A simple example of setting-up dynamic "rooms" for socket.io clients to join

client.js

// set-up a connection between the client and the server
var socket = io.connect();

// let's assume that the client page, once rendered, knows what room it wants to join
var room = "abc123";

socket.on('connect', function() {
   // Connected, let's sign-up for to receive messages for this room
   socket.emit('room', room);
});

socket.on('message', function(data) {
   console.log('Incoming message:', data);
});

server.js

// attach Socket.io to our HTTP server
io = socketio.listen(server);

// handle incoming connections from clients
io.sockets.on('connection', function(socket) {
    // once a client has connected, we expect to get a ping from them saying what room they want to join
    socket.on('room', function(room) {
        socket.join(room);
    });
});

// now, it's easy to send a message to just the clients in a given room
room = "abc123";
io.sockets.in(room).emit('message', 'what is going on, party people?');

// this message will NOT go to the client defined above
io.sockets.in('foobar').emit('message', 'anyone in this room yet?');

How can i join room at backend with io instance and not socket instance?

How can i join room at backend with io instance and not socket instance?

Hi, I think you can, if you put your room you want to join in in the query (room:"abc123") then your server will read it upon connection
as socket.handshake.query.room;
then join the appropriate room.

Thanks!!

In the client, how to receive only the messages of the room that was created? Because in the way you gave as an example, the client receives any message and not just from the created room.

Thanks
The client will get the roomId from the server so the client will output the message to room with the roomId

Nice Tutorial, video is too good .