CodableArchive.swift

import Foundation
  
struct Person: Codable {
    let name: String
}


let person = Person(name: "Paul")

if #available(macOS 10.12, *) {
    let filePath = URL(fileURLWithPath: "Archiving File")

    let archiver = NSKeyedArchiver()
    try archiver.encodeEncodable(person, forKey: NSKeyedArchiveRootObjectKey)
    try archiver.encodedData.write(to: filePath)
    //archiver.finishEncoding()    // this is unnecessary, .encodedData calls this implicitly


    // attempt to read the thing back
    let data = try Data(contentsOf: filePath)
    let unarchiver = NSKeyedUnarchiver(forReadingWith: data)

    //// .decodeDecodable(...) works, too..., but it does not throw,
    //// it sets .error
    ////if let someone = unarchiver.decodeDecodable(Person.self, forKey: NSKeyedArchiveRootObjectKey) {
    if let someone = try unarchiver.decodeTopLevelDecodable(Person.self, forKey: NSKeyedArchiveRootObjectKey) {
        print("Paul is resurrected...")
        dump(someone)
    } else {
        print("Unable to read person back, Paul is gone forever :(")
    }
    unarchiver.finishDecoding()    // notify delegate decode is done
} else {
    print("Your macOS is too old to run this thing, must be at least ver. 10.12")
}