index.js

var express = require('express');
var app = require('express')();
var http = require('http').createServer(app);
var io = require('socket.io')(http);
var timer = require('./public/shuffle.js');

app.use(express.static('public'));

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

var port = process.env.PORT || 5000;
http.listen(port, function () {
  console.log('listening on *:5000');
});

// Socket connection as well as data transmission happens below:

var totalCoder = 0;
var currentCoders = [];
var code = '';
io.on('connection', function (socket) {
  // to properly calculate total nums:
  var addedUser = false;

  var coder = {
    name: '',
  };

  // connects and registers name
  socket.on('userName', function (in_name) {
    if (addedUser) return;

    addCoder();
    addedUser = true;

    coder.name = in_name;
    currentCoders.push(in_name);
    io.sockets.emit('update', {
      num: totalCoder,
      who: currentCoders,
      news: in_name, // updates on who joined
    });
  });

  // when client pushes code, it's stored in the global code
  socket.on('pushCode', function (data) {
    console.log(`${socket.id} pushed code.`);
    code = data;
    io.sockets.emit('consoleUpdate', { person: coder.name, action: 'push' });
  });

  // when coders pull, it't updated to that one client only
  socket.on('pullCode', function (data) {
    console.log(`${socket.id} pulled update.`);
    io.to(socket.id).emit('update_global', code);
    io.sockets.emit('consoleUpdate', { person: coder.name, action: 'pull' });
  });

  // force updates to all
  socket.on('updateAll', function (data) {
    console.log(`${socket.id} updated to all users.`);
    code = data;
    io.sockets.emit('update_global', code);
    io.sockets.emit('consoleUpdate', {
      person: coder.name,
      action: 'push_all',
    });
  });

  // reactions:
  socket.on('reaction', function (data) {
    io.sockets.emit('reactions', { person: coder.name, reaction: data });
  });

  // Timer
  socket.on('startTimedPlay', function (data) {
    console.log(timer.shuffle(currentCoders));
    var shuffle = timer.shuffle(currentCoders);
    io.sockets.emit('startGlobalTimer', shuffle);
  });

  socket.on('stopTime', function (data) {
    io.sockets.emit('stopGlobalTimer', '');
  });

  // when coder disconencts, update number:
  socket.on('disconnect', function (data) {
    // only disconnects user when it's connected already:
    if (addedUser) {
      subCoder();
      currentCoders.splice(currentCoders.indexOf(coder.name), 1);
      io.sockets.emit('update_leave', {
        num: totalCoder, // updates on total number
        who: currentCoders, // updates on who's in the room
        news: coder.name, // updates on who left
      });
    }
  });
});

// methods:
function addCoder() {
  totalCoder++;
}

function subCoder() {
  totalCoder--;
}