class GlobalAttribute

class GlobalAttribute extends CKEditor5PluginDefault {
  
  /**
   * {@inheritdoc}
   */
  public function getDynamicPluginConfig(array $static_plugin_config, EditorInterface $editor) : array {
    // This plugin is only loaded when filter_html is enabled.
    assert($editor->getFilterFormat()
      ->filters()
      ->has('filter_html'));
    $filter_html = $editor->getFilterFormat()
      ->filters('filter_html');
    $restrictions = HTMLRestrictions::fromFilterPluginInstance($filter_html);
    // Determine which tags are allowed by filter_html, excluding the global
    // attribute `*` HTML tag, because that's what we're expanding this to right
    // now.
    $allowed_elements = $restrictions->getAllowedElements();
    unset($allowed_elements['*']);
    $allowed_tags = array_keys($allowed_elements);
    // Update the static plugin configuration: generate a `name` regular
    // expression to match any of the HTML tags supported by filter_html.
    // @see https://ckeditor.com/docs/ckeditor5/latest/features/general-html-support.html#configuration
    $dynamic_plugin_config = $static_plugin_config;
    $dynamic_plugin_config['htmlSupport']['allow'][0]['name']['regexp']['pattern'] = '/^(' . implode('|', $allowed_tags) . ')$/';
    return $dynamic_plugin_config;
  }

}