“Observables Loop no modelo Angular 8” Respostas de código

Observables Loop no modelo Angular 8

//.ts file
ngOnInit(): void {
   this.pageData=this.service.getdata('/about_us_page/');  
}

//.service file
                           
getdata(tableName:string){

    return this.db.list(tableName).snapshotChanges().pipe(map(changes => {

      return changes.map(c => ({ key: c.payload.key, data:c.payload.val() }) )  }));
    //return this.db.list(tableName);
  }
             
//.html file
<ul class=""  scope="row" *ngFor="let aboutus of this.pageData |async " >             
		<li>{{aboutus.key}} {{aboutus.data.details}} </li>                               
 </ul>