HtmlRenderer::invokePageAttachmentHooks

public HtmlRenderer::invokePageAttachmentHooks(array &$page)

public function invokePageAttachmentHooks(array &$page) {
  // Modules can add attachments.
  $attachments = [];
  foreach ($this->moduleHandler->getImplementations('page_attachments') as $module) {
    $function = $module . '_page_attachments';
    $function($attachments);
  }
  if (array_diff(array_keys($attachments), ['#attached', '#cache']) !== []) {
    throw new \LogicException('Only #attached and #cache may be set in hook_page_attachments().');
  }

  // Modules and themes can alter page attachments.
  $this->moduleHandler->alter('page_attachments', $attachments);
  \Drupal::theme()->alter('page_attachments', $attachments);
  if (array_diff(array_keys($attachments), ['#attached', '#cache']) !== []) {
    throw new \LogicException('Only #attached and #cache may be set in hook_page_attachments_alter().');
  }

  // Merge the attachments onto the $page render array.
  $page = $this->renderer->mergeBubbleableMetadata($page, $attachments);
}