The AsyncPipe subscribes to an observable or promise and returns the latest value it has emitted. When a new value is emitted, the pipe marks the component to be checked for changes.
Let's take a time observable which continuously updates the view for every 2 seconds with the current time.
@Component({
selector: 'async-observable-pipe',
template: `<div><code>observable|async</code>:
Time: {{ time | async }}</div>`
})
export class AsyncObservablePipeComponent {
time = new Observable(observer =>
setInterval(() => observer.next(new Date().toString()), 2000)
);
}
