is-5.ts

@Component({
  selector: 'app-tweets',
  template: `
     <infinite-scroll (scrolled)="onScroll()">
       <app-tweet *ngFor="let tweet of tweets$ | async" [tweet]="tweet"></app-tweet>

       <div *ngIf="isLoading$ | async">
         Fetching tweets...
       </div>
     </infinite-scroll>
  `
})
export class TweetsComponent implements OnInit {
  ...
}