feat: add Express API base structure

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/app.ts

@@ -0,0 +1,31 @@
+import express from 'express';
+import cors from 'cors';
+import helmet from 'helmet';
+import { env } from './config/env.js';
+import { errorMiddleware } from './middlewares/error.middleware.js';
+
+const app = express();
+
+// Security
+app.use(helmet());
+app.use(cors({
+  origin: env.CORS_ORIGIN,
+  credentials: true,
+}));
+
+// Body parsing
+app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
+
+// Health check
+app.get('/health', (req, res) => {
+  res.json({ status: 'ok', timestamp: new Date().toISOString() });
+});
+
+// API Routes (to be added)
+// app.use('/api/auth', authRoutes);
+
+// Error handling
+app.use(errorMiddleware);
+
+export { app };

apps/api/src/config/env.ts

@@ -0,0 +1,20 @@
+import { z } from 'zod';
+
+const envSchema = z.object({
+  NODE_ENV: z.enum(['development', 'production', 'test']).default('development'),
+  PORT: z.string().default('4000'),
+  DATABASE_URL: z.string(),
+  JWT_SECRET: z.string().min(32),
+  JWT_EXPIRES_IN: z.string().default('15m'),
+  JWT_REFRESH_EXPIRES_IN: z.string().default('7d'),
+  CORS_ORIGIN: z.string().default('http://localhost:3000'),
+});
+
+const parsed = envSchema.safeParse(process.env);
+
+if (!parsed.success) {
+  console.error('❌ Invalid environment variables:', parsed.error.flatten().fieldErrors);
+  process.exit(1);
+}
+
+export const env = parsed.data;

apps/api/src/index.ts

@@ -0,0 +1,9 @@
+import { app } from './app.js';
+import { env } from './config/env.js';
+
+const PORT = parseInt(env.PORT, 10);
+
+app.listen(PORT, () => {
+  console.log(`🚀 API Server running on http://localhost:${PORT}`);
+  console.log(`📊 Environment: ${env.NODE_ENV}`);
+});

apps/api/src/middlewares/error.middleware.ts

@@ -0,0 +1,33 @@
+import type { Request, Response, NextFunction } from 'express';
+
+export class AppError extends Error {
+  constructor(
+    public statusCode: number,
+    public message: string,
+    public isOperational = true
+  ) {
+    super(message);
+    Object.setPrototypeOf(this, AppError.prototype);
+  }
+}
+
+export function errorMiddleware(
+  err: Error,
+  req: Request,
+  res: Response,
+  next: NextFunction
+) {
+  if (err instanceof AppError) {
+    return res.status(err.statusCode).json({
+      status: 'error',
+      message: err.message,
+    });
+  }
+
+  console.error('Unhandled error:', err);
+
+  return res.status(500).json({
+    status: 'error',
+    message: 'Internal server error',
+  });
+}