Xcode – Retrieving data using URLSession and ViewModel

I’m attempting to retrieve data for a user profile, and I’m not sure how to initialize the observable objects in my view model. I see a lot of examples of where an array of objects will be returned, but not one single object.

How can I initialize the profile variable in the view model with a null value before I attempt to fetch the profile data, or should I not use this method for retrieving this data?

Also on a side note, is it best practice to write a common class (like a RestManager class) to handle all API requests and have one method which invokes the URLSession dataTaskPublisher method?

Model:

struct Profile: Codable, Hashable, Identifiable {
    var id: UUID
    var address: String
    var city: String
    var emailAddress: String
    var firstName: String
    var lastName: String
    var smsNumber: String
    var state: String
    var userBio: String
    var username: String
    var zipCode: Int
}

ViewModel:

class ProfileViewModel: ObservableObject {
    // Cannot create Profile() as it needs data to be instantiated
    @Published var profile: Profile = Profile()

    init() {
        fetchProfile()
    }

    func fetchProfile() {
        guard let url = URL(string: "https://path/to/api/v1/profiles") else {
            print("Failed to create URL")
            return
        }
        
        let requestData = [
            "username": "testuser"
        ]
        var request = URLRequest(url: url)
        request.setValue("application/json", forHTTPHeaderField: "Accept")
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpMethod = "GET"
        request.httpBody = try? JSONEncoder().encode(requestData)
        
        URLSession.shared.dataTaskPublisher(for: request)
            .tryMap { output in
                guard let response = output.response as? HTTPURLResponse, response.statusCode == 200 else {
                    throw HTTPError.statusCode
                }

                return output.data
            }
            .decode(type: Profile.self, decoder: JSONDecoder())
            .retry(3)
            .replaceError(with: Profile()) // Same issue here - requires data to be instantiated
            .eraseToAnyPublisher()
            .receive(on: DispatchQueue.main)
            .assign(to: &$profile)
    }
}

View:

struct ProfileSummary: View {
    @ObservedObject var viewModel: ProfileViewModel

    var body: some View {
        NavigationView {
            VStack {
                Text(viewModel.profile.firstName)
                Text(viewModel.profile.lastName)
            }
            .navigationTitle("Profile")
            .onAppear {
                viewModel.fetchProfile()
            }
        }
    }
}