app\helpers\categoriesHelper::level PHP Method

    public static function level($categories, $category_id)
    {
        $cont = 0;
        foreach ($categories as $value) {
            if ($value['id'] == $category_id) {
                return 1 + self::level($categories, $value['category_id']);
            }
        }
        return 0;
    }

 public static function categoriesDropDownFormat($array, &$outPut)
 {
     foreach ($array as $row) {
         /**
          * $level
          * Contains the category tree
          * @var [type]
          */
         $level = categoriesHelper::level($array, $row['category_id']);
         $s = '';
         for ($i = 0; $i < $level; $i++) {
             $s .= '&nbsp;&nbsp;&nbsp;';
         }
         $icon = 2;
         if ($level % 3 == 0) {
             $icon = 0;
         } elseif ($level % 2 == 0) {
             $icon = 1;
         }
         $indentation = ['&#9679;', '&#8226;', '&ordm;'][$icon];
         $outPut[$row['id']] = $s . $indentation . '&nbsp;' . $row['name'];
     }
 }