I'm developing a game that has a lot of rooms and most rooms will have between 2 and 15 users. On the UI there is a list of all the players currently in the room. I'm wondering, when someone joins a room, should the server send the entire list of players (admittedly not much) to everyone, or just the delta?
Option 1) Send the entire list to the new person joining because he needs all of them and send the one user to the rest of the players because they already know who else is in the room. Possible synchronization issues and harder to code.
Option 2) When someone enters or leaves a room, resend the entire list of players to everyone. No synchronization issues, much easier to code and test, but increased packet sizes.
Which option would you choose or is there a third one? For reference I'm using node.js and socket.io.