javascript - Angular 7 从 observable 中提取数据

Question

我是 Angular 新手。

我想从可观察对象中提取数据。我这样做:

validnomi(key : string): void {
  this.demandesnomiftodisplay = 
    this.demandenomisService.getSingleDemandenomis(key).subscribe(val => 

    {const civ = val[0].civ; 
     const datedemande = val[0].datedemande; 
     const nom = val[0].nom; 
     const prenom = val[0].prenom; 

     }
  );
}

我的服务.ts:

getSingleDemandenomis(key: string){
return this.database.list('/Demandes/DemandesBALnominatives', ref => ref.orderByKey().equalTo(key)).snapshotChanges().pipe(map(actions => {
  return actions.map(a => {
    const data = a.payload.val();
    const key = a.payload.key;
    return {key, ...data };
  });
}));
 }

但是我有这个错误:

property prenom does not exist on type {key : string}
property nom does not exist on type {key : string}
property civdoes not exist on type {key : string}

....

Answer 1

看起来是正确的，您只需要进一步读取数组的第一个元素并访问所需的属性。

您的服务:

getSingleDemandenomis(key: string): Observable<{key: string; datedemande: string}[]> {
   return this.database.list('/Demandes/DemandesBALnominatives', ref => 
       ref.orderByKey().equalTo(key)).snapshotChanges().pipe(map(actions => {
          return actions.map(a => {
              const data = a.payload.val();
              const payloadKey = a.payload.key;
              return {key: payloadKey, ...data };
          });
   }));
 }

组件:

validnomi(key : string) {
    this.demandesnomiftodisplay = this.demandenomisService.getSingleDemandenomis(key)
    .subscribe((val: {datedemande: string}[]) => console.log(val[0].datedemande));
}