SwiftUI - UserDefaults array of strings error

Question

I have a problem when trying to save array of strings into the UserDefaults. I have a simple ObservableObject with one property:

class AppManagerModel: ObservableObject {
    @Published var userData = UserDefaults.standard.array(forKey: "userData") as? [String] ?? [String]()
}

Then when i try to update that data from the view

UserDefaults.standard.set(appManagerModel.userData.append("Test"), forKey: "userData")

I get the following error- "Attempt to insert non-property list object () for key userData"

Answer 1

Array.append returns Void . You need to append to the array then set.

class AppManagerModel: ObservableObject {
    @Published var userData = UserDefaults.standard.array(forKey: "userData") as? [String] ?? [String]()
    
    func addUserData(_ data: String) {
        userData.append(data)
        UserDefaults.standard.set(userData, forKey: "userData")
    }
}

Keep your persistence logic hidden in AppManagerModel rather than putting it in your View.