Count unique user names in Jabbr

gistfile1.js

(function($) {
  if (typeof Array.prototype.unique !== 'function'){
    Array.prototype.unique = function() {
      var a = this.concat();

      for (var i = 0, l = a.length; i < l; ++i) {
        for (var j = i + 1; j < l; ++j) {
          if (a[i] === a[j]) {
            a.splice(j, 1);
          }
        }
      }

      return a;
    };
  }

  var chat = $.connection.chat;

  function WhenAll(requests) {
    return $.when.apply($, requests);
  }

  function ToUserNames(user) {
    return user.Name;
  }

  function OnRoomsReceived(rooms) {
    var outstandingRequests = [];

    for (var i = 0, l = rooms.length; i < l; i++) {
      var room = rooms[i];
      if (room.Count > 0) {
        var req = chat.getRoomInfo(room.Name);
        outstandingRequests.push(req);
      }
    }

    WhenAll(outstandingRequests)
      .done(function() {
        var roomDetails = arguments,
          allUserNames = [];

         for (var i = 0, l = roomDetails.length; i < l; i++) {
           var users = roomDetails[i].Users,
               names = users.map(ToUserNames);

           allUserNames = allUserNames.concat(names).unique();
         }

         console.log('Total unique users: ' + allUserNames.length);
         console.log(allUserNames);
      })
      .fail(function(reqs){
         console.log('failed');
      });
  }

  chat.getRooms().done(OnRoomsReceived);

})(jQuery);