edlp_d8/web/modules/custom/edlp_ajax/src/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatterAjax.php

<?php

namespace Drupal\edlp_ajax\Plugin\Field\FieldFormatter;

use Drupal\Component\Utility\Html;
use Drupal\Core\Field\FieldItemInterface;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\FormatterBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Field\Plugin\Field\FieldFormatter\EntityReferenceLabelFormatter;
/**
 * Plugin implementation of the 'entity_reference_label_formatter_ajax' formatter.
 *
 * @FieldFormatter(
 *   id = "entity_reference_label_formatter_ajax",
 *   label = @Translation("Label link ajax ready"),
 *   field_types = {
 *     "entity_reference"
 *   }
 * )
 */
class EntityReferenceLabelFormatterAjax extends EntityReferenceLabelFormatter {

  /**
   * {@inheritdoc}
   */
  public static function defaultSettings() {
    return [
      // Implement default settings.
    ] + parent::defaultSettings();
  }

  /**
   * {@inheritdoc}
   */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    return [
      // Implement settings form.
    ] + parent::settingsForm($form, $form_state);
  }

  /**
   * {@inheritdoc}
   */
  // public function settingsSummary() {
  //   $summary = [];
  //   // Implement settings summary.
  //
  //   return $summary;
  // }

  /**
   * {@inheritdoc}
   */
  public function viewElements(FieldItemListInterface $items, $langcode) {
    $elements = [];
    $output_as_link = $this->getSetting('link');
    $current_langcode = \Drupal::languageManager()->getCurrentLanguage()->getId();

    foreach ($this->getEntitiesToView($items, $langcode) as $delta => $entity) {

      if ($entity->hasTranslation($current_langcode)) {
        $entity = $entity->getTranslation($current_langcode);
      }

      $label = $entity->label();
      // If the link is to be displayed and the entity has a uri, display a
      // link.
      if ($output_as_link && !$entity->isNew()) {
        try {
          $uri = $entity->urlInfo();
          $options = $uri->getOptions();
          $options += array(
            'attributes' => array(
              'class' => ['ajax-link'],
              'nid'=>$entity->id(),
              'data-drupal-link-system-path' => $uri->getInternalPath()
            )
          );
          $uri->setOptions($options);
        }
        catch (UndefinedLinkTemplateException $e) {
          // This exception is thrown by \Drupal\Core\Entity\Entity::urlInfo()
          // and it means that the entity type doesn't have a link template nor
          // a valid "uri_callback", so don't bother trying to output a link for
          // the rest of the referenced entities.
          $output_as_link = FALSE;
        }
      }

      if ($output_as_link && isset($uri) && !$entity->isNew()) {
        $elements[$delta] = [
          '#type' => 'link',
          '#title' => $label,
          '#url' => $uri,
          '#options' => $uri->getOptions(),
        ];

        if (!empty($items[$delta]->_attributes)) {
          $elements[$delta]['#options'] += ['attributes' => []];
          $elements[$delta]['#options']['attributes'] += $items[$delta]->_attributes;
          // Unset field item attributes since they have been included in the
          // formatter output and shouldn't be rendered in the field template.
          unset($items[$delta]->_attributes);
        }
      }
      else {
        $elements[$delta] = ['#plain_text' => $label];
      }
      $elements[$delta]['#cache']['tags'] = $entity->getCacheTags();
    }

    return $elements;
  }

  /**
   * Generate the output appropriate for one field item.
   *
   * @param \Drupal\Core\Field\FieldItemInterface $item
   *   One field item.
   *
   * @return string
   *   The textual output generated.
   */
  protected function viewValue(FieldItemInterface $item) {
    // The text value has no text format assigned to it, so the user input
    // should equal the output, including newlines.
    return nl2br(Html::escape($item->value));
  }

}