# Node.js & JavaScript Skill

## Installed Versions
- Node.js 20.x
- npm 10.x
- Claude Code CLI

## Common Commands

### Project Initialization
```bash
npm init -y                    # Initialize package.json
npm install express            # Install dependency
npm install -D nodemon        # Install dev dependency
npm install --save-exact       # Install exact version
```

### Development
```bash
npm start                       # Start app
npm run dev                    # Start with hot reload
npm test                        # Run tests
npm run build                   # Build for production
npm outdated                    # Check for updates
npm update                      # Update dependencies
```

### Docker for Node
```bash
# Basic Dockerfile
FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
EXPOSE 3000
CMD ["npm", "start"]
```

## Project Templates

### Express API
```javascript
const express = require('express');
const app = express();
const port = 3000;

app.use(express.json());
app.get('/', (req, res) => res.send('Hello'));
app.listen(port, () => console.log(`Server on ${port}`));
```

### Fast Setup
```bash
npx create-next-app myapp        # Next.js
npx create-react-app myapp       # React
npx create-vue-app myapp         # Vue
```

## Best Practices
- Use `npm ci` instead of `npm install` in CI/CD
- Use `package-lock.json` for reproducible builds
- Define scripts in package.json for common tasks
- Use environment variables with `dotenv`