child menu with current class using sage roots

childmenu.php

public function childMenu() {
    global $post;
    // Set up the objects needed
    $childQuery = new \WP_Query();
    $pages = $childQuery->query(array('post_type' => 'page', 'posts_per_page' => '-1'));
    
    if ( is_page() && $post->post_parent ){
        $childpages = get_page_children( $post->post_parent, $pages);
    }
    else{
        $childpages = get_page_children( $post->ID, $pages);
    }
    return $childpages;
}

//we need this to compare with the current page
    public function currentUrl() {
        return wp_make_link_relative(get_permalink( $post->ID ));
    }

template

<nav class="secondary-nav">
    <ul>
        @foreach($child_menu as $child)
            <li @if(wp_make_link_relative(get_permalink($child->ID)) == $current_url)class="is-active" @endif>
                <a href="{!! get_permalink($child->ID) !!}">{{$child->post_title}}</a>
            </li>
        @endforeach
    </ul>
</nav>