Firestore：检索单个文档

Question

我想从 Firestore 检索单个文档。所以我的意思不是集合中的文档列表（我知道怎么做）。假设我知道文档的键值对之一，我想查找文档并将其检索到 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> 

Answer 1

这是我想出的解决方案：

//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');
    });