Formatting dates in the user's locale using DateFormatter in Swift

Working with dates is hard, there is no doubt about that. And formatting dates properly for every user of your app is no easier (if you want to do everything manually). Luckily, the system can help us.

For example, in the US one would write "October 15" while in The Netherlands we write 15 oktober.

Note that the order of the date and the month is different, the spelling of the month is different and the capitalization is different too.

The DateFormatter in iOS will handle a lot of this for you. For example, if you'd use the following code on a device that uses nl as its locale you would see the output that I added to this snippet as a comment:

let now = Date()
let formatter = DateFormatter()
formatter.dateFormat = "dd MMMM"
formatter.string(from: now) // 15 oktober

The output of this code is spot on. Exactly what we need and it matches the specified date format perfectly. If you'd run the same code on a device that uses en_us as its locale the output would be 15 October.

The date formatter got the spelling and capitalization right but the date and month are in the wrong order.

You can fix this by using setLocalizedDateFormatFromTemplate on your date formatter instead of assigning its dateFormat directly. Let's look at an example that runs on a device with nl as its locale again:

let now = Date()
let formatter = DateFormatter()
formatter.setLocalizedDateFormatFromTemplate("dd MMMM")
formatter.string(from: now) // 15 oktober

That still works, perfect. If you'd run this code on an en_us device the output would be October 15. Exactly what we need.

If you want to play around with setLocalizedDateFormatFromTemplate in a Playground you can give it a go with the following code that uses a date formatter in different locales:

import Foundation

let now = Date()
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_us")
formatter.setLocalizedDateFormatFromTemplate("dd MMMM")
formatter.string(from: now) // October 15

formatter.locale = Locale(identifier: "nl")
formatter.setLocalizedDateFormatFromTemplate("dd MMMM")
formatter.string(from: now) // 15 oktober

If you have questions about this Quick Tip, or if you want to reach out to me for other reasons then don't hesitate to send me a message on Twitter.

It's a good thing that Swift and Foundation can handle these kinds of