googleSheetToCalendar.js

const calendarId = "ENTER_CALENDAR_ID";
const uniqueEventSuffix = "[MOONCAL]";
const dataRange = "A2:C";

function deleteAutoCreatedEvents() {
  var eventCal = CalendarApp.getCalendarById(calendarId);
  var startOfCurrentYear = new Date(new Date().getFullYear(), 0, 1);
  var endOfCurrentYear = new Date(new Date().getFullYear(), 11, 31)
  var events = eventCal.getEvents(startOfCurrentYear, endOfCurrentYear);
  for(var i=0; i < events.length; i++) {
    var ev = events[i];
    var title = ev.getTitle();
    if (title.indexOf(uniqueEventSuffix) >-1) {
      ev.deleteEvent();
    }
  }
}

function addEventsToCalendar() {
  var spreadsheet = SpreadsheetApp.getActiveSheet();
  var eventCal = CalendarApp.getCalendarById(calendarId);
  var rawEvents = spreadsheet.getRange(dataRange).getValues();
  var events = rawEvents.filter(function(r){
    return r.join("").length > 0;
  });

  deleteAutoCreatedEvents();
  
  for (var event of events) {
    
    var date = event[0];
    var name = event[1];
    var description = event[2];

    var lineBreak = "\r\n";
    var eventTitle = `${name} ${uniqueEventSuffix}`;
    var eventDescription = `${description} ${lineBreak}${lineBreak}via https://www.space.com/39238-full-moon-names.html`;
    
    var newEvent = eventCal.createAllDayEvent(eventTitle, date, {
      description: eventDescription,
      location: 'Up in the sky',
    });
    Logger.log(`Added ${eventTitle} on ${date} (${newEvent.getId()})`);
  }
}