horizontal_tabs-8.x-1.x-dev/horizontal_tabs.module

<?php

/**
 * Implements hook_theme().
 */
function horizontal_tabs_theme($existing, $type, $theme, $path) {
  return [
    'horizontal_tabs' => [
      'render element' => 'element',
    ],
  ];
}

/**
 * Prepares variables for horizontal tabs templates.
 *
 * Default template: horizontal-tabs.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties and children of
 *     the details element. Properties used: #children.
 */
function template_preprocess_horizontal_tabs(&$variables) {
  $element = $variables['element'];
  $variables['children'] = (!empty($element['#children'])) ? $element['#children'] : '';
}