[2023]LIFF大规模继承 因此，前面的重复使用

jQuery(function ($) {
    // URLSearchParamsオブジェクトを取得
    // http://var.blog.jp/archives/72768336.html
    var params = url.searchParams;
    if (params.get('liffId')) {
        liffId = params.get('liffId');
    }
    $(document).ready(function () {
        let myLiffId = liffId;
        initializeLiffOrDie(myLiffId);
    });
    function initializeLiff(myLiffId) {
        liff
            .init({
                liffId: myLiffId,
                //外部ブラウザでのLIFFアプリ初期化時にliff.login()メソッドを自動で実行する
                withLoginOnExternalBrowser: true, 
            })
            .then(() => {
                initializeApp();
            })
            .catch((err) => {
                console.error(err);
                document.getElementById("liffAppContent").classList.add("hidden");
                document
                    .getElementById("liffInitErrorMessage")
                    .classList.remove("hidden");
            });
    }
    function initializeApp() {
        if (!liff.isLoggedIn()) {
            liff.login({ redirectUri: location.href });
        } else {
            document.getElementById("liffAppContent").classList.remove("hidden");
        }
        idToken = liff.getAccessToken();
        getUserData(idToken);
    }
}

protected function get_line_userid()
{
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: Bearer {$this->json_obj['id_token']}"));
	curl_setopt($ch, CURLOPT_URL, 'https://api.line.me/v2/profile');
	curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	$line_profile = curl_exec($ch);
	curl_close($ch);
	// Line情報を取得
	$line_profile = json_decode($line_profile, true);
	if (!$line_profile || !isset($line_profile['userId'])) {
		return false;
	}
	return $line_profile['userId'];
}