edlp_d8/sites/all/modules/figli/edlp_studio/edlp_studio.module

<?php

/**
 * @file
 * Contains edlp_studio.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function edlp_studio_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the edlp_studio module.
    case 'help.page.edlp_studio':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Edlp module that handle chutier and compositions entities') . '</p>';
      return $output;

    default:
  }
}

/**
* hook_entity_extra_field_info()
*
*/
function edlp_studio_entity_extra_field_info(){
  $extra = [];
  // TODO: get node content type by settings @see readme
  $extra['node']['enregistrement']['display']['add_to_chutier'] = [
    'label' => t('Add to chutier link'),
    'description' => 'Display a link to add the content to chutier',
    'weight' => 99,
    'visible' => FALSE,
  ];
  return $extra;
}


/**
 * Implements hook_ENTITY_TYPE_view().
 * @see https://www.amazeelabs.com/en/render-menu-tree-custom-code-drupal-8
 */
function edlp_studio_node_view(array &$build, \Drupal\Core\Entity\EntityInterface $entity, \Drupal\Core\Entity\Display\EntityViewDisplayInterface $display, $view_mode) {
  $display_settings = $display->getComponent('add_to_chutier');
  if (!empty($display_settings)) {
    // dpm($entity);
    // dpm($entity->id());
    $url = Url::fromRoute('edlp_studio.chutier_controller_add_content', ['id'=>$entity->id()], array(
      'attributes' => array(
        'class' => ['add-to-chutier-link', 'ajax-link'],
        'target_id' => $entity->id(),
      )
    ));
    $build['add_to_chutier'] = array(
      '#title' => t("Add this content to chutier."),
      '#type' => 'link',
      '#url' => $url,
      '#options'=>array(
        'attributes' => array(
          'data-drupal-link-system-path' => $url->getInternalPath()
        )
      )
    );
  }
}