I have looked everywhere but i can’t find a tutorial or somewhere someone explains how to use this. Is there a way i can use onesignal for this?
Read the AngularFire2 docs.
You can use OneSignal, here is a doc.
Yes but this does not state how can push notification when new data is added to firebase
You can write a simple webserver who listens to changes in your DB or your app/programme uses the OneSignal or firebase push API if you add a new item.
Nothing special
Firebase support this, that’s why @AaronSterling asked him to read the AngularFire2 docs.
No need for a server, database or OneSignal
How can i do this exactly i can’t find anything that explains how i can do this
Have a look at https://firebase.google.com/docs/functions/ or more specific https://firebase.google.com/docs/functions/use-cases#notify_users_when_something_interesting_happens. Is this what you are looking for?
just wondering can it be done through service worker? as Ionic already have a service worker file? anyone?