private function processToolbar(array $toolbar)
    {
        $str = '';
        foreach ($toolbar as $key => $tb) {
            $str .= sprintf("[ '%s', ", $key);
            $str .= json_encode($tb);
            $str .= '], ';
        }

        return $str;
    }
private function processToolbar(array $toolbar)
    {
        $str = '';
        foreach ($toolbar as $key => $tb) {
            $str .= sprintf("[ '%s', ", $key);
            $str .= json_encode($tb);
            $str .= '], ';
        }

        return $str;
    }
Return [ $key, [data, data] ],.

@param array $toolbar

@return string