UserDefault property wrapper

UserDefault.swift

/// Example of usage:
/// ```swift
/// @UserDefault("username") var username: String? = nil
/// @UserDefault("maxItems") var maxItems = 100
/// ```
@propertyWrapper
struct UserDefault<T> {
	let defaultValue: T
	let key: String
	private let environment: UserDefaults
	
	var wrappedValue: T {
		get {
			environment.object(forKey: key) as? T ?? defaultValue
		}
		set {
			if case Optional<T>.none = newValue as Any {
				environment.removeObject(forKey: key)
			}
			else {
				environment.set(newValue, forKey: key)
			}
		}
	}
	
	init(wrappedValue: T, _ key: String, environment: UserDefaults = .standard) {
		self.key = key
		self.environment = environment
		self.defaultValue = wrappedValue
	}
}