Javascript Firestore get（）集合中的所有文档都返回错误

我正在尝试使用中定义的get方法迭代集合中的所有文档，但是它对我不起作用。我得到一个get不是一个函数错误，我做错了什么

export class MainComponent implements OnInit {
    selectedCharacter: number = null;
    people: Observable<any>;
    private peopleCollection: AngularFirestoreCollection<Character>;

    constructor(private db: AngularFirestore,
          private route: ActivatedRoute,
          private location: Location) {
      this.peopleCollection = db.collection('people');
      this.people = this.peopleCollection.valueChanges();

      this.route.params.subscribe(
          params => (this.selectedCharacter = +params['id'])
      );
    }

    ngOnInit() {
        this.peopleCollection.get().then(function(querySnapshot) {
            querySnapshot.forEach(function(doc) {
                console.log(doc.id, " => ", doc.data());
            });
        });
   }
}

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TL；DR:this.peopleCollection.ref.get

收集方法valueChanges返回一个可观察的：

或者，您可以使用CollectionReference获得承诺：

---

TL；DR:this.peopleCollection.ref.get

收集方法valueChanges返回一个可观察的：

或者，您可以使用CollectionReference获得承诺：

export declare class AngularFirestoreCollection<T> {
    ...
    valueChanges(events?: DocumentChangeType[]): Observable<T[]>;
    ...
}

ngOnInit() {
    this.people.subscribe(data => console.log(data));
}

ngOnInit() {
    this.peopleCollection.ref.get().then(data => console.log(data));
}