How to connect room in socket.io

Question

I'm fallowing socket.io documentation for create a chat with Room system, but when I execute fallowing code in client side, it returning "undefined"

io.to('some room').emit('some event'); // this will returning "undefined"

Because io not has function to()

Where is problem?

Answer 1

It sounds like you never joined the room. The documentation gives this code right before the code you have in your question:

io.on('connection', function(socket) {
  socket.join('some room');
});

Another this is that code shouldn't return any value (as far as I'm aware of), so with no return value it would return undefined .

Edit: to switch, you use this syntax:

socket.leave('some room');
socket.join('another room');