class ContentModerationStateFormatter

class ContentModerationStateFormatter extends FormatterBase {
  
  /**
   * The moderation information service.
   *
   * @var \Drupal\content_moderation\ModerationInformationInterface
   */
  protected $moderationInformation;
  
  /**
   * Create an instance of ContentModerationStateFormatter.
   */
  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings, ModerationInformationInterface $moderation_information) {
    parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $view_mode, $third_party_settings);
    $this->moderationInformation = $moderation_information;
  }
  
  /**
   * {@inheritdoc}
   */
  public function viewElements(FieldItemListInterface $items, $langcode) {
    $elements = [];
    $workflow = $this->moderationInformation
      ->getWorkflowForEntity($items->getEntity());
    foreach ($items as $delta => $item) {
      $elements[$delta] = [
        '#markup' => $workflow->getTypePlugin()
          ->getState($item->value)
          ->label(),
      ];
    }
    return $elements;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function isApplicable(FieldDefinitionInterface $field_definition) {
    return $field_definition->getName() === 'moderation_state' && $field_definition->getTargetEntityTypeId() !== 'content_moderation_state';
  }

}