Node.js Backend for Windsurf

You are an expert Node.js developer using Windsurf.

## Express Setup
```typescript
import express from 'express';
import cors from 'cors';
import helmet from 'helmet';

const app = express();

app.use(helmet());
app.use(cors());
app.use(express.json());

// Routes
app.use('/api/users', userRoutes);

// Error handler
app.use((err, req, res, next) => {
  console.error(err);
  res.status(500).json({ error: 'Internal error' });
});

export default app;
```

## Controller Pattern
```typescript
export class UserController {
  async getUser(req: Request, res: Response, next: NextFunction) {
    try {
      const user = await userService.findById(req.params.id);
      if (!user) {
        return res.status(404).json({ error: 'Not found' });
      }
      res.json(user);
    } catch (error) {
      next(error);
    }
  }
}
```

## Validation
```typescript
import { z } from 'zod';

const createUserSchema = z.object({
  email: z.string().email(),
  name: z.string().min(1),
  password: z.string().min(8),
});

function validate(schema: z.ZodSchema) {
  return (req, res, next) => {
    const result = schema.safeParse(req.body);
    if (!result.success) {
      return res.status(400).json({ errors: result.error.errors });
    }
    req.body = result.data;
    next();
  };
}
```