gistfile1.js

  /**
   * Server Side
   */
  var players = [];
  var count = 0;

  sails.io.on('connection', function (socket) {
    var player = {};

    socket.on('register', function (uuid) {

      if (!(player = players[uuid])) { // New player
        count++;
        console.log('> New player - Total: '+count);
        player = players[uuid] = {uuid: uuid, tabs: 0};
        // Send new counter to all connected players
        sails.io.sockets.emit('stats', count);
      }
      else {
        // Check for multiple browser tabs opened
        if (!player.disconnected) {
          player.tabs++;
          socket.emit('error', 'too many tabs');
          socket.disconnect();
        }
      }

      // Keep player connected if a refresh occur before timeout
      if (player.disconnected) {
        clearTimeout(player.timeout);
        player.disconnected = false;
      }

      socket.emit('stats', count);
      players[uuid] = player
    }); 

    socket.on('disconnect', function (type) {
      // Don't disconnect player in-game
      if (type == 'booted' && player.tabs > 0)
        return;

      player.disconnected = true;

      player.timeout = setTimeout(function() {
        if (player.disconnected) {
          delete players[player.uuid];
          count--;
          console.log('> Player disconnected - Total: '+count);
          // Send new counter to all connected players
          sails.io.sockets.emit('stats', count);
        }
      }, 2000)
    });
  });

  /*
   * Client side
   */
  socket.on('connect', function () {
    if (!(uuid = localStorage.getItem('uuid'))) {
      var randomlyGeneratedUID = Math.random().toString(36).substring(3,16) + +new Date;
      localStorage.setItem('uuid', randomlyGeneratedUID);
    }
    
    socket.emit('register', uuid);
  });