ThemeTestThemeHooks1.php

<?php

declare (strict_types=1);
namespace Drupal\theme_test\Hook;

use Drupal\Core\Hook\Attribute\Hook;

/**
 * Hook implementations for theme_test.
 */
class ThemeTestThemeHooks1 {
  
  /**
   * Implements hook_preprocess_HOOK() for HTML document templates.
   */
  public function preprocessHtml(&$variables) : void {
    $variables['html_attributes']['theme_test_html_attribute'] = 'theme test html attribute value';
    $variables['attributes']['theme_test_body_attribute'] = 'theme test body attribute value';
    $variables['attributes']['theme_test_page_variable'] = 'Page variable is an array.';
  }
  
  /**
   * Implements hook_theme_suggestions_HOOK().
   */
  public function themeSuggestionsThemeTestPreprocessSuggestions($variables) : array {
    return [
      'theme_test_preprocess_suggestions__' . $variables['foo'],
    ];
  }
  
  /**
   * Implements hook_preprocess_HOOK().
   */
  public function preprocessThemeTestPreprocessSuggestions(&$variables) : void {
    $variables['foo'] = 'Theme hook implementor=theme_theme_test_preprocess_suggestions().';
  }
  
  /**
   * Implements hook_theme_suggestions_HOOK().
   */
  public function themeSuggestionsThemeTestSuggestionProvided(array $variables) : array {
    return [
      'theme_test_suggestion_provided__foo',
    ];
  }
  
  /**
   * Implements hook_theme_suggestions_HOOK().
   */
  public function themeSuggestionsNode(array $variables) : array {
    $xss = '<script type="text/javascript">alert(\'yo\');</script>';
    $suggestions[] = 'node__' . $xss;
    return $suggestions;
  }

}