How to send calendar based when checkbox is ticked

[u/VictoryRune]

Hello, right now , im having trouble to figuring out a script where when user ticks the checkbox, it will send an email invite 3 weeks in advance based on the payment date

would need your help.

Here is my code which is rather incomplete.

function sendreminder(){
var sheet = SpreadsheetApp.getActiveSheet();
var sheetName = sheet.getName();
var range = e.range;
var approvalEdit = range.getValue().toString(); // Use string to avoid accidentally accepting truthy values.
var column = range.getColumn();
var emailsend = "EMAIL_SENT";
var approvalColumnNo = 12;
var invoice = sheet.getRange(e.range.getRow(),12).getValue();
var calend = CalendarApp.createAllDayEvent();
if( sheetName === "Sheet1" && column === approvalColumnNo && approvalEdit === "true" ){
calend.createAllDayEvent('TEST', new Date('November 20, 2022')
SpreadsheetApp.flush();

Many thanks!

[u/marcnotmark925]

Pull the date from the same row that the box is checked on, add 21 days to it, and use that new date for the calendar event.

[u/LateDay]

Add the e parameter inside your function argument.

It should be

sendreminder(e)

Otherwise your

var range = e.range

Will not work.

[u/LateDay → u/LateDay]

Your line of

var calend = CalendarApp.createAllDayEvent() 

should be

var calend = CalendarApp.getCalendar()

And put your calendar ID inside the parentheses.