Firestore:检索单个文档 [英] Firestore : Retrieve a single document
问题描述
我想从Firestore检索单个文档.因此,我并不是说集合中的文档列表(我知道该怎么做).假设我知道文档的键值对之一,并且想在Angular 4中查找和检索该文档.
I want to retrieve a single document from Firestore. So I do not mean the list of documents in the collection (I know how to do that). Let's say I know one of the key-value pair of the document and I would like to find and retrieve the document into Angular 4.
interface Occupations {
duration: number;
id_entity: number;
id_job: number;
id_user: number;
salary: number;
start_time: number;
}
occupationDoc:AngularFirestoreDocument<Occupations>;
occupation: Observable<Occupations>;
<h1>A specific post:</h1>
<h3>{{ (occupation | async)?.salary }}</h3>
<p>{{ (occupation | async)?.id_user }}</p>
<p>{{ (occupation | async)?.duration }}</p>
<p>{{ (user | async)?.lastName }}</p>
推荐答案
使用平面图返回单个文档数据:
Use flatmap to return the single document data:
首先导入.flatMap()属性.
First import the .flatMap() property.
import { AngularFirestore } from 'angularfire2/firestore';
import 'rxjs/add/operator/mergeMap';
然后查询您的收藏并将其限制为1个文档:
Then query your collection and limit it to 1 document:
this.afs.collection('collection', ref => ref.where('value', '==', true)
.limit(1)).valueChanges().flatMap(result => result);
然后您可以订阅它,它将返回平化的json而不是数组.
Then you can subscribe to that and it will return the flatened json instead of an array.
您可以这样做,直接在html中使用它:
And you can just do like this to use it in your html directly:
this.userInfo = this.afs.collection('collection', ref => ref.where('value',
'==', true).limit(1)).valueChanges().flatMap(result => result);
在html代码中:
<p>{{ (userInfo | async)?.duration }}</p>
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