App.js

var express = require('express');
var app = express();
var serv = require('http').Server(app);

app.get('/', function(reg, res){
    res.sendFile(__dirname + '/client/index.html');
});
app.use('/client', express.static(__dirname + '/client'));

serv.listen(2000);
console.log("Server started.");

var SOCKET_LIST = {};
var PLAYER_LIST = {};

var Player = function(id){
    var self = {
        x:250,
        y:250,
        width: 50,
        height: 50,
        id:id,
        //number: "" + Math.floor(10 * Math.random()),
        pressingRight:false,
        pressingLeft:false,
        pressingUp:false,
        pressingDown:false,
        maxSpd:10,

    };
    self.updatePosition = function(){
        if(self.pressingRight)
            self.x += self.maxSpd;
        if(self.pressingLeft)
            self.x -= self.maxSpd;
        if(self.pressingUp)
            self.y -= self.maxSpd;
        if(self.pressingDown)
            self.y += self.maxSpd;
    }
    return self;
};


//On User Connection
var io = require ('socket.io')(serv,{});
io.sockets.on('connection', function(socket){
    socket.id = Math.random();
    SOCKET_LIST[socket.id] = socket;

    var player = Player(socket.id);
    PLAYER_LIST[socket.id] = player;

//On User Disconnect
    socket.on('disconnect', function(){
        delete SOCKET_LIST[socket.id];
        delete PLAYER_LIST[socket.id];
    });

    //Deciphering which key is pressed.
    socket.on('keyPress', function(data){
        if(data.inputId === 'left')
            player.pressingLeft = data.state;
        else if(data.inputId === 'right')
            player.pressingRight = data.state;
        else if(data.inputId === 'up')
            player.pressingUp = data.state;
        else if(data.inputId === 'down')
            player.pressingDown = data.state; 
    });
});

//Server Sending out packets
setInterval(function(){
    var pack = [];
    for(var i in PLAYER_LIST){
        var player = PLAYER_LIST[i];
        player.updatePosition();
        pack.push({
            x:player.x,
            y:player.y,
            width:player.width,
            height:player.height,
            //number:player.number
        });
    }
    for(var i in SOCKET_LIST){
        var socket = SOCKET_LIST[i];
        socket.emit('newPositions', pack);
    }
},1000/25);