Ionic geofence

Hi all,
I am using ionic v3 and want to use Ionic built in Geofence plugin.
I have implemented as mentioned in the official docs

private addGeofence() {
//options describing geofence
let fence = {
id: ‘69ca1b88-6fbe-4e80-a4d4-ff4d3748acdb’, //any unique ID
latitude: 37.285951, //center of geofence radius
longitude: -121.936650,
radius: 100, //radius to edge of geofence in meters
transitionType: 3, //see ‘Transition Types’ below
notification: { //notification settings
id: 1, //any unique ID
title: ‘You crossed a fence’, //notification title
text: ‘You just arrived to Gliwice city center.’, //notification body
openAppOnClick: true //open app when notification is tapped

() => console.log(‘Geofence added’),
(err) => console.log(‘Geofence failed to add’)

The issue which i am getting is, i am unable to find out when it comes specifically inside or exit. In both cases, promise is returning success(which says ‘ok’). For notification purpose , i need to know specific condition based on entering and exiting.

Thanks a lot