Question

我是一名完全有经验的初学者，我正在学习一些课程，而我对Firestore的了解不多，我正在做一个项目，通过这个项目，我应该学习Firebase，所以请假装我是白痴还是5岁的孩子，或只回答正确的代码。谢谢。

export class ClientService {
  clientsCollection: AngularFirestoreCollection<Client>;
  clientDoc: AngularFirestoreDocument<Client>;
  clients: Observable<Client[]>;
  client: Observable<Client>;

  constructor(private afs: AngularFirestore) { 
    this.clientsCollection = this.afs.collection('clients', ref => ref.orderBy('lastName', 'asc'));
  }

  getClients(): Observable<Client[]> {
    // Get clients with the id
    this.clients = this.clientsCollection.snapshotChanges().map(changes => {
      return changes.map(action => {
        const data = action.payload.doc.data() as Client;
        data.id = action.payload.doc.id;
        return data;
      });
    });

    return this.clients;
  }

Answer 1

您需要在Observable的map下使用pipe。

import { map } from 'rxjs/operators'

this.clients = this.clientsCollection.snapshotChanges().
    .pipe(
        map(changes => {
            return changes.map(action => {
                const data = action.payload.doc.data() as Client;
                data.id = action.payload.doc.id;
                return data;
            });
        })
    );

Answer 2

使用管道 rx。（地图（...）， switchMap（...））

this.shirtCollection = afs.collection<Shirt>('shirts');
    // .snapshotChanges() returns a DocumentChangeAction[], which contains
    // a lot of information about "what happened" with each change. If you want to
    // get the data and the id use the map operator.
    this.shirts = this.shirtCollection.snapshotChanges().pipe(
      map(actions => actions.map(a => {
        const data = a.payload.doc.data() as Shirt;
        const id = a.payload.doc.id;
        return { id, ...data };
      }))
    );

此处https://github.com/angular/angularfire/blob/master/docs/firestore/collections.md

类型“ Observable <DocumentChangeAction <客户端> []>”上不存在属性“地图”

2 个答案: