firebase firestore 以角度读取特定文档

Question

我想使用 AngularFire 读取 Firebase Firestore 中的特定文档。

import { Component, OnInit } from '@angular/core'; 
import { ActivatedRoute } from '@angular/router';
import { AngularFirestore , AngularFirestoreCollection, AngularFirestoreDocument } from 'angularfire2/firestore';
import { Observable } from 'rxjs';
import { async } from 'q';

@Component({
  selector: 'app-read-more-page',
  templateUrl: './read-more-page.component.html',
  styleUrls: ['./read-more-page.component.scss']
})
export class ReadMorePageComponent implements OnInit {
  postCatagory: string;
  databaseName: any; 
  uuid: string;

  documentObject:any; //real docum

  //observables 
  items: Observable<any[]>;
  doc  : AngularFirestoreDocument<any>
  post : Observable<any>;

  constructor(private route: ActivatedRoute , private afs: AngularFirestore ) {
    this.databaseName = this.route.snapshot.paramMap.get('category'); 
    this.items = afs.collection(this.databaseName).valueChanges();
  }   

  ngOnInit() {
    if(this.route.snapshot.paramMap.get('uuid') != null){ 
      //when id is not null   
      this.databaseName = this.route.snapshot.paramMap.get('category');
      this.uuid = this.route.snapshot.paramMap.get('uuid');
      console.log("UUID " , this.uuid);
      console.log("category "  ,this.databaseName);
      //read data from collection 
      //read post 
      this.doc = this.afs.doc(`${this.databaseName}/${this.uuid}`); 
    }
  }
}

${this.databaseName}/${this.uuid}是我想阅读的文件。但是作为 firestore 文档中的示例，我们可以轻松读取集合中的所有文档。但我只需要检索确切的文档。

我还是个初学者，所以如果你能提供一些适合初学者的内容，我将不胜感激

Answer 1

const docRef = afs.collection('collectionName').doc('documentId');

它会给你文档参考，然后你可以订阅snapshotChanges()或调用data()或其他方法