How to send a message to one user in a room in socket.io?

Question

Socket.io

There are several rooms, the user can be in several at the same time. How to send a message to only one of the rooms?

Answer 1

Because rooms is essentially an ID that is added to a socket, I came to the conclusion that the socket needs to add its ID + room ID. Those. essentially drive each user into one more room, but personal. And then you can process such messages. Might help someone.

Answer 2

The documentation details all options for sending events Documentation
//sending all clients this room except sender
socket.broadcast.to('roomName').emit('broadcast', 'hello friends!');
// sending to individual socketid (private message)
io.to(socketId).emit('hey', 'I just met you');