think\console\output\question\Confirmation::getDefaultNormalizer PHP Метод

    private function getDefaultNormalizer()
    {
        $default = $this->getDefault();
        $regex = $this->trueAnswerRegex;
        return function ($answer) use($default, $regex) {
            if (is_bool($answer)) {
                return $answer;
            }
            $answerIsTrue = (bool) preg_match($regex, $answer);
            if (false === $default) {
                return $answer && $answerIsTrue;
            }
            return !$answer || $answerIsTrue;
        };
    }