Rs\Json\Patch\Operations\Test::isValidJsonString PHP Метод

    private function isValidJsonString($string)
    {
        if (is_string($string) && strlen($string)) {
            // Decode and check last error
            $result = json_decode($string);
            return json_last_error() === JSON_ERROR_NONE && $result != $string;
        }
        return false;
    }