Push Notifications Ionic - node.js

Question

First of all, I'm developing a proyect in Ionic (front-end), Node.js + Express (backend) and MongoDB as DB and, I want to implement push notification in my app. I've read a lot about notification using firebase but I'm using MongoDB. I'm quite lost if anyone could help/guide me, I'd appreciate it.

Answer 1

You can use Firebase push or Firebase cloud messaging with your app without any issue. It is just one service of Firebase family. You don't need to use its real-time database with your app. You just need to integrate Firebase cloud messaging service only. i.e. you can keep Mongodb backend as it is now.
Article about Firebase Push and Ionic 4

Answer 2

If you don't want to use firebase and/or you want push notifications even if you are offline, there is this Cordova plugin you can use: cordova-plugin-local-notifications.
Quick instructions here. Not-so-quick instructions: read the documentations and issues in github.
Install like this:
ionic cordova plugin add cordova-plugin-local-notification
npm install #ionic-native/local-notifications
Then import and include the provider in app.module.ts (don't forget this step, usually not included in any manual):
import {LocalNotifications} from '#ionic-native/local-notifications/ngx';
...
providers: [ LocalNotifications ]
Then import and inject in your_page.page.ts:
import {LocalNotifications} from '#ionic-native/local-notifications/ngx';
...
constructor(private localNotifications: LocalNotifications) {}
And finally use it like this:
this.localNotifications.schedule({
title: 'My first notification',
text: 'Thats pretty easy...',
foreground: true
});
Test it thoroughly, the plugin is not bugfree, but works.
Hope this helps.