Why does NSLocale.current.identifier include currency on macOS?

Question

If I request the current locales identifier on iOS, it returns just the identifier string:

let identifier = NSLocale.current.identifier // en_GB

However, on macOS 10.12.2 it also returns the currency:

let identifier = NSLocale.current.identifier // en_GB@currency=GBP

Is this a bug or expected behaviour?

Answer 1

I think the best option for me here is to generate the code myself. To help with this I have created an extension on Locale:

extension Locale {
    var iso3166code: String {
        guard
            let language = languageCode,
            let region = regionCode
            else { return "en-US" }
        return "\(language)-\(region)"
    }
}

While this is accurate enough for my purposes, you should probably ensure it returns expected values for your project.