Socket.io server on Heroku

index.js

const app = require('express')();

// Heroku header fixes
app.use(function (req, res, next) {
  res.setHeader(
    'Access-Control-Allow-Origin',
    'http://' + req.headers.host + ':8100',
  );
  res.setHeader(
    'Access-Control-Allow-Methods',
    'GET, POST, OPTIONS, PUT, PATCH, DELETE',
  );
  res.setHeader(
    'Access-Control-Allow-Headers',
    'X-Requested-With,content-type',
  );
  next();
});

// Connect http to express
const http = require('http').Server(app);

// Socket.io init
const io = require('socket.io')(http, {
  cors: {
    origins: ['http://localhost:8080', 'https://your.app'], // Localhost for testing and your client url
    methods: ['GET', 'POST'],
  },
  // Default:pingInterval: 10000,
  // Default:pingTimeout: 5000,
});

// Socket events
io.on('connection', function (socket) {
  // Query params
  const queryParamValue = socket.handshake.query.queryParamKey;


  socket.on('disconnect', function () {
      console.log('Disconnect');
  });
});

const PORT = process.env.PORT || 3000;

http.listen(PORT, () => {
  console.log('listening on port ' + PORT);
});