public FormStateInterface::hasValue($key)

public FormStateInterface::isProcessingInput()

public FormStateDecoratorBase::isValueEmpty($key)

public FormStateDecoratorBase::setAlwaysProcess($always_process

hook_form_FORM_ID_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) Provide a form-specific

public FormState::getRebuildInfo() Gets

protected FormBase::logger($channel) Gets

public FormState::setProgrammed($programmed = TRUE) Sets

public ConfirmFormBase::getCancelText()

public static FormElementHelper::getElementByName($name, array $form)