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

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

Related topics

File

core/lib/Drupal/Core/Render/theme.api.php, line 604

Code

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