Fullcalendar: Set event duration (duration stored in database)

I am currently building an Angular webapp for managing appointments with Fullcalendar. I can display entries from the database and also push them into specific times in the FC calendar.

The problem is that for an event from the database I always specify how long an appointment must go at least, maximum.

Event 1 must go maximum 60 minutes, so the event must not be increased or my move always 60 minutes.

Event 2 must last a maximum of 15 minutes, so the event must not be extended or my postponement must always be 15 minutes.

Event 3 must last a maximum of 45 minutes, so the event must not be increased or my postponement must always be 45 minutes.

Currently an event always lasts 60 minutes. I can’t define the duration in the eventobjects.

Event object from a fullcalendar object tried to manipulate with slotduration, read documentation and tried other solutions.