How can I parse / create a date time stamp formatted with fractional seconds UTC timezone (ISO 8601, RFC 3339) in Swift?

Question

How to generate a date time stamp, using the format standards for ISO 8601 and RFC 3339?

The goal is a string that looks like this:

\"2015-01-01T00:0         


        

Answer 1

Without some manual String masks or TimeFormatters

import Foundation

struct DateISO: Codable {
    var date: Date
}

extension Date{
    var isoString: String {
        let encoder = JSONEncoder()
        encoder.dateEncodingStrategy = .iso8601
        guard let data = try? encoder.encode(DateISO(date: self)),
        let json = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as?  [String: String]
            else { return "" }
        return json?.first?.value ?? ""
    }
}

let dateString = Date().isoString