function hook_preprocess_HOOK

Preprocess theme variables for a specific theme hook.

This hook allows modules to preprocess theme variables for a specific theme hook. It should only be used if a module needs to override or add to the theme preprocessing for a theme hook it didn't define.

For more detailed information, see the Theme system overview topic.

Parameters

array $variables: The variables array (modify in place).

Related topics

File

core/lib/Drupal/Core/Render/theme.api.php, line 610

Code

function hook_preprocess_HOOK(&$variables) : void {
  // This example is from \Drupal\node\Hook\NodeThemeHooks::preprocessHtml().
  // It adds the node type to the body classes, when on an individual node page
  // or node preview page.
  if (($node = \Drupal::routeMatch()->getParameter('node')) || $node = \Drupal::routeMatch()->getParameter('node_preview')) {
    if ($node instanceof NodeInterface) {
      $variables['node_type'] = $node->getType();
    }
  }
}