JWTが現在無効か判定する処理

function invalidJwt(jwt) {
  let jwtDec = parseJwt(jwt);
  let unixtime = JSON.parse(jwtDec)['exp'];
  let dateTime = new Date(unixtime * 1000);
  let jpTime = new Date(dateTime.toLocaleDateString('ja-JP') + " " + dateTime.toLocaleTimeString('ja-JP'));
  let nowTime = new Date();
  return nowTime.getTime() > jpTime;
}

function parseJwt(token) {
  let base64Url = token.split('.')[1];
  let base64 = base64Url.replace('-', '+').replace('_', '/');
  // デコード
  let dec = Utilities.base64Decode(base64);
  return Utilities.newBlob(dec).getDataAsString();
}