Function is not being called - Push Notification Android

Im trying to get back my register ID from the gcm server using the push Notification plugin(ngCordova):
http://ngcordova.com/docs/plugins/pushNotifications/.

here is my code:

  var androidConfig = {
    "senderID": "900683315534",
    "ecb":"notificationReceived"
  };

  document.addEventListener("deviceready", function(){
    console.log('device is ready');
    $cordovaPush.register(androidConfig).then(function(result) {
      console.log(result);
    }, function(err) {
      console.log(err);
    })

    $rootScope.$on('notificationReceived', function(event, notification) {
      console.log(notification);
      switch(notification.event) {
        case 'registered':
          if (notification.regid.length > 0 ) {
            alert('registration ID = ' + notification.regid);
          }
          break;

        case 'message':
          // this is the actual push notification. its format depends on the data model from the push server
          alert('message = ' + notification.message + ' msgCount = ' + notification.msgcnt);
          break;

        case 'error':
          alert('GCM error = ' + notification.msg);
          break;

        default:
          alert('An unknown GCM event has occurred');
          break;
      }
    });

  }, false);

I am getting this error:

processMessage failed: Message: Jjavascript:notificationReceived({"regid":"APA91bHwMJR8jps-WorB_XyyAx0mzhCopUHFXDcBIcNoEKu0RLCDSf04NV9iob5M1bobrmO21R6HM799NrCv_G_aQdDvTtItgOReC0xvQOu_Tbsyz4AqZECDEhJrK-ozP3t7hnS1H1UZnjM_nuT1_G806wen2RBUKYWRFFtKPwvfjbOHAqN2G88","event":"registered"}) 

It seems like the my function is not being called. anyone has an idea how can i fix this?