gistfile1.js

// Shared code
var MsgType = {
  "game start":      String.fromCharCode(0),
  "update state":    String.fromCharCode(1),
  "private message": String.fromCharCode(2)
};

var MsgTypeLookup = [
  "game start",
  "update state",
  "private message"
];

var createNetEmitter = function( EventEmitter2, socket ) {
  var receive = new EventEmitter2({ wildcard: true });
  socket.on( 'message', function( encodedString ) {
    var event = MsgTypeLookup[ encodedString.charCodeAt(0) ];
    netreceive.emit( event, encodedString.substr(1) );
  });

  var send = new EventEmitter2({ wildcard: true });
  netsend.on( '*', function( event, encodedString ) {
    socket.emit( 'message', MsgType[this.event] + encodedString );
  });

  return { receive: receive, send: send };
};


// Server code
var EventEmitter2 = require('eventemitter2').EventEmitter2;

io.sockets.on( 'connection', function( socket ) {
  var net = createNetEmitter( EventEmitter2, socket );
  net.send.emit( 'game start', 'world state goes here' );
});


// Client code
// Include the EventEmitter2 library
var socket = io.connect();
socket.on( 'connect', function() {
  var net = createNetEmitter( EventEmitter2, socket );

  net.receive.on( 'game start', function( worldState ) {
    var state = decode( worldState );
  });
});