Google Apps Script Daily Birthday Notifications

DailyBirthdayReminders.js

function run() {
  const names = [];
  const today = new Date();
  const calendars = CalendarApp.getAllCalendars();
  const pat = /^(.*)\'s birthday$/;
  const subject = `Birthday Notifications for ${today.toString()}`;
  const body = "The following birthdays occur today:";
  const myEmail = Session.getActiveUser().getEmail();
  
  calendars.forEach( calendar => {
    const events = calendar.getEventsForDay(today);
    
    events.forEach( event => {
      const title = event.getTitle();
      const result = pat.exec(title);
 
      if(result) names.push(result[1]);
    });
  });

  if(names.length) {
    GmailApp.sendEmail(myEmail, subject, `${body}\n${names.join("\n")}`,
      { htmlBody: `${body}<br />${names.join("<br />")}` }
    );
  }
}