string $format_id: The date format ID.
Overrides ConfirmFormBase::buildForm
public function buildForm(array $form, array &$form_state, $format_id = NULL) {
// We don't get the format ID in the returned format array.
$this->formatID = $format_id;
$this->format = $this->configFactory
->get('system.date')
->get("formats.{$format_id}");
return parent::buildForm($form, $form_state);
}