vlsuite-1.0.x-dev/modules/vlsuite_block/modules/vlsuite_block_headings_menu/vlsuite_block_headings_menu.module

<?php

/**
 * @file
 * VLSuite - Block - Headings menu main module file.
 */

use Drupal\Core\Url;
use Drupal\Core\Link;

/**
 * Implements hook_theme().
 */
function vlsuite_block_headings_menu_theme() {
  return [
    'vlsuite_block_headings_menu_nav' => [
      'variables' => [
        'anchors_tree' => [],
        'attributes' => [],
        'inner_attributes' => [],
        'link_attributes' => [],
        'title_start_icon' => '',
        'title_end_icon' => '',
        'title' => '',
        'title_attributes' => [],
      ],
    ],
  ];
}

/**
 * Helper function to convert raw anchors tree data into renderable array.
 *
 * @param array $anchors_tree
 *   Anchors tree.
 * @param array $nav_attributes
 *   Nav attributes.
 * @param array $link_attributes
 *   Link attributes.
 *
 * @return array
 *   Nav with links build from provided anchors tree ready to render.
 */
function _vlsuite_block_headings_menu_prepare_nav_tree(array $anchors_tree, array $nav_attributes, array $link_attributes) {
  $build = [];
  foreach ($anchors_tree as $anchor => $value) {
    $is_anchor_tree = is_array($value) && !is_string($anchor);
    if ($is_anchor_tree) {
      $build[] = [
        '#type' => 'html_tag',
        '#tag' => 'nav',
        '#attributes' => $nav_attributes,
        'links' => _vlsuite_block_headings_menu_prepare_nav_tree($value, $nav_attributes, $link_attributes),
      ];
    }
    else {
      $link = Link::fromTextAndUrl($value, Url::fromUri('internal:#' . $anchor))->toRenderable();
      $link['#attributes'] = $link_attributes;
      $build[] = $link;
    }
  }
  return $build;
}

/**
 * Prepare block headings menu nav.
 *
 * @param array $variables
 *   Variables.
 */
function template_preprocess_vlsuite_block_headings_menu_nav(array &$variables) {
  $variables['tree_build'] = [
    '#type' => 'html_tag',
    '#tag' => 'nav',
    '#attributes' => $variables['attributes'],
    '#access' => !empty($variables['anchors_tree']),
    'links' => _vlsuite_block_headings_menu_prepare_nav_tree($variables['anchors_tree'], $variables['inner_attributes'], $variables['link_attributes']),
  ];
}