Save unique String Array With #AppStorage - macos

Question

In the following example I am saving a String with #AppStorage:
struct ContentView: View {
#AppStorage("text") private var text = ""
var body: some View {
Button("Append text: \(text)") {
text.append("APPEND")
}
}
}
But I want to save a unique String array, something like this:
#AppStorage("text") #State private var customer = [CustomerId]()
//
struct CustomerId: Identifiable {
let id = UUID()
var number: String
init(_ number: String) {
self.number = number
}
//
Button {
customer
.append(CustomerId("New Id"))
}

Answer 1

It's highly recommended to move the entire code to modify the model into an extra class called view model.
The #AppStorage property wrapper reads and writes a JSON string.
The #Published property wrapper updates the view.
In the init method the saved JSON string is decoded to [CustomerId].
The method appendCustomer appends the items, encodes the array to JSON and writes it to disk.
class ViewModel : ObservableObject {
#AppStorage("text") var text = ""
#Published var customer = [CustomerId]()
init() {
customer = (try? JSONDecoder().decode([CustomerId].self, from: Data(text.utf8))) ?? []
}
func appendCustomer(_ sustomerId : CustomerId) {
customer.append(sustomerId)
guard let data = try? JSONEncoder().encode(customer),
let string = String(data: data, encoding: .utf8) else { return }
text = string
}
}
struct ContentView : View {
#StateObject private var model = ViewModel()
#State private var counter = 0
var body: some View {
VStack{
ForEach(model.customer) { item in
Text(item.number)
}
Button("Append text: New Id \(counter)") {
model.appendCustomer(CustomerId(number: "New Id \(counter)"))
counter += 1
}
}
}
}