samle.md

//Sample I use
socket.on('disconnect', function() {
	if(typeof(socket._room) != 'undefined'){
		for(key in socket._room){
			if(Object.keys(io.sockets.adapter.rooms[socket._room[key]]).length == 0){
				delete io.sockets.adapter.rooms[socket._room[key]];
			}
		}
	}
	delete io.sockets.adapter.rooms[socket.id];
});

//Another just-quick-fix sample
socket.on('disconnect', function() {
   delete io.sockets.adapter.rooms[socket.id];
});