NSDate returning wrong date in Swift

Question

Today is Feb 1 of 2016 and I just opened up my working app to continue my work and this shocks me.

It is a collection view of date, I didn't notice anything wrong during January because it hasn't been a month.

Here's the code,

func dF(someDate:NSDate) -> (String){
let monthFormat = NSDateFormatter()
let dayFormat = NSDateFormatter()
monthFormat.dateFormat = "MMM"
dayFormat.dateFormat = "D"

let aMonth = monthFormat.stringFromDate(someDate)
let aDay = dayFormat.stringFromDate(someDate)

//concatenate strings
let conString = aMonth + " " + aDay

return (conString)
}


//from today to 7th day, to be used in ScrollView
let day1 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: 0, toDate: NSDate(), options: [])
let day2 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -1, toDate: NSDate(), options: [])
let day3 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -2, toDate: NSDate(), options: [])
let day4 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -3, toDate: NSDate(), options: [])
let day5 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -4, toDate: NSDate(), options: [])
let day6 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -5, toDate: NSDate(), options: [])
let day7 = NSCalendar.currentCalendar().dateByAddingUnit(.Day, value: -6, toDate: NSDate(), options: [])
let titles = [dF(day1!), dF(day2!), dF(day3!), dF(day4!), dF(day5!), dF(day6!), dF(day7!)]

I'm expecting day1 to pass the current date to function dF and format it.

So I ran some checks to make sure I've got the correct date Current time: Feb 1, 2016, 1:08am in my time zone

print(day1)
print(day2)
print(ddd)

Here's the result from console:

Optional(2016-01-31 17:08:47 +0000)

Optional(2016-01-30 17:08:47 +0000)

Feb 32

I'm suspecting my NSDateComponent isn't setup correctly/on par with local time zone. Any ideas?

Answer 1

1. You are using the wrong specifier for the day of the month.
2. You are creating your date string the hardest way possible.

Try this:

Swift 3/4:

func dF(_ someDate: Date) -> String {
    let format = DateFormatter()
    format.dateFormat = "MMM d"
    // For a more localized format, use the following instead:
    // format.setLocalizedDateFormatFromTemplate("MMMd")        

    let conString = format.string(from: someDate)

    return conString
}

Old Swift 2 answer: func dF(someDate:NSDate) -> (String){ let format = NSDateFormatter() format.dateFormat = "MMM d"

    let conString = format.stringFromDate(someDate)

    return (conString)
}