Creating chat "rooms" using Node, Express, Heroku, and Socket.io - ios

Question

So I've been building an app for quite some time and I'm running into problems in terms of scalability. I'm new to Node, and Heroku for that matter. Please bear with me.
I originally followed this tutorial to get my node service up and running. Essentially, it creates a real-time chat service. However, my question now comes with creating 'rooms'. It doesn't make sense to me that I might have 15+ chats going on, yet they all are calling the same functions on the same clientSocket, and I have to determine what UI updates go to which clients on the front end. As of now, I have upwards of 15 clients all trying to interact on different chats, but I'm pushing updates to everyone at once (for example, when a message is posted), then determining who's UI to update based on which room ID I'm cacheing on each device. Seems like a terrible waste of computing power to me.
I'm thinking that the solution involves modifying how each client connects (which is the code snippet below). Is there a way to create location based 'rooms', for example, where the clients connected are the only ones getting those updates? Any idea how to go about this solution? If anyone is also willing to just explain what I'm not understanding about Node, Express, Heroku, Socket.io or others, please do let me know.
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var pg = require('pg');
var userList = [];
var typingUsers = {};
var ActiveQueue = [];
app.get('/', function(req, res){
res.send('<h1>Active RT Queue</h1>');
});
var conString = "postgres://url";
pg.defaults.ssl = true;
var client = new pg.Client(conString);
client.connect(function(err) {
if(err) {
return console.error('could not connect to postgres', err);
}
});
http.listen(process.env.PORT || 5000, function(){
console.log('Listening on *:5000');
});
io.on('connection', function(clientSocket){
console.log('a user connected');
clientSocket.on('disconnect', function(){
console.log('user disconnected');
var clientNickname;
for (var i=0; i<userList.length; i++) {
if (userList[i]["id"] == clientSocket.id) {
userList[i]["isConnected"] = false;
clientNickname = userList[i]["nickname"];
break;
}
}
delete typingUsers[clientNickname];
io.emit("userList", userList);
//io.emit("userExitUpdate", clientNickname);
//io.emit("userTypingUpdate", typingUsers);
});
clientSocket.on("exitUser", function(clientNickname){
for (var i=0; i<userList.length; i++) {
if (userList[i]["id"] == clientSocket.id) {
userList.splice(i, 1);
break;
}
}
io.emit("userExitUpdate", clientNickname);
});
clientSocket.on("connectUser", function(clientNickname) {
var message = "User " + clientNickname + " was connected.";
console.log(message);
var userInfo = {};
var foundUser = false;
for (var i=0; i<userList.length; i++) {
if (userList[i]["nickname"] == clientNickname) {
userList[i]["isConnected"] = true
userList[i]["id"] = clientSocket.id;
userInfo = userList[i];
foundUser = true;
break;
}
}
if (!foundUser) {
userInfo["id"] = clientSocket.id;
userInfo["nickname"] = clientNickname;
userInfo["isConnected"] = true
userList.push(userInfo);
}
io.emit("userList", userList);
io.emit("userConnectUpdate", userInfo)
});
///functions pertaining to transfer of messages and updating the UI follow

Answer 1

I would try something like this:
io.on('connection', function(clientSocket) {
clientSocket.on('room:general', function(data) {
var user = data.user;
var message = data.message;
console.log('%s sent new message: %s',user,message);
io.emit('room:general:newMessage', data);
});
//and so for each room
.........
});
and from front end you need to send JSONObject:
{
user:your_username,
message:user_message
}
,
socket.emit("room:general", json_object);
socket.on("room:general:newMessage", onYourDefinedEmiterListener);
..........
..........
//and so for each room
I never made Chat Application, hope it helps.