Tracking and engaging users are key features necessary for your app to grow. That means you should be able to register and authenticate users. Once the users start using the app, you also need to segment the users so that you can customize their interactions. Then, you can send push notifications to encourage users to revisit the app.
There are three components that you need to use for your project, as follows:
Ionic Cloud: This is a cloud service that helps save user information and coordinate push notifications between you, Apple, or Google and the end users' devices.
Ionic Cloud Angular module: This is just an Angular module to import to your local project. It provides some simple utilities for your code to interface with Ionic Cloud. Otherwise, directly calling Ionic Cloud API would be very complex.
Cordova Push Notification and InAppBrowser: Since your code is in JavaScript, you need to communicate with the device's native features, such as push notification.