property wrappers in Swift

Usage

Declaration

@propertyWrapper struct UserDefaultsBacked<Value> {
    let key: String
    var storage: UserDefaults = .standard
 
    var wrappedValue: Value? {
        get { storage.value(forKey: key) as? Value }
        set { storage.setValue(newValue, forKey: key) }
    }
}

Callsite

struct SettingsViewModel {
    @UserDefaultsBacked<Bool>(key: "mark-as-read")
    var autoMarkMessagesAsRead
 
    @UserDefaultsBacked<Int>(key: "search-page-size")
    var numberOfSearchResultsPerPage
}

Sources

• Property wrappers in Swift | Swift by Sundell