CodableUserDefaultsBacked.swift

@propertyWrapper 
struct CodableUserDefaultsBacked<T: Codable> {
    let key: String
    let defaultValue: T
    var storage: UserDefaults = .standard

    var wrappedValue: T {
        get {
            return CodableStorageHelper<T>.getValueFor(key: key, storage: storage) ?? defaultValue
        }
        set {
            if let optional = newValue as? AnyOptional,
                optional.isNil {
                storage.removeObject(forKey: key)
            } else {
                CodableStorageHelper<T>.setValue(newValue,
                                                 key: key,
                                                 storage: storage)
            }
        }
    }
}




// UserDefaults Generic Helper Storage
// to save Codable(custom object) in only STANDARD defaults
enum CodableStorageHelper<T: Codable> {
    static func setValue(_ value: T,
                         key: String,
                         storage: UserDefaults = .standard) {
        // Convert newValue to data
        let data = try? JSONEncoder().encode(value)

        // Set value to UserDefaults
        storage.set(data, forKey: key)
        storage.synchronize()
    }

    static func getValueFor(key: String,
                            storage: UserDefaults = .standard) -> T? {
        // Read value from UserDefaults
        guard let data = storage.object(forKey: key) as? Data else {
            // Return defaultValue when no data in UserDefaults
            return nil
        }

        // Convert data to the desire data type
        let value = try? JSONDecoder().decode(T.self, from: data)
        return value ?? nil
    }
}