The Two-Map Party Game Server: Building GameNight Without a Database

Every party game app I'd used before building this one wanted an account, a lobby website, or a subscription. I wanted the opposite: plug a laptop into the TV, run one command, and have everyone's phone connected in under thirty seconds — no internet required once the LAN is up. That constraint ends up dictating almost every architectural decision in GameNight : a Node/Express/Socket.io server that runs five real-time party games — a Mafia-style social deduction game I call Mongolpuri, UNO, a trivia quiz, Scribble, and Tic-Tac-Toe with tournament brackets — entirely from two in-memory Map s, no database, no auth, no build step on the frontend. Decision 1: A room is a plain object, not a schema const rooms = new Map (); // roomCode -> room const playerRooms = new Map (); // socketId -> roomCode const room = { code , gameType , host : socket . id , players : new Map ([[ socket . id , { id : socket . id , name , avatar }]]), status : ' lobby ' , gameState : null , timers : [], settings : defaultSettings ( gameType ), sessionStats : {}, }; Every game's state — the UNO deck, the Killer/Doctor night phase, the Scribble canvas buffer — lives in room.gameState , an untyped bag shaped differently per gameType . There's no ORM, no room class hierarchy, no GameEngine interface every game implements. Each game gets its own set of top-level functions ( startKD , kdResolveNight , startUno , unoPlayCard , …) that read and mutate room.gameState directly, dispatched through one handleAction switch: function handleAction ( room , socket , data ) { const gs = room . gameState ; if ( ! gs ) return ; switch ( room . gameType ) { case ' tictactoe ' : /* ... */ break ; case ' killerdoctor ' : kdAction ( room , socket , data ); break ; case ' scribble ' : scribbleAction ( room , socket , data ); break ; case ' uno ' : unoAction ( room , socket , data ); break ; case ' quiz ' : quizAction ( room , socket , data ); break ; } } For a five-game server built by one person, this is the right amo