NgForm(@ @ @ List validators, @ @ @ List asyncValidators)

Source 

NgForm(
    @Optional()
    @Self()
    @Inject(NG_VALIDATORS)
        List<dynamic> validators,
    @Optional()
    @Self()
    @Inject(NG_ASYNC_VALIDATORS)
        List<dynamic> asyncValidators) {
  this.form = new ControlGroup({}, null, composeValidators(validators),
      composeAsyncValidators(asyncValidators));
}