CoAuthorEntityFormPlugin.php

<?php

declare(strict_types=1);

namespace Drupal\darwin_co_authors\Plugin\FormAlter;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\pluginformalter\Plugin\FormAlterBase;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Darwin co-authors node form plugin.
 *
 * @FormAlter(
 *   id = "darwin_co_authors_form_alter_node",
 *   label = @Translation("Altering Darwin co-authors node form view."),
 *   form_id = {
 *    "node_form",
 *   },
 * )
 *
 * @package Drupal\darwin_co_authors\Plugin\FormAlter
 */
class CoAuthorEntityFormPlugin extends FormAlterBase implements ContainerFactoryPluginInterface {


  /**
   * Constructs a form alter instance.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition
    );
  }

  /**
   * {@inheritdoc}
   */
  public function formAlter(array &$form, FormStateInterface &$form_state, $form_id) {
      if (isset($form['co_authors'])) {
        $form['co_authors']['#group'] = 'author';
      }
  }
}