Angular 9 decorators on abstract base class

You have to add an empty @Directive() decorator. As far as I know, that should be enough:

@Directive()
export abstract class BaseComponent<T extends AbstractSuperEntity> extends Toggler implements OnChanges {
  @Input()
  year: number | string

  constructor(service: MyService) {

  }

  ngOnChanges() {
  }
}