old_contents: const express = require('express');
  const bodyParser = require('body-parser');
  const siteSession = require('./siteConfig').siteSession;
  const router = require('./router');
  const socket = require('./socket');
  const cors = require('cors');
  
  const app = express();
  
  app.use(cors());
  app.use(bodyParser.urlencoded({extended: false}));
  app.use(bodyParser.json());
  
  router(app);
  const http = require('http').Server(app);
  //const io = require('socket.io')(http);
  //socket(io);
  
  const PORT = 3500;
  
  http.listen(PORT, function () {
    console.log('Server listening on: ' + PORT);
  });
  
new_contents: const express = require('express');
  const bodyParser = require('body-parser');
  const siteSession = require('./siteConfig').siteSession;
  const router = require('./router');
  const socket = require('./socket');
  const cors = require('cors');
  
  const app = express();
  
  app.use(cors());
  app.use(bodyParser.urlencoded({extended: false}));
  app.use(bodyParser.json());
  
  router(app);
  const http = require('http').Server(app);
  const io = require('socket.io')(http);
  socket(io);
  
  const PORT = 3500;
  
  http.listen(PORT, function () {
    console.log('Server listening on: ' + PORT);
  });
  
subject: load problem related