Hide empty product categories from Main Navigation in WooCommerce

You can of course add unlimited WooCommerce Product Categories into your main navigation. But sometimes they get empty because of Stock change or similar. If you automatically want to hide empty product categories in your WordPress Navigation place the code below into your functions.php file.

add_filter( 'wp_get_nav_menu_items', 'nav_remove_empty_category_menu_item', 10, 3 );
function nav_remove_empty_category_menu_item ( $items, $menu, $args ) {
    global $wpdb;
    $nopost = $wpdb->get_col( "SELECT term_taxonomy_id FROM $wpdb->term_taxonomy WHERE count = 0" );
    foreach ( $items as $key => $item ) {
        if ( ( 'taxonomy' == $item->type ) && ( in_array( $item->object_id, $nopost ) ) ) {
            unset( $items );
        }
    }
    return $items;
}