Adding second values
Adding a number of seconds to a Date value, for example to add 5 minutes:
Date.now.addingTimeInterval(5 * 60) Date.now + (5 * 60)
This should be only used for short durations; it might not do what you expect for example when adding day intervals with leap days in between; also the computation of the seconds is pretty unreadable and should be avoided.
The Calendar class has an API to perform date calculations:
Calendar.current.date(byAdding: .minute, value: 5, to: Date.now)
It might be handy to define an extension that allows to perform date calculations directly on date values: