function TwigExtension::suggestThemeHook

Same name in other branches
  1. 10 core/lib/Drupal/Core/Template/TwigExtension.php \Drupal\Core\Template\TwigExtension::suggestThemeHook()

Adds a theme suggestion to the element.

Parameters

array|null $element: A theme element render array.

string|\Stringable $suggestion: The theme suggestion part to append to the existing theme hook(s).

Return value

array|null The element with the full theme suggestion added as the highest priority.

File

core/lib/Drupal/Core/Template/TwigExtension.php, line 669

Class

TwigExtension
A class providing Drupal Twig extensions.

Namespace

Drupal\Core\Template

Code

public function suggestThemeHook(?array $element, string|\Stringable $suggestion) : ?array {
    // Make sure we have a valid theme element render array.
    if (empty($element['#theme'])) {
        // Throw assertion for render arrays that contain more than just metadata
        // (e.g., don't assert on empty field content).
        assert(array_diff_key($element ?? [], [
            '#cache' => TRUE,
            '#weight' => TRUE,
            '#attached' => TRUE,
        ]) === [], 'Invalid target for the "|add_suggestion" Twig filter; element does not have a "#theme" key.');
        return $element;
    }
    // Replace dashes with underscores to support suggestions that match the
    // target template name rather than the underlying theme hook.
    $suggestion = str_replace('-', '_', $suggestion);
    // Transform the theme hook to a format that supports multiple suggestions.
    if (!is_iterable($element['#theme'])) {
        $element['#theme'] = [
            $element['#theme'],
        ];
    }
    // Add _new_ suggestions for each existing theme hook. Simply modifying the
    // existing items (appending to each theme hook instead of adding new ones)
    // would cause the original hooks to be unavailable as fallbacks.
    //
    // Start with the lowest priority theme hook.
    foreach (array_reverse($element['#theme']) as $theme_hook) {
        // Add new suggestions to the front (highest priority).
        array_unshift($element['#theme'], $theme_hook . '__' . $suggestion);
    }
    // Reset the "#printed" flag to make sure the content gets rendered with the
    // new suggestion in place.
    unset($element['#printed']);
    // Add a cache key to prevent using render cache from before the suggestion
    // was added. If there are no cache keys already set, don't add one, as that
    // would enable caching on this element where there wasn't any before.
    if (isset($element['#cache']['keys'])) {
        $element['#cache']['keys'][] = $suggestion;
    }
    return $element;
}

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