FullCalendar - selectOverlap prevents creation of allday events - fullcalendar

Question

Because selectOverlap function only passes through the event being overlapped, and not the selection, it is difficult to customise how to handle event creation.
In my case, we are working on a calendar/diary system, with background events showing the employee's shifts, and events showing their individual bookings.
At this point, other than the background events - absolutely no events should be able to overlap each other.
However... on top of that - we are then overlaying 'all day events' - which might be any number of things, but for examples sake, let's say they're 'staff birthdays' - therefore, you might have a couple of events today, but there will be an event in the all day section, showing someone's birthday.
I am checking for eventOverlap and doing some other checks on eventDrop and eventResize which handle different clashes, but these only work for existing events being moved or resized. I would like to do the same on event creation - which happens during the select. In order to disallow the select of spaces which already have events, I am using the example function from the selectOverlap documentation:
function(event) {
return event.rendering === 'background';
}
This works fantastically. However, if I try to create a new All Day event, it will 'overlap' any other events that exist on that day, and not pass this check.
I was hoping to be able to use the selection's object to check it for an allDay=true, but the function is only passed the existing event, and there is no way to check the selected section.
You can see a very simplified demo here:
https://codepen.io/anon/pen/NQrxOO
Try to create an allday event on the day which already has events.
Is there a better way to do this? I can completely remove the selectOverlap and do everything in the select callback instead, but I would need to essentially duplicate the overlap checks just to make this work, and I feel like that seems like overkill for something that should be relatively simple.
Is it possible to get not only the overlapped event object, but also the selection object when doing a selectOverlap function?

Answer 1

Current workaround is to remove the selectOverlap check, and instead do it myself within the select callback.
Below is a simplified version of a quick function I wrote to call when using select={this.handleEventCreate}:
class Diary extends React.Component {
//additional functions, state definitions, etc etc etc here.
//Define calendarRef as it will be needed in the function below
calendarRef = React.createRef();
handleEventCreate = (info) => {
// Get the Calendar API to allow unselection
let calendarApi = this.calendarRef.current.getApi();
// Get all Events
let checkEvents = calendarApi.getEvents();
// Loop through them
checkEvents.forEach(function(event){
// If it's not a background element, check whether the new element contains the existing, or vice versa.
if(event.rendering !== "inverse-background" &&
(
(event.start >= info.start && event.start <= info.end) ||
(event.end >= info.start && event.end <= info.end) ||
(info.start >= event.start && info.start <= event.end) ||
(info.end >= event.start && info.end <= event.end)
)
){
// It is an overlapping event, so we reject it.
return calendarApi.unselect();
}
});
alert('All good here to create the event.');
//extra event creation code to fire here.
}