Caffeinated\Menus\Builder::formatGroupClass PHP Method

    public static function formatGroupClass($new, $old)
    {
        if (isset($new['class'])) {
            $classes = trim(trim(array_get($old, 'class')) . ' ' . trim(array_get($new, 'class')));
            return implode(' ', array_unique(explode(' ', $classes)));
        }
        return array_get($old, 'class');
    }

 public function active($pattern = null)
 {
     if (!is_null($pattern)) {
         $pattern = ltrim(preg_replace('/\\/\\*/', '(/.*)?', $pattern), '/');
         if (preg_match("@^{$pattern}\\z@", Request::path())) {
             $this->activate();
         }
         return $this;
     }
     $this->attributes['class'] = $this->builder->formatGroupClass(['class' => 'active'], $this->attributes);
     return $this;
 }