Get link (url) to an calendar event in google apps script

For given event object of type CalendarEvent and given calendarId, the simplest and working way to build an URL to view/edit corresponding event in Google Calendar App is the following:

var splitEventId = event.getId().split('@');
var eventURL = "https://www.google.com/calendar/event?eid=" + Utilities.base64Encode(splitEventId[0] + " " + calendarId);

The best thing is that no Google API invocation, authentication, ... needed!

The new version of Google Calendar has broken this. Here's how to fix it:

var mycal = 'username@m'
var splitEventId = event.getId().split('@');
var eventUrl = "https://www.google.com/calendar/event?eid=" + 
Utilities.base64Encode(splitEventId[0] + " " + mycal).toString().replace('=','');

Allright... In 2020 this is the working version of this in case somebody is still struggling with this...

var calendarID = "[email protected]";
var event = CalendarApp.getCalendarById(calendarID).createEvent(/*SOME OPTIONS HERE*/);

var splitEventId = event.getId().split('@');

// Open the "edit event" dialog in Calendar using this URL:
var event_EDIT_URL = "https://calendar.google.com/calendar/r/eventedit/" + Utilities.base64Encode(splitEventId[0] + " " + calendarID).replace("==",'');

// Open the "view this event in a Calendar" using this URL:
var event_VIEW_IN_CAL_URL = "https://www.google.com/calendar/event?eid=" + Utilities.base64Encode(splitEventId[0] + " " + calendarID).replace("==",'');


return event_EDIT_URL; // OR return event_VIEW_IN_CAL_URL;