These docs are for an old release. Info on upgrading to version 2/3
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clientEvents 1.3

Retrieves events that FullCalendar has in memory.

.fullCalendar( ‘clientEvents’ [, idOrFilter ] ) -> Array

This method will return an array of Event Objects that FullCalendar has stored in client-side memory.

If idOrFilter is omitted, all events will be returned.

If idOrFilter is an ID, all events with the same ID will be returned.

idOrFilter may also be a filter function that accepts one Event Object argument and returns true if it should be included in the result set.

In versions 1.2 and 1.2.1, this option was known as getEventsByID