Locale+Hishma.swift

/// The Locale for a currency code.
///
/// The returned Locale may only contain currency information.
///
/// - Parameter currencyCode: An ISO currency code. See `Locale.commonISOCurrencyCodes` for a list of supported currency codes.
/// - Returns: The Locale corresponding to the currency code, or nil if its not a vakid currency code.
static func localeFrom(currencyCode: String) -> Locale? {
    // Make sure the currency code is supported
    guard self.commonISOCurrencyCodes.contains(currencyCode) else { return nil }

    // If this is the same currency code as the users current locale, return the current locale since
    //  it is more complete and will allow our currency formatter to  correctly display the correct
    //  optional currency symbol as appropriate (E.G. '$' instead of 'US$'.
    guard Locale.current.currencyCode != currencyCode else { return Locale.current }

    let localeComponents = [NSLocale.Key.currencyCode.rawValue: currencyCode]
    let localeIdentifier = Locale.identifier(fromComponents: localeComponents)
    return Locale(identifier: localeIdentifier)
}

If anyone need to use this code on Linux (my app was crushing because NSLocale), the localeComponent constant can be initialize like this:
let localeComponents = Locale.identifier(fromComponents: ["currency": "(currencyCode)"])
return Locale(identifier: localeIdentifier.uppercased())