Nette\Forms\Controls\UploadControl::isOk PHP Метод

    public function isOk()
    {
        return $this->value instanceof FileUpload ? $this->value->isOk() : $this->value && array_reduce($this->value, function ($carry, $fileUpload) {
            return $carry && $fileUpload->isOk();
        }, TRUE);
    }