server.js

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

var connectionCounts = 0;

app.get('/', function (req, res) {
  res.sendFile(__dirname + '/index.html');
});

app.use("/public/js", Express.static(__dirname + '/public/js'));
app.use("/public/js", Express.static(__dirname + '/node_modules/bootstrap/dist/js'))
app.use("/public/styles", Express.static(__dirname + '/public/styles'));
app.use("/public/styles", Express.static(__dirname + '/node_modules/bootstrap/dist/css'));


io.on('connection', function (socket) {
  connectionCounts++
  io.emit('counts', connectionCounts);
  socket.on('messages', function (msg) {
    io.emit('chat message', msg);
  });

  socket.on('disconnect', () => {
    connectionCounts--;
    io.sockets.emit('counts', connectionCounts);
  });
});

http.listen(port, function () {
  console.log('listening on *:' + port);
});