Property wrapper for `UserDefaults.standard` backed value

UserDefaultsPropertyWrapper.swift

import Foundation

/// Property wrapper for `UserDefaults.standard` backed value
@propertyWrapper
struct UserDefault<Value: UserDefaultsValue> {
    let key: String
    let defaultValue: Value
    let container: UserDefaults

    init(key: String, defaultValue: Value = Value(), container: UserDefaults = .standard) {
        self.key = key
        self.defaultValue = defaultValue
        self.container = container
    }

    var wrappedValue: Value {
        get {
            return container.object(forKey: key) as? Value ?? defaultValue
        }
        set {
            container.set(newValue, forKey: key)
        }
    }
}

protocol UserDefaultsValue {
    init()
}

extension NSData: UserDefaultsValue {}
extension NSString: UserDefaultsValue {}
extension NSNumber: UserDefaultsValue {}
extension NSArray: UserDefaultsValue {}
extension NSDictionary: UserDefaultsValue {}
extension Float: UserDefaultsValue {}
extension Double: UserDefaultsValue {}
extension Int: UserDefaultsValue {}
extension Bool: UserDefaultsValue {}