A good example of how we can use property wrappers in Swift 5 to make working with UserDefaults so much more cleaner. We can define a 'UserDefaultsConfig' type to contain all the values we want to persist making it easier to read!

UserDefault.swift

@propertyWrapper
struct UserDefault<T> {
    let key: String
    let defaultValue: T

    init(_ key: String, defaultValue: T) {
        self.key = key
        self.defaultValue = defaultValue
    }

    var wrappedValue: T {
        get {
            return UserDefaults.standard.object(forKey: key) as? T ?? defaultValue
        }
        set {
            UserDefaults.standard.set(newValue, forKey: key)
        }
    }
}

struct UserDefaultsConfig {
    @UserDefault("has_onboarded", defaultValue: false)
    static var userHasOnboarded: Bool

    @UserDefault("app_theme", defaultValue: "main_theme")
    static var appTheme: String
}



UserDefaultsConfig.userHasOnboarded = false
print(UserDefaultsConfig.userHasOnboarded) // Prints: false

UserDefaultsConfig.appTheme = "pro_theme"
print(UserDefaultsConfig.appTheme) // Prints: "pro_theme"