/**
  * Transforms an entity into an array of strings.
  *
  * Parses an entity's fields and for every field it builds an array of string
  * to be compared. Basically this function transforms an entity into an array
  * of strings.
  *
  * @param ContentEntityInterface $entity
  *   An entity containing fields.
  *
  * @return array
  *   Array of strings resulted by parsing the entity.
  */
 public function parseEntity(ContentEntityInterface $entity)
 {
     $result = array();
     $langcode = \Drupal::languageManager()->getCurrentLanguage(LanguageInterface::TYPE_CONTENT)->getId();
     // Load entity of current language, otherwise fields are always compared by
     // their default language.
     if ($entity->hasTranslation($langcode)) {
         $entity = $entity->getTranslation($langcode);
     }
     $entity_type_id = $entity->getEntityTypeId();
     // Load all entity base fields.
     $entity_base_fields = $this->entityManager->getBaseFieldDefinitions($entity_type_id);
     // Loop through entity fields and transform every FieldItemList object
     // into an array of strings according to field type specific settings.
     foreach ($entity as $field_items) {
         $field_type = $field_items->getFieldDefinition()->getType();
         $plugin_config = $this->pluginsConfig->get('field_types.' . $field_type);
         $plugin = NULL;
         if ($plugin_config && $plugin_config['type'] != 'hidden') {
             $plugin = $this->diffBuilderManager->createInstance($plugin_config['type'], $plugin_config['settings']);
         }
         if ($plugin) {
             // Configurable field. It is the responsibility of the class extending
             // this class to hide some configurable fields from comparison. This
             // class compares all configurable fields.
             if (!array_key_exists($field_items->getName(), $entity_base_fields)) {
                 $build = $plugin->build($field_items);
                 if (!empty($build)) {
                     $result[$field_items->getName()] = $build;
                 }
             } else {
                 // Check if this field needs to be compared.
                 $config_key = 'entity.' . $entity_type_id . '.' . $field_items->getName();
                 $enabled = $this->config->get($config_key);
                 if ($enabled) {
                     $build = $plugin->build($field_items);
                     if (!empty($build)) {
                         $result[$field_items->getName()] = $build;
                     }
                 }
             }
         }
     }
     return $result;
 }
 /**
  * Returns a plugin object or NULL if no plugin could be found.
  */
 protected function getPlugin($configuration)
 {
     $plugin = NULL;
     if ($configuration && isset($configuration['type']) && $configuration['type'] != 'hidden') {
         if (!isset($configuration['settings'])) {
             $configuration['settings'] = array();
         }
         $plugin = $this->diffBuilderManager->createInstance($configuration['type'], $configuration['settings']);
     }
     return $plugin;
 }