Block out my work calendar with my personal events

Code.gs

function hashify(hash, [key, value]) {
  hash[key] = value;
  return hash;
}

function eventId(event) {
  if (event.isRecurringEvent()) {
    return event.getId() + "-" + event.getStartTime().toISOString() + "-" + event.getEndTime();
  }
  
  return event.getId();
}

function sync() {
  const srcId = "scott@quadhome.com";
  const syncWindowInDays = 7;
  
  const today = new Date();
  const startDate = new Date();
  startDate.setDate(today.getDate() - syncWindowInDays);
  const endDate = new Date();
  endDate.setDate(today.getDate() + syncWindowInDays);
  
  const sourceCal = CalendarApp.getCalendarById(srcId);
  const destCal = CalendarApp.getDefaultCalendar();

  const sourceEvents = sourceCal.getEvents(startDate, endDate);
  const sourceEventsById = sourceEvents
    .map(function(e) { return [eventId(e), e] })
    .reduce(hashify, {});

  const TAG_ID = "block.id";
  const destEvents = destCal.getEvents(startDate, endDate);    
  const destEventsAndSourceId = destEvents
    .map(function(e) { return [e.getTag(TAG_ID), e] })
    .filter(function([id, e]) { return id != null })
  
  // Delete stale block events  
  const existingEvents = destEventsAndSourceId  
    .filter(function([id, e]) {
      if (sourceEventsById[id]) return true;
      Logger.log("Deleting stale event: %s [id=%s]", e.getTitle(), id)
      e.deleteEvent();
    })
    .reduce(hashify, {});
  
  sourceEvents
    .filter(function(e) { return !e.isAllDayEvent() })
    .map(function(e) { return [e, existingEvents[eventId(e)]] })
    .forEach(function([sourceEvent, destEvent]) {
      if (!destEvent) {
        Logger.log("Creating new event: %s [id=%s]", sourceEvent.getTitle(), eventId(sourceEvent))

        destEvent = destCal
          .createEvent("Blocked", sourceEvent.getStartTime(), sourceEvent.getEndTime())
          .setTag(TAG_ID, eventId(sourceEvent))
          .setVisibility(CalendarApp.Visibility.PRIVATE)
          .removeAllReminders();
      }
      
      if ((destEvent.getStartTime().valueOf() != sourceEvent.getStartTime().valueOf()) || (destEvent.getEndTime().valueOf() != sourceEvent.getEndTime().valueOf())) {
        Logger.log("Correcting event: %s [sourceId=%s destId=%s]", sourceEvent.getTitle(), eventId(sourceEvent), eventId(destEvent))
        destEvent.setTime(sourceEvent.getStartTime(), sourceEvent.getEndTime())
      }
    });
}