Swift - Weekday by current location by currentCalendar()

For the Gregorian calendar, the weekday property of NSDateComponents is always 1 for Sunday, 2 for Monday etc.

NSCalendar.currentCalendar().firstWeekday

gives the (index of the) first weekday in the current locale, that could be 1 in USA and 2 in Bulgaria. Therefore

var dayOfWeek = dateComps.weekday + 1 - calendar.firstWeekday
if dayOfWeek <= 0 {
    dayOfWeek += 7
}

is the day of the week according to your locale. As a one-liner:

let dayOfWeek = (dateComps.weekday + 7 - calendar.firstWeekday) % 7 + 1

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Update for Swift 3:

let calendar = Calendar.current
var dayOfWeek = calendar.component(.weekday, from: Date()) + 1 - calendar.firstWeekday
if dayOfWeek <= 0 {
    dayOfWeek += 7
}