The async pipe subscribes to an Observable or Promise and returns the latest value it has emitted. When a new value is emitted, the async pipe marks the component to be checked for changes. When the component gets destroyed, the async pipe unsubscribes automatically to avoid potential memory leaks.
@Component({
selector: 'async-observable-pipe',
template: '<div><code>observable|async</code>: Time: {{ time | async }}</div>'
})
export class AsyncObservablePipeComponent {
time = new Observable<string>((observer: Subscriber<string>) => {
setInterval(() => observer.next(new Date().toString()), 1000);
});
}