Prevent duplicate calendar events from Apps Script - google-apps-script

Question

I've read through a number of posts on SO and elsewhere as to how to prevent a script from continuing to add duplicate calendar events each time it's run. I've been unsuccessful so far in stopping the duplicates.
Here's my code:
function onOpen() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var menuEntries = [ {name: "Push to Calendar", functionName: "sendCalendarEvents"} ];
ss.addMenu("Custom Menu", menuEntries);
}
function sendCalendarEvents() {
var spreadsheet = SpreadsheetApp.getActiveSheet();
var calendarId = spreadsheet.getRange('G1').getValue();
var eventCal = CalendarApp.getCalendarById(calendarId);
var lastRow = spreadsheet.getLastRow();
var count = spreadsheet.getRange("A3:E"+lastRow+"").getValues();//five columns
var minutesBefore = 462
for (x=0; x<count.length; x++) {
var row = count[x];
var title = row[0];
var startTime = row[1];
var endTime = row[2];
var guests = row[3];
var description = row[4];
var location = row[5];
var id = row[7];no row[7]
var options = {
'location': location,
'description': description,
'guests':guests +',',
'sendInvites': 'True',
}
if(!id) {
var event = eventCal.createAllDayEvent(title, startTime, options);
var newEventId = event.getId();
spreadsheet.getRange(x+3,7).setValue('yes');
spreadsheet.getRange(x+3,8).setValue(newEventId);
event.addEmailReminder(minutesBefore);
Logger.log('Event ID: ' + event.getId());
and here's my spreadsheet (with 'test' data)
I've also tried variations of the 'if' statement (like if (row[x][7] != 'yes')...create the event) but that hasn't worked either.
Any help? After the duplicate issue is resolved, I then want to be able to have a user edit the date or title or such of an event in the spreadsheet and have the existing event deleted and then a new event (with the updated title/date) be created...if that's possible.
Thanks for any help you can provide!

Answer 1

You only have five columns in your data. There is no row[7]
var count = spreadsheet.getRange("A3:E"+lastRow+"").getValues();//only five columns in your data
var minutesBefore = 462
for (x=0; x<count.length; x++) {
var row = count[x];
var title = row[0];
var startTime = row[1];
var endTime = row[2];
var guests = row[3];
var description = row[4];
var location = row[5];
var id = row[7];//Problem is right here...there is no row[7];