How do I resolve the parameter type error in CalendarApp.createEvent when creating events from a spreadsheet?

The error is telling you that one of the parameters is not of type Date. The CalendarApp.createEvent method expects a signature like this:

  createEvent(title, startTime: Date, endTime: Date)

In your case, one of the date parameters (most likely startTime) is being passed as a string rather than a Date object.

What’s Happening

• Even though the cells are formatted as dates in your spreadsheet, using getValues() sometimes returns them as strings if they're not properly recognized by Apps Script.
• Thus, when you pass eventos[0] or eventos[1] to createEvent, you might be passing a string.

How to Fix It

1. Confirm Date Formatting in the Spreadsheet:
   Ensure that the cells in columns A and B are truly formatted as dates.

2. Convert the Values to Date Objects:
   Even if the cells are formatted as dates, you can enforce conversion in your script to avoid any type mismatch. For example:

JAVASCRIPTCopied
function SheetsToCalendar() {
  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  var hojaCitas = spreadsheet.getSheetByName("BBDD_Citas");
  var configCalendar = spreadsheet.getSheetByName("Config");
  var calendarID = configCalendar.getRange("C2").getValue();
  var eventCal = CalendarApp.getCalendarById(calendarID);

  var fechaHora = hojaCitas.getRange("A2:B1000").getValues();
  var titulos = hojaCitas.getRange("F2:F1000").getValues();

  for (var x = 0; x < fechaHora.length; x++) { 
    var eventos = fechaHora[x];
    var nombres = titulos[x];

    // Convert to Date objects in case they are strings
    var startTime = new Date(eventos[0]);
    var endTime = new Date(eventos[1]);
    var titulo = nombres[0];

    eventCal.createEvent(titulo, startTime, endTime);
  }
}

Note: I also adjusted the order of parameters in createEvent to match the documented signature (title, start, end).

Summary

The error occurs because at least one of your date parameters is a string. Make sure your spreadsheet cells are correctly formatted as date values, and use new Date() conversion in your code to enforce the correct type.