[英]Firestore : Retrieve a single document
I want to retrieve a single document from Firestore. 我想从Firestore检索单个文档。 So I do not mean the list of documents in the collection (I know how to do that).
所以我不是指集合中的文档列表(我知道该怎么做)。 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.
假设我知道文档的一个键值对,我想找到并将文档检索到Angular 4中。
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>
Use flatmap to return the single document data: 使用flatmap返回单个文档数据:
First import the .flatMap() property. 首先导入.flatMap()属性。
import { AngularFirestore } from 'angularfire2/firestore';
import 'rxjs/add/operator/mergeMap';
Then query your collection and limit it to 1 document: 然后查询您的集合并将其限制为1个文档:
this.afs.collection('collection', ref => ref.where('value', '==', true)
.limit(1)).valueChanges().flatMap(result => result);
Then you can subscribe to that and it will return the flatened json instead of an array. 然后你可以订阅它,它将返回flatened json而不是数组。
EDIT: 编辑:
And you can just do like this to use it in your html directly: 你可以这样做直接在你的html中使用它:
this.userInfo = this.afs.collection('collection', ref => ref.where('value',
'==', true).limit(1)).valueChanges().flatMap(result => result);
In the html code: 在html代码中:
<p>{{ (userInfo | async)?.duration }}</p>
This is the solution I came up with : 这是我提出的解决方案:
//HTML
{{userInfo}}
//TypeScript
this.afs.collection('Occupations',
ref => ref.where('id_user', '==', this.idAuth)
.limit(1))
.valueChanges()
.flatMap(result => result)
.subscribe(
v => {
let y = JSON.parse(JSON.stringify(v));
this.userInfo = y.duration;
},
(error) => {
console.log(error);
}, () => {
console.log('Finished');
});
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