function hook_preprocess_HOOK in Drupal 9

Same name and namespace in other branches

1. 8 core/lib/Drupal/Core/Render/theme.api.php \hook_preprocess_HOOK()
2. 7 modules/system/theme.api.php \hook_preprocess_HOOK()
3. 10 core/lib/Drupal/Core/Render/theme.api.php \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

309 functions implement hook_preprocess_HOOK()

Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

aggregator_preprocess_block in core/modules/aggregator/aggregator.module

Implements hook_preprocess_HOOK() for block templates.

bartik_preprocess_block in core/themes/bartik/bartik.theme

Implements hook_preprocess_HOOK() for block.html.twig.

bartik_preprocess_html in core/themes/bartik/bartik.theme

Implements hook_preprocess_HOOK() for HTML document templates.

bartik_preprocess_image_widget in core/themes/bartik/bartik.theme

Implements hook_preprocess_image_widget().

bartik_preprocess_links in core/themes/bartik/bartik.theme

Implements template_preprocess_links().

... See full list

File

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

Hooks and documentation related to the theme and render system.

Code

function hook_preprocess_HOOK(&$variables) {

  // This example is from rdf_preprocess_image(). It adds an RDF attribute
  // to the image hook's variables.
  $variables['attributes']['typeof'] = [
    'foaf:Image',
  ];
}