UserDefault property wrapper

UserDefault-propertywrapper.swift

import Foundation

@propertyDelegate
public struct UserDefault<ValueType> {
	
	public let key: String
	public let defaults: UserDefaults
	public let defaultValue: () -> ValueType
	
	init(key: String, defaultValue: @autoclosure @escaping () -> ValueType, defaults: UserDefaults = .standard) {
		self.key = key
		self.defaultValue = defaultValue
		self.defaults = defaults
	}
	
	public var value: ValueType {
		get {
			if let userDefaultsObject = userDefaultsGet() {
				return userDefaultsObject
			}
			let defValue = defaultValue()
			userDefaultsSet(defValue)
			return defValue
		}
		set { userDefaultsSet(newValue) }
	}
	
	private func userDefaultsGet() -> ValueType? {
		return self.defaults.object(forKey: self.key) as? ValueType
	}
	private func userDefaultsSet(_ newValue: ValueType) {
		self.defaults.set(newValue, forKey: self.key)
	}
}