exampleserver.js

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var port = process.env.PORT || 3000;

app.get('/', function(request, response) {
  response.sendFile(__dirname + '/views/index.html');
});

io.on('connection', function(socket){
  console.log("hi");
  socket.on('chat message', function(msg){
    io.emit('chat message', msg);
  });
});

var listener = http.listen(process.env.PORT, function() {
  console.log('Your app is listening on port ' + listener.address().port);
});