This is a sample script for retrieving the event ID from the event URL of Google Calendar using Google Apps Script.
The event URL is like https://www.google.com/calendar/event?###
. At the event URL, ###
of https://www.google.com/calendar/event?###
is not the event ID. So it is required to convert it.
Sample script
var eventUrl = "https://www.google.com/calendar/event?###";
var eventId = Utilities.newBlob(Utilities.base64Decode(eventUrl.split("=")[1]))
.getDataAsString()
.split(" ")[0];
Logger.log(eventId);