Ubiquitous.swift

@propertyWrapper
struct Ubiquitous<T> {
    private var key: String
    private var defaultValue: T
    private var store: NSUbiquitousKeyValueStore
    
    init(key: String, defaultValue: T, store: NSUbiquitousKeyValueStore = .default) {
        self.key = key
        self.defaultValue = defaultValue
        self.store = store
    }
    
    var wrappedValue: T {
        get {
            return store.object(forKey: key) as? T ?? defaultValue
        }
        set {
            store.set(newValue, forKey: key)
        }
    }
}

// Usage
@Ubiquitous(key: "collectionscreated", defaultValue: 0)
var collectionsCreated: Int