knowledge-8.x-1.x-dev/modules/knowledge_field/src/Plugin/Field/FieldFormatter/KnowledgeCompetencyRoleFormatter.php

<?php

declare(strict_types=1);

namespace Drupal\knowledge_field\Plugin\Field\FieldFormatter;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\FormatterBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin implementation of the 'Competency Role' formatter.
 *
 * @FieldFormatter(
 *   id = "knowledge_competency_role",
 *   label = @Translation("Competency Role"),
 *   field_types = {"knowledge_competency_role"},
 * )
 */
final class KnowledgeCompetencyRoleFormatter extends FormatterBase {

  /**
   * {@inheritdoc}
   */
  public static function defaultSettings(): array {
    $setting = ['foo' => 'bar'];
    return $setting + parent::defaultSettings();
  }

  /**
   * {@inheritdoc}
   */
  public function settingsForm(array $form, FormStateInterface $form_state): array {
    $elements['foo'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Foo'),
      '#default_value' => $this->getSetting('foo'),
    ];
    return $elements;
  }

  /**
   * {@inheritdoc}
   */
  public function settingsSummary(): array {
    return [
      $this->t('Foo: @foo', ['@foo' => $this->getSetting('foo')]),
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function viewElements(FieldItemListInterface $items, $langcode): array {
    $element = [];
    foreach ($items as $delta => $item) {
      $element[$delta] = [
        '#markup' => $item->value,
      ];
    }
    return $element;
  }

}