How to get start and end of the week in swift?

Question

How to get start and end of the week in swift ? this is my code

extension Date {
    var startOfWeek: Date? {
        let gregorian = Calendar(identifier: .gregorian)
        guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
        return gregorian.date(byAdding: .day, value: 1, to: sunday)
    }

    var endOfWeek: Date? {
        let gregorian = Calendar(identifier: .gregorian)
        guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
        return gregorian.date(byAdding: .day, value: 7, to: sunday)
    }
}

i am calling like this

let startWeek = Date().startOfWeek
let endWeek = Date().endOfWeek
print(startWeek!)
print(endWeek!)
var dateFormat1 = DateFormatter()
dateFormat1.dateFormat = "dd-MM-yy"
let startWeek2 = dateFormat1.string(from: startWeek!)
var dateFormat12 = DateFormatter()
dateFormat12.dateFormat = "dd-MM-yy"
let endWeek2 = dateFormat12.string(from: endWeek!)
print(startWeek2)
print(endWeek2)

and output

2017-09-24 18:30:00 +0000
2017-09-30 18:30:00 +0000
25-09-17
01-10-17

What is wrong? Please include a description of the expected behaviour and the actual behaviour as well, don't just show your current output... — Dávid Pásztor, Sep 25 '17 at 10:14
see in my output, after adding date formatter dates getting increse from 24-09-2017 to 25-09-2017 — Ram, Sep 25 '17 at 10:17

score 3 · Accepted Answer · answered Sep 25 '17 at 10:35

Your code is working perfectly fine. If you would run your code in a Playground, you could see the actual Date objects rather than there String representations. Even if you don't specify a DateFormatter, under the hood, when doing print(Date()), Swift uses a DateFormatter to print Date objects and hence that value will be a relative time instead of the absolute point in time provided by the Date object.

In a Playground you can see that the actual startOfWeek is "Sep 25, 2017 at 12:00 AM", while the endOfWeek is "Oct 1, 2017 at 12:00 AM", which are the correct values for the current week.

Don't use print(Date()) for checking the correctness of Date objects, since as you can see, it will yield unexpected results due to the underlying DateFormatters used.

How to get start and end of the week in swift?

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