I am using Angular version 18.1.0 in a hybrid app mode environment (AngularJS + Angular 18)

I have the following code that take in input signal and compute a signal dependent on the input signal.

My component:

@Component({
  selector: 'test-component',
  standalone: true,
  imports: [NgIf],
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class TestComponent {

  form = input.required<FormGroup<TestFormModel>>();

  testsCount = computed<number>(() => this.form().controls.tests.controls.length);
  
  isLoading = computed<boolean>(() => {
    if(this.form() && this.testsCount() !== null) {
      return false;
    } else {
      return true;
    }
  });

  constructor() {}
}

Template:

<div *ngIf="!isLoading()">
   <span> Tests ({{ testsCount() }})</span>
</div>

Where the input come from (in the parent component that using the test component):

<test-component [form]="form" tabindex="0"></test-component>

I am not sure what I did wrong, but I kept getting the error from the ‘isLoading’ computed signal when the app is running:
TypeError: this.form is not a function

I not sure if the input signal is not being loaded from the parent component yet, and it is trying to compute the isLoading signal at the same time.

But I expect it to work as computed signal as it derived from input signal.