degov-8.x-2.0/modules/degov_social_media_youtube/degov_social_media_youtube.module

<?php

/**
 * @file
 * Contains youtube_feed_block.module.
 */

use Drupal\Component\Utility\Xss;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function degov_social_media_youtube_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the degov_social_media_youtube module.
    case 'help.page.degov_social_media_youtube':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('This module allows you to show you the newest videos of one youtube channel') . '</p>';
      return $output;

    default:
  }
}

/**
 * @param $variables
 */
function degov_social_media_youtube_preprocess_block(&$variables) {
  if (isset($variables['elements']['#base_plugin_id']) && $variables['elements']['#base_plugin_id'] == 'degov_social_media_youtube') {
    $variables['#attached']['library'][] = 'degov_common/slick';
    $markup = render($variables['content']);

    if (!empty($markup)) {
      $variables['#attached']['drupalSettings']['degov_social_media_settings']['code']['yt'] = $markup;
      $variables['attributes']['class'][] = 'js-social-media-wrapper';
      $variables['attributes']['data-social-media-source'] = 'youtube';
      $variables['attributes']['data-social-media-entity'] = 'yt';
      $variables['social_media_disabled'] = TRUE;
    }
  }
}

/**
 * Implements hook_theme().
 */
function degov_social_media_youtube_theme() {
  return [
    'degov_social_media_youtube' => [
      'render element' => 'elements',
      'variables' => [
        'title' => NULL,
        'videoID' => NULL,
        'thumbnail' => NULL,
        'link_display' => NULL,
        'caption' => NULL,
        'date' => NULL,
        'views' => NULL,
        'comments' => NULL,
        'likes' => NULL,
      ],
    ],
  ];
}