/**
  * recurse method
  *
  * @param array  $items
  * @param string $parentId
  */
 protected function recurse($items = [], $parentId = 'root')
 {
     foreach ($items as $item) {
         $link = '#';
         $type = null;
         if (array_key_exists('document', $item)) {
             $type = 'document';
             // remove .md extension if present
             $path = ends_with($item['document'], ['.md']) ? Str::remove($item['document'], '.md') : $item['document'];
             $link = $this->codex->url($this->ref->getProject(), $this->ref->getName(), $path);
         } elseif (array_key_exists('href', $item)) {
             $type = 'href';
             $link = $item['href'];
         }
         $id = md5($item['name'] . $link);
         $node = $this->menu->add($id, $item['name'], $parentId);
         $node->setAttribute('href', $link);
         $node->setAttribute('id', $id);
         if (isset($path)) {
             $node->setMeta('path', $path);
         }
         if (isset($item['icon'])) {
             $node->setMeta('icon', $item['icon']);
         }
         if (isset($item['children'])) {
             $type = 'parent';
         }
         $node->setMeta('type', $type);
         if (isset($item['children'])) {
             $this->recurse($item['children'], $id);
         }
     }
 }