updateValueAndValidity();
updateValueAndValidity() works for control, but NOT for children ! form:FormGroup; constructor(private fb:FormBuilder) { } initForm() { this.form = this.fb.group({ ‘files’:[”, [this.fv.bind(this)]] }); } /** * my validator */ fv(fc:AbstractControl) { console.log(’validate’, fc); // … } /** * func that need to revalidate ‘files’ field */ someFunc() { // … this.form.updateValueAndValidity(); // NOT Read more about updateValueAndValidity();[…]