我正在尝试从firestore子集合中检索单个文档: 数据库/用户/ UID /动物/ docID的
我能够成功解析从另一个组件解析的docID,但我正在努力检索要在html中显示的信息:
import { Component, OnInit } from '@angular/core';
import { AuthService } from '../core/auth.service';
import { AngularFireAuth} from 'angularfire2/auth';
import { AngularFirestore, AngularFirestoreCollection, AngularFirestoreDocument } from 'angularfire2/firestore';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/mergeMap';
import { Router, ActivatedRoute } from '@angular/router';
interface Animal {
name: string;
age: number;
sex: string;
breed: string;
colour: string;
}
interface animID extends Animal {
id: string;
}
@Component({
selector: 'app-detail-animal',
templateUrl: './detail-animal.component.html',
styleUrls: ['./detail-animal.component.css']
})
export class DetailAnimalComponent implements OnInit {
curUser: any; // This used to maintain the logged in user.
animalDoc: AngularFirestoreDocument<Animal>;
animalCol: AngularFirestoreCollection<Animal>;
animalInfo: any;
petID: Observable<Animal>;
constructor(
public auth: AuthService,
private afs: AngularFirestore,
private afAuth: AngularFireAuth,
private router: Router,
public route: ActivatedRoute
) {
const petID: string = route.snapshot.paramMap.get('id');
console.log('AnimId from route: ', petID)
const user: any = this.afAuth.authState
}
private curPetID: string = this.route.snapshot.paramMap.get('id');
ngOnInit() {
this.afAuth.auth.onAuthStateChanged((user) => {
if (user) {
// get the current user
this.curUser = user.uid;
console.log('Animal ID:', this.curPetID )
console.log('Current User: ', this.curUser);
// Specify the Collection
this.animalInfo = this.afs.collection(`users/${this.curUser}/animals/`,
ref => ref.where('id', "==", this.curPetID)
.limit(1))
.valueChanges()
.flatMap(result => result)
console.log('Got Docs:', this.animalInfo);
}
});
}
}
然后在我的HTML中(现在只显示它):
<strong>Name: {{ (animalInfo | async)?.name }}</strong>
<br>Breed: {{ (animalInfo | async)?.breed }}
<br>Animal System ID: {{ (animalInfo | async)?.id }}
当我运行代码时,在console.log(&#39; GotDocs:&#39;,this.animalInfo)中返回undefined。
Got Docs:
Observable {_isScalar: false, source: Observable, operator: MergeMapOperator}
operator:MergeMapOperator {project: ƒ, resultSelector: undefined, concurrent:
Infinity}
source:Observable {_isScalar: false, source: Observable, operator: MapOperator}
_isScalar:false
__proto__:
Object
我不确定在ngOnInit()中使用上述代码是否也是正确的方法。
非常感谢任何帮助。
迈克尔
答案 0 :(得分:4)
阅读单个文档有一种更简单的方法。您已拥有ID,因此您可以指向ngOnInit中的特定文档:
const docRef = this.afs.doc(`users/${this.curUser}/animals/${this.curPetID}`)
this.animalInfo = docRef.valueChanges()
理想情况下,您在HTML中打开此数据并设置模板变量。
<div *ngIf="animalInfo | async as animal">
Hello {{ animal.name }}
</div>
或者您可以在组件TypeScript中订阅它。
animalInfo.subscribe(console.log)
答案 1 :(得分:0)
animalInfo是可观察的类型。
Angular2 +支持&#39; |异步&#39;管道直接显示可观察的类型。 因此,如果您想获得真实的数据值,您应该使用如下订阅:
const collection$: Observable<Item> = collection.valueChanges()
collection$.subscribe(data => console.log(data) )
我希望这会有所帮助:)
答案 2 :(得分:0)
你想做&#34;(animalInfo | async)动物&#34;在ngIf(推荐的解决方案)
然后你的html中不再需要异步管道,请记得在括号{{}}中使用新名称。如果你忘记了你给对象的名字,只需使用{{animal | json}}这将把对象显示为json文本。
const ref = 'location in db';
const animalInfo$: Observable<Item>;
constructor(private service: Firestore) {
this.animalInfo$ = this.service.doc(ref).valueChanges();
}
或者你可以在构造函数()/ onInit()(备份解决方案)中执行异步部分
const ref = 'location in db';
const animalInfo: Item;
constructor(private service: Firestore) {
this.service.doc(ref).subscribe(item => {
this.animalInfo = item;
console.log(item);
);
}
然后你可以在你的HTML中再次这样做 {{animalInfo | json}}