Incorrect parameter in onEventSave

I have added the following according to the documentation:


However, when i check the is_new_event property instead of a boolean an ISO date is being passed. How do I determine if the saved event is a new event or not?

It will be date of creation for new event and null for existing event. You can use it directly in if conditions, or convert to boolean if necessary

var isnew = !!is_new_event; //convert to true or false