitHub repository davila7/claude-code-templates and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
│   • Antigravity
│   • Cline
│   • Codex
│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/bun-development
Reload or restart Cursor to activate bun-development. Access the skill through slash commands (e.g., /bun-development) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?