Setting up Firestore results in: NullInjectorError: R3InjectorError(HomePageModule)

[Sulomus]

• I can without any problem set up Firebase Realtime database in a service according
  to the GitHub modular sample codes. I know it works because I
  can read, write and listen to data changes in the Firebase
  Realtimedatabase without any problem.

• But when I try to add also Firestore to the project suddenly my build
  crashes with weird error in console stating the No provider for ka!.

The full error log from console:

ERROR Error: Uncaught (in promise): NullInjectorError: R3InjectorError(HomePageModule)[FirebaseService -> FirebaseService -> ka -> ka -> ka]: 
  NullInjectorError: No provider for ka!
NullInjectorError: R3InjectorError(HomePageModule)[FirebaseService -> FirebaseService -> ka -> ka -> ka]: 
  NullInjectorError: No provider for ka!
    at NullInjector.get (core.js:11100)
    at R3Injector.get (core.js:11267)
    at R3Injector.get (core.js:11267)
    at R3Injector.get (core.js:11267)
    at injectInjectorOnly (core.js:4751)
    at ɵɵinject (core.js:4755)
    at Object.FirebaseService_Factory [as factory] (ɵfac.js? [sm]:1)
    at R3Injector.hydrate (core.js:11437)
    at R3Injector.get (core.js:11256)
    at NgModuleRef$1.get (core.js:25365)
    at resolvePromise (zone.js:1255)
    at resolvePromise (zone.js:1209)
    at zone.js:1321
    at ZoneDelegate.invokeTask (zone.js:434)
    at Object.onInvokeTask (core.js:28692)
    at ZoneDelegate.invokeTask (zone.js:433)
    at Zone.runTask (zone.js:205)
    at drainMicroTaskQueue (zone.js:620)

My app.module.ts file:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { RouteReuseStrategy } from '@angular/router';

import { IonicModule, IonicRouteStrategy } from '@ionic/angular';

import { AppComponent } from './app.component';
import { AppRoutingModule } from './app-routing.module';

import { ChartsModule } from 'ng2-charts';
import { provideFirebaseApp, initializeApp } from '@angular/fire/app';
import { getFirestore, provideFirestore } from '@angular/fire/firestore';
import { getDatabase, provideDatabase } from '@angular/fire/database';


import { environment } from 'src/environments/environment';

@NgModule({
  declarations: [
    AppComponent
  ],
  entryComponents: [],
  imports: [
    BrowserModule,
    IonicModule.forRoot(),
    AppRoutingModule,
    ChartsModule,
    provideFirebaseApp(() => initializeApp(environment.firebaseConfig)),
    provideFirestore(() => getFirestore()),
    provideDatabase(() => getDatabase()),
    ],
  providers: [
    { provide: RouteReuseStrategy, useClass: IonicRouteStrategy }
  ],
  bootstrap: [AppComponent],
})
export class AppModule {}

Relevant code for my firebase.service.ts service:

import { Injectable } from '@angular/core';
import { Database, objectVal, ref, getDatabase, set, get, onValue, onChildAdded } from '@angular/fire/database';
import { Firestore, collection, addDoc } from "firebase/firestore";

import { ChartDataSets, ChartOptions } from 'chart.js';
import { Color, Label } from 'ng2-charts';
import { Chart } from 'chart.js';

@Injectable({
  providedIn: 'root'
})
export class FirebaseService {
  constructor(
    public database: Database,
    public firestore: Firestore
    ) {
  }

  writeUserData(path, name, email) {
    set(ref(this.database, path), {
      username: name,
      email: email
    });
  }

  async writeTest(uid: string, from: string, to: string) {
    try {
      const docRef = await addDoc(collection(this.firestore, "users"), {
        first: "Ada",
        last: "Lovelace",
        born: 1815
      });
      console.log("Document written with ID: ", docRef.id);
    } catch (e) {
      console.error("Error adding document: ", e);
    }
  }
}

I also started a SO question for this issue.

[Sulomus]

If I change my imports to this, all works as it should:

import { ... } from '@angular/fire/database';
import { ... } from '@angular/fire/firestore';