Rewrite Links Array to include Nesting

Question

I'm attempting to modify the language switcher links in a block so that the items are properly nested per my site's menu structure.

Currently, it outputs:

<ul>
<li>English Link</li>
<li>Japanese Link</li>
<li>Spanish Link</li>
</ul>

I need:

<ul>
<li>English Link</li>
<ul>
    <li>Japanese Link</li>
    <li>Spanish Link</li>
</ul>
</ul>

The $build['content']['#links'] array contains:

array (size=4)
  'en' => 
    array (size=5)
      'url' => 
        object(Drupal\Core\Url)[14062]
        ...
    'ja' => 
        array (size=5)
          'url' => 
            object(Drupal\Core\Url)[14062]

How can I modify this array so that elements are nested in a ul under the first link?

Answer 1

In my experience, the structure you're looking for is created by the template layer. I would not recommend changing the link array directly. A good example template is core's stable theme's menu.html.twig. It uses a recursive twig macro to create nested lists.