Ionic 3 PWA & Firebase Cloud Messaging (web notifications) article required

[ionitron-bot]

Original issue by @cmer4 on 2018-02-08T16:52:27Z

Ionic version: (check one with "x")
[ ] 2.x
[x ] 3.x
[ ] 4.x

I'm submitting a ... (check one with "x")
[ ] bug report
[x] feature request

Current behavior:
If we develop Ionic 3+ based Progressive Web App (PWA) it is natural that we want to ensure push notifications are also available (subject to browser comptatibility of course. The current leading solution is to leverage FCM - Firebase Cloud Messaging.
As of now there is no documentation or a guide that explains recommended generic way of adding web notifications to Ionic 3+ based PWAs.

There are articles/guide for Angular such as this one: https://angularfirebase.com/lessons/send-push-notifications-in-angular-with-firebase-cloud-messaging/ but since Ionic has its default service worker it is unclear what is recommended implementation path specifically in Ionic 3 and going forward.

Expected behavior:
Ionic developer documentation should have a simple recipe type of a guide to implement web notifications based on FCM.