How to pass variable value from html.html.twig to page-title.html.twig

Question

Adding a dump 'dd()' to parent html.html.twig template file when rendering a 'page type' page I get, among others, the following pair: "node_type" => "page" that I can render within this very template file. When rendering an 'article type' page I get "node_type" => "article". So far so good.

Now I'd need to make use of that variable (node_type) in child template page-title.html.twig. Same dump function retrieves some other variable-value pairs but not the node_type one. I guess they're 'local variables' that are not available out of their own scope. However there may be some way to pass it from parent template but I couldn't find a straightforward simple solution to it. Any clue?

I'm using latest Drupal 9 stable release, so Twig 2 is in charge of theming.

T.I.A.

Answer 1

You can't pass variables between the two templates as such, but you can make node_type available in page-title.html.twig by copying the code from node_preprocess_html, which is responsible for getting it into html.html.twig in the first place:

function MODULEorTHEME_preprocess_page_title(&$variables) {
  if (($node = \Drupal::routeMatch()->getParameter('node')) || ($node = \Drupal::routeMatch()->getParameter('node_preview'))) {
    if ($node instanceof NodeInterface) {
      $variables['node_type'] = $node->getType();
    }
  }
}