ajinkya-mhetre-mern/backend/app.js

A MERN starter with frontend and backend folders

// ===== server.js =====
const express = require('express');
const http = require('http');
const socketIo = require('socket.io');
const dotenv = require('dotenv');
const connectDB = require('./src/config/database');
const app = require('./src/app');

dotenv.config();

// Connect to database
connectDB();

const server = http.createServer(app);
const io = socketIo(server, {
  cors: {
    origin: process.env.CLIENT_URL,
    methods: ["GET", "POST"]
  }
});

// Socket.IO for real-time order tracking
io.on('connection', (socket) => {
  console.log('User connected:', socket.id);
  
  socket.on('join-room', (userId) => {
    socket.join(userId);
  });
  
  socket.on('disconnect', () => {
    console.log('User disconnected:', socket.id);
  });
});

// Make io accessible to routes
app.set('socketio', io);

const PORT = process.env.PORT;
server.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});