Swift 3: Date <-> ISO 8601 String conversion

Date+ISO8601.swift

extension Date {
    static func ISOStringFromDate(date: Date) -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
        dateFormatter.timeZone = TimeZone(abbreviation: "GMT")
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS"
        
        return dateFormatter.string(from: date).appending("Z")
    }
    
    static func dateFromISOString(string: String) -> Date? {
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
        dateFormatter.timeZone = TimeZone.autoupdatingCurrent
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
        
        return dateFormatter.date(from: string)
    }
}

Not really sure about the Locale to use whether it's sufficiently generalized. Any suggestions?

Thanks it work :)

removed line #5
dateFormatter.timeZone = TimeZone(abbreviation: "GMT")

created this function below with your's to get the local time in Date() format

func setLocalTime(date: Date) -> Date {
let date = Date.dateFromISOString(string: Date.ISOStringFromDate(date: date))!
return date
}

It works for me, congratulations 💪