progressive-image#toggle-image.ts

@Directive({
  selector: 'img[appProgressiveImage]',
  providers: [...]
})
export class ProgressiveImageDirective implements OnInit, Dimensions {
  // ...
  @HostBinding('style.display') display = Display.flex;
   
  constructor(private imageState: ImageStateService) {}

  ngOnInit() {
    this.imageState.isLoaded$.subscribe(loaded => {
      this.display = loaded ? Display.flex : Display.none;
    });
  }
}