ParentCategoryBreadcrumbs.php

<?php

namespace App\Tags;

use Statamic\Tags\Tags;

class ParentCategoryBreadcrumbs extends Tags
{
    /**
     * The {{ parent_category_breadcrumbs }} tag.
     *
     * {{ parent_category_breadcrumbs }}
     *   <li>
     *       {{ if is_current }}
     *           {{ crumb:title }}
     *       {{ else }}
     *           <a href="{{ crumb:url }}">{{ crumb:title }}</a>
     *       {{ /if }}
     *   </li>
     * {{ /parent_category_breadcrumbs }}
     *
     * @return string|array
     */
    public function categories()
    {
        $current = [
            'is_current' => true,
            'crumb' => $this->context->get('page'),
        ];
        $parents = [];
        $parent = $this->context->get('parent_category')?->value();

        while ($parent) {
            $parents[] = [
                'is_current' => false,
                'crumb' => $parent,
            ];

            $parent = $parent->parent_category;
        }

        $breadcrumbs = \array_reverse([$current, ...$parents]);

        return $this->parseLoop($breadcrumbs);
    }
}