<h3>AsyncPipe with NgIf</h3>

<div *ngIf="promiseBook | async as book; else loading">
   Id: {{book.id}}, Name: {{book.name}}
</div>
<ng-template #loading>Loading Data...</ng-template>

<h3>AsyncPipe with NgSwitch</h3>

<div [ngSwitch]="(promiseBook | async)?.id">
  <div *ngSwitchCase="100">Find Actual Data</div>
  <div *ngSwitchDefault>Showing Default Data</div>
</div>