thanks @endel & @seiyria ! I'll give it a try

How can I sync a part of state (i.e. player's hand or a just-drawn card) with only one player, so that others do not get the state? I want to protect against looking at socket's data in browser's dev console and modifying javascript to listen to another player's data, so simply .listen()-ing to only a part of server's state is not an option...