angular - 分页 Angular Firestore (FireBase)

Question

我想在 firestore startAt 或 startAfter 中获取接下来的 4 个文档，如果有人能做到，请帮助我

  getAllNearMeUser(city, offset, userDocumentLastKey?) {
      return this.angularFirestore.collection('members', x => 
      x.orderBy('createdAt','asc')
     .startAfter(userDocumentLastKey).limit(offset + 1))
     .snapshotChanges().map(docArray => {
      return docArray.map(doc => {
        return {
          key: doc.payload.doc.id,
          ...doc.payload.doc.data()
        };
      });
    });
  }