How can I fix the 'email is not defined' error in my Google Apps Script for adding Calendar guests?

Below is one common issue when trying to get an event by ID: the ID you see in the calendar URL isn’t always the same as the one that the Apps Script Calendar API expects. Here are some things to check and adjust:

1. Event ID Format
   The event ID in your URL (the tmeid parameter) is sometimes encoded differently than the event ID stored by CalendarApp. If you manually copy an event’s URL, the ID may contain extra characters or be in an encoded form. One way to confirm the correct event ID is to open the event in Calendar and log its ID using getId(). Compare that returned value with the one you’re using in your script. You might have to adjust your eventId string accordingly.

2. Redundant addGuest Calls
   Your code calls event.addGuest(email) immediately after fetching the event and then again inside the if block. This can be redundant and confusing. It’s best to check that event exists first and then call addGuest only once.

3. Null Event Check
   If the event isn’t found (for example, if the eventId is not exactly as expected) then event will be null and calling addGuest will cause an error. Make sure to first test for a null event before attempting to add a guest.

Here’s an updated version of your script addressing these points:

JAVASCRIPTCopied
/**
 * Sends a calendar invite to the email address provided in the form response.
 *
 * @param {Object} e The form submit event object.
 */
function onFormSubmit(e) {
  // Get the form response.
  var itemResponses = e.response.getItemResponses();

  // Get the email address from the form response.
  // Assumes the *first* text field is the email field.
  var email = "";
  for (var i = 0; i < itemResponses.length; i++){
    if (itemResponses[i].getItem().getType() === FormApp.ItemType.TEXT){
      email = itemResponses[i].getResponse();
      Logger.log(email);
      break; // Stop after finding the first text field.
    }
  }

  if (!email) {
    Logger.log("No email address found in the form response.");
    return; // Exit if no email is found.
  }

  // Get the calendar event.
  var calendarId = "lb@emailindustries.com"; // Your calendar ID
  var calendar = CalendarApp.getCalendarById(calendarId);
  Logger.log(calendar);
  
  // IMPORTANT: Make sure the eventId here exactly matches the one returned by CalendarEvent.getId().
  // The tmeid in the URL may be encoded differently.
  var eventId = "NmRsbDFvbGxmbHZnY2xhcHE3MWE5MWJ1bDEgbGJAZW1haWxpbmR1c3RyaWVzLmNvbQ";
  
  try {
    var event = calendar.getEventById(eventId);
    
    if (event) {
      event.addGuest(email);
      Logger.log("Invited " + email + " to event " + event.getTitle());
      return `Successfully invited ${email} to ${event.getTitle()}.`;
    } else {
      Logger.log(`Event with ID ${eventId} not found.`);
      return `Error: Event not found.`;
    }
  } catch (error) {
    Logger.log(`Error inviting ${email}: ${error}`);
    return `Error inviting ${email}: ${error.message}`;
  }
}

Summary

• Verify the Event ID:
  The error you’re seeing is most likely because the event isn’t found (i.e. getEventById returns null). Confirm that the event ID passed in is the same as the one the Calendar API expects. You might log the correct ID by checking an event you’ve manually added.

• Avoid Duplicate addGuest Calls:
  Only call event.addGuest(email) after you’ve confirmed the event exists.

Adjust these points and the script should work as expected.