geofence-setup.js

onDeviceReady: function () {
  var params = {
    callback: 'onGeofenceEvent',
    notifyMessage: '%2$s your home!'
  };

  //register the application to get geofencing events in the onGeofenceEvent function
  geofencing.register(params);
}

...

//status will have a indicate if the region was entered or left
function onGeofenceEvent(event) {
    console.log('region event id: ' + event.fid + ' got event with status: ' + event.status);
}