Additional attribute for menu link

Question

How I can add itemprop="url" for each link (<a>) in main menu?

So, I need to get from

<a href="/node/114" data-drupal-link-system-path="node/114">Test</a>

to

<a href="/node/114" data-drupal-link-system-path="node/114" itemprop="url">Test</a>

Is it possible to do it in preprocess? I would like not to use any module for this.

Answer 1

Try

function HOOK_link_alter(&$variables) or function HOOK_preprocess_menu(&$variables)

Or just override the menu template (menu--main.html.twig) and replace line

{{ link(item.title, item.url, {'class': link_classes}) }}

with

{{ link(item.title, item.url, item.attributes.addClass(link_classes).setAttribute('itemprop', 'url') }}