How to get local notification when new document on firestore? Ionic 4

Hi everybody, i’m trying to put a local notification when some new document (no matter the document) is added on the collection, but it’s hard because i cannot understand how to use Node.js code with Ionic 4 (for to trigger on index.js when there is a new document on the collection, but then i have to cast a local notification on app.component.ts… so i cannot understand how to do that…) Thank you very much