Angular 2 Custom Form Component: Provide a markTouched method - angular2-forms

Question

I have a custom form component that implements ControlValueAccessor. This component has an internal property touched.
export class BmInputComponent implements ControlValueAccessor, Validator {
private onTouchedCallback: () => {};
private touched: boolean = false;
registerOnTouched(fn: any) {
this.onTouchedCallback = fn;
}
onBlur() {
this.touched = true;
this.onTouchedCallback();
}
}
I need to implement a method like
markTouched() {
this.touched = true;
}
That could be called by the user of the component when markAsTouched is executed in the formControl: customInputControl.markAsTouched()
I cannot find an angular-way to do this.
#Edit:
Tried to inject the NgControl:
#Component({
selector: 'bm-input',
templateUrl: './bm-input.component.html',
encapsulation: ViewEncapsulation.None,
providers: [
{
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => BmInputComponent),
multi: true
}
]
})
export class BmInputComponent implements ControlValueAccessor, Validator {
private onTouchedCallback: () => {};
private touched: boolean = false;
constructor(#Self() #Optional() public _formControl: NgControl) {
this._viewDate = new Date();
if (this._formControl) {
this._formControl.valueAccessor = this;
this._formControl.statusChanges.subscribe(this.markTouched);
}
}
registerOnTouched(fn: any) {
this.onTouchedCallback = fn;
}
onBlur() {
this.touched = true;
this.onTouchedCallback();
}
markTouched() {
if(this._formControl.touched)
this.touched = true;
}
}
But I am getting Cannot instantiate cyclic dependency! NgControl when the component is invoked with a formControl.

Answer 1

Have you tried #SkipSelf() instead of #Self()?

Answer 2

You could try this:
constructor(private injector: Injector) {
}
ngDoCheck() {
let ngControl = this.injector.get(NgControl);
if (! ngControl.control) {
return;
}
this.touched = ngControl.control.touched;
}

Answer 3

The circular dependency is caused by having both the NG_VALUE_ACCESSOR in your #Component(...) providers, and injecting NgControl in the constructor. These are mutually exclusive.
See the example in the NG material documentation here: https://material.angular.io/guide/creating-a-custom-form-field-control#ngcontrol