NG_VALIDATORS
An InjectionToken for registering additional synchronous validators used with
AbstractControls.
const NG_VALIDATORS: InjectionToken<readonly (Function | Validator)[]>;
See also
Usage notes
Providing a custom validator
The following example registers a custom validator directive. Adding the validator to the
existing collection of validators requires the multi: true option.
@Directive({
selector: '[customValidator]',
providers: [{provide: NG_VALIDATORS, useExisting: CustomValidatorDirective, multi: true}]
})
class CustomValidatorDirective implements Validator {
validate(control: AbstractControl): ValidationErrors | null {
return { 'custom': true };
}
}