Google Apps Script

function ReadSpreadSheetById(id) {
  var ss = SpreadsheetApp.openById(id);
  var sheet = ss.getSheets()[0]
  var data = sheet.getDataRange().getValues()

  return {
    name:ss.getName(),
    url:ss.getUrl(),
    sheetName:sheet.getName(),
    data
  }
}

function CheckReplyThenSend(subject,htmlBody){
  var thread = GmailApp.search(`in:anywhere subject:"${subject}" `)[0];

  if (thread){
    thread.reply("", {
      htmlBody: htmlBody,
    });
  }else{
    SendEmailToMe(subject,htmlBody)
  }

  var emailQuotaRemaining = MailApp.getRemainingDailyQuota();
  Logger.log("Remaining email quota: " + emailQuotaRemaining);
}

function SendEmailToMe(title,htmlBody){
    const myEmail = Session.getActiveUser().getEmail();
    MailApp.sendEmail({
        to: myEmail, 
        subject: title,
        htmlBody
    });
}

function GetHoliday(){
  // go your calendar and check 'Holidays in Taiwan' is subscribed and copy id from 'Holidays in Taiwan'->setting
  var calendar = CalendarApp.getCalendarById('en.taiwan#holiday@group.v.calendar.google.com');
  Logger.log(calendar);
}