in packages/angular/projects/ui-angular/src/lib/components/authenticator/components/sign-up/sign-up.component.ts [21:26]
onInput(event: Event) {
let { checked, name, type, value } = <HTMLInputElement>event.target;
if (type === 'checkbox' && !checked) value = undefined;
this.authenticator.updateForm({ name, value });
}