如何将firestore数据映射到Ionic / Angular应用程序中的typescript界面？

npm install firebase @angular/fire --save

import { AngularFireModule } from '@angular/fire';
import { AngularFirestoreModule } from '@angular/fire/firestore';

@NgModule({
  declarations: [AppComponent],
  entryComponents: [],
  imports: [
    BrowserModule,
    IonicModule.forRoot(),
    AngularFireModule.initializeApp(environment.firebaseConfig),
    AngularFirestoreModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule {}

import { Injectable } from '@angular/core';
import { AngularFirestore, AngularFirestoreCollection } from '@angular/fire/firestore';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class FirestoreService {
  private itemsCollection: AngularFirestoreCollection<Item>;
  items: Observable<Item[]>;

  constructor(private firestore: AngularFirestore) {
    this.itemsCollection = this.firestore.collection<Item>('items');
    this.items = this.itemsCollection.valueChanges();
  }

  getItems(): Observable<Item[]> {
    return this.items;
  }

  addItem(item: Item): Promise<any> {
    return this.itemsCollection.add(item);
  }

  updateItem(id: string, item: Item): Promise<void> {
    return this.itemsCollection.doc(id).update(item);
  }

  deleteItem(id: string): Promise<void> {
    return this.itemsCollection.doc(id).delete();
  }
}

import { Component } from '@angular/core';
import { FirestoreService } from 'path/to/firestore.service';
import { Item } from 'path/to/item.model';

@Component({
  selector: 'app-items',
  templateUrl: './items.page.html',
  styleUrls: ['./items.page.scss'],
})
export class ItemsPage {
  items: Item[];

  constructor(private firestoreService: FirestoreService) {
    this.getItems();
  }

  getItems(): void {
    this.firestoreService.getItems().subscribe(items => {
      this.items = items;
    });
  }

  addItem(item: Item): void {
    this.firestoreService.addItem(item);
  }

  updateItem(id: string, item: Item): void {
    this.firestoreService.updateItem(id, item);
  }

  deleteItem(id: string): void {
    this.firestoreService.deleteItem(id);
  }
}