Same name and namespace in other branches

1. 11.x core/lib/Drupal/Core/Render/theme.api.php \hook_theme_suggestions_HOOK_alter()
2. 10 core/lib/Drupal/Core/Render/theme.api.php \hook_theme_suggestions_HOOK_alter()
3. 9 core/lib/Drupal/Core/Render/theme.api.php \hook_theme_suggestions_HOOK_alter()
4. 8.9.x core/lib/Drupal/Core/Render/theme.api.php \hook_theme_suggestions_HOOK_alter()

Alters named suggestions for a specific theme hook.

This hook allows any module or theme to provide alternative template name suggestions and reorder or remove suggestions provided by hook_theme_suggestions_HOOK() or by earlier invocations of this hook.

HOOK is the least-specific version of the hook being called. For example, if '#theme' => 'node__article' is called, then node_theme_suggestions_node() will be invoked, not node_theme_suggestions_node__article(). The specific hook called (in this case 'node__article') is available in $variables['theme_hook_original'].

New suggestions must begin with the value of HOOK, followed by two underscores to be discoverable. For example, consider the below suggestions from hook_theme_suggestions_node_alter:

• node__article is valid
• node__article__custom_template is valid
• node--article is invalid
• article__custom_template is invalid

Implementations of this hook must be placed in src/Hook and tagged with the #[Hook('theme_suggestions_HOOK_alter')] attribute.

In the following example, we provide an alternative template suggestion to node templates based on the user being logged in.

function MY_MODULE_theme_suggestions_node_alter(array &$suggestions, array $variables) {
  if (\Drupal::currentUser()->isAuthenticated()) {
    $suggestions[] = 'node__logged_in';
  }
}

Parameters

array $suggestions: An array of theme suggestions, passed by reference.

array $variables: An array of variables passed to the theme hook, passed by reference. Note that this hook is invoked before any preprocessing.

See also

hook_theme_suggestions_alter()

hook_theme_suggestions_HOOK()

Related topics

File

core/lib/Drupal/Core/Render/theme.api.php, line 775

Code

function hook_theme_suggestions_HOOK_alter(array &$suggestions, array &$variables) {
  if (empty($variables['header'])) {
    $suggestions[] = 'hookname__no_header';
  }
}

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