import { FormGroup } from '@angular/forms'; export function ConfirmedValidator(controlName: string, matchingControlName: string){ return (formGroup: FormGroup) => { const control = formGroup.controls[controlName]; const matchingControl = formGroup.controls[matchingControlName]; if (matchingControl.errors && !matchingControl.errors['confirmedValidator']) { return; } if (control.value !== matchingControl.value) { matchingControl.setErrors({ confirmedValidator: true }); } else { matchingControl.setErrors(null); } } }