sockets.js

// == Client 1 ==
var socket = require('socket.io-client')('http://localhost');

const gameInfo = null
socket.emit('createGame', (createdGame) => {
	gameInfo = createdGame
})

socket.on('clientConnected', (clientId) => {
	
})


// == Client 1 ==
var socket = require('socket.io-client')('http://localhost');

const gameInfo = null
socket.emit('gameCreated', (game) => {

	// connect first created game
	socket.emit('joinGame', (game.id) => {
		gameInfo = game
	})
})



// == Server side == 

// server - some server instance

const _ = require('lodash');
const SocketIo = require('socket.io');
const io = SocketIo(server);
const uuidv1 = require('uuid/v1');

const games = {}

io.on('connection', (client) => {
	console.log('SocketIO::connect', client.id);

	client.on('createGame', (cb) => {
		// check if client.id is not in any game right now
		const isClientInGame = _(games)
			.map('clients')
			.flatten()
			.find(id => id === client.id)

		if(isClientInGame)
			return cb({
				error: 'Already in game, cant create a new one'
			})


		const id = uuidv1()
		games[id] = {
			id,
			roomName: `game-${id}`,
			clients: [client.id]
		}

		client.join(roomName)
		cb(games[uuidv1()])
		io.emit('gameCreated', games[id])
	})

	client.on('joinGame', (id, cb) => {
		// check if game exists
		if(!games[id])
			return cb({
				error: 'Game not found'
			})

		// check if client.id is not in any game right now
		const isClientInGame = _(games)
			.map('clients')
			.flatten()
			.find(id => id === client.id)

		if(isClientInGame)
			return cb({
				error: 'Already in game, cant create a new one'
			})

		// return game and join the room
		games[id].clients.push(client.id)
		client.join(games[id].roomName)
		io.to(games[id].roomName).emit('clientConnected', client.id)
		cb(games[id])
	})

	client.on('disconnect', () => {
		console.log('SocketIO::disconnect', client.id);
	});
});