import { Component , OnInit } from '@angular/core' ; import { AngularFirestore } from '@angular/fire/compat/firestore' ; import { Observable } from 'rxjs' ; import { trace } from '@angular/fire/compat/performance' ; @ Component ( { selector : 'app-firestore' , template : `<p>
    Firestore!
    {{ testDocValue$ | async | json }}
    {{ persistenceEnabled$ | async }}
  </p>` , styles : [ `` ] } ) export class FirestoreComponent implements OnInit { public readonly persistenceEnabled$ : Observable < boolean > ; public readonly testDocValue$ : Observable < any > ; constructor ( firestore ) { const doc = firestore . doc ( 'test/1' ) ; this . testDocValue$ = firestore . doc ( 'test/1' ) . valueChanges ( ) . pipe ( trace ( 'firestore' ) ) ; this . persistenceEnabled$ = firestore . persistenceEnabled$ ; } ngOnInit ( ) { } }