Encode Codable instances into UserDefaults. Use only with small instances.

UserDefaults+Codable.swift

//
//  UserDefaults+Codable.swift
//  Converter UltraLight
//
//  Created by Brent Royal-Gordon on 8/31/17.
//  Copyright © 2017 Architechies. All rights reserved.
//  MIT-licensed, go nuts with it.
//

import Foundation

extension UserDefaults {
    func encode<T: Encodable>(_ value: T?, forKey key: String) throws {
        let data = try value.map(PropertyListEncoder().encode)
        let any = data.map { try! PropertyListSerialization.propertyList(from: $0, options: [], format: nil) }
        
        set(any, forKey: key)
    }
    
    func decode<T: Decodable>(_ type: T.Type, forKey key: String) throws -> T? {
        let any = object(forKey: key)
        let data = any.map { try! PropertyListSerialization.data(fromPropertyList: $0, format: .binary, options: 0) }
        
        return try data.map { try PropertyListDecoder().decode(type, from: $0) }
    }
}