Swift 3/4/5:
Calendar.current.isDateInToday(yourDate)
Calendar.current.isDateInYesterday(yourDate)
Calendar.current.isDateInTomorrow(yourDate)
Additionally:
Calendar.current.isDateInWeekend(yourDate)
Note that for some countries weekend may be different than Saturday-Sunday, it depends on the calendar.
You can also use autoupdatingCurrent instead of current calendar, which will track user updates. You use it the same way:
Calendar.autoupdatingCurrent.isDateInToday(yourDate)
Calendar is a type alias for the NSCalendar.