Using SwiftData I have a very basic model with an optional date:

import SwiftData

@Model
class Item {
    var name: String
    var date: Date? = nil

    init(name: String, date: Date) {
        self.name = name
        self.date = date
    }
}

I'm working on the Add view to insert data into that model and no matter what I've tried so far, I get a variety of different errors around the date field. I'm fairly certain I have to hide the date picker, since I don't think I can have it displayed with an empty value. But even then, since I'm binding data to the field, I get this error: Cannot convert value of type 'Binding<Date?>' to expected argument type 'Binding<Date>'

    @State private var newItem = Item(name: "", date: Date())

    var body: some View {

        List{
            Section("Add item"){
                TextField("Enter Name", text: $newItem.name)

                HStack{
                    Text("Select Date")
                    Spacer()
                    Image(systemName: "calendar.badge.plus")
                    if let date = $newItem.date {
                        DatePicker("Date", selection: date)
                    }
                }

I've tried a variety of alternates in the @State declaration around date with nil but those generate their own errors that 'nil' cannot be assigned to type 'Date.Type'

It seems like it's impossible to have a date field that is optional but I've seen other apps pull it off, I simply have no idea how. Any suggestions?

The initializer in your Item class requires a Date as a parameter, rather than a Date?. If you change that, does that help with your problem?

I think it does help, because things are starting to look right but I'm not quite all the way there yet.

I updated the init in the model

@Model
class Item {
    var name: String
    var date: Date? = nil

    init(name: String, date: Date?) {
        self.name = name
        self.date = date
    }
}

And the State to align (I think): @State private var newItem = Item(name: "", date: Date?.none)

But I'm still getting the binding error at the date picker, which I haven't changed: Cannot convert value of type 'Binding<Date?>' to expected argument type 'Binding<Date>'

This is the complete demo project

struct ContentView: View {
    // Added to make list work for testing
    @State private var items = [Item]()

    // Temporary properties to enter data
    @State private var name = ""
    @State private var date = Date.now

    // A property to show DataPicker if date is required
    @State private var showingDatePicker = false

    var body: some View {
        List{
            Section("Add item"){
                TextField("Enter Name", text: $name)

                if showingDatePicker {
                    HStack{
                        Image(systemName: "calendar.badge.plus")

                        DatePicker("Date", selection: $date, displayedComponents: .date)
                    }
                } else {
                    Button {
                        withAnimation {
                            showingDatePicker.toggle()
                        }
                    } label: {
                        Label("Select Date", systemImage: "calendar.badge.plus")
                    }
                }

                Button("Add", action: save)
            }

            // List to show that you adding Items with and with Date
            Section {
                ForEach(items) { item in
                    HStack {
                        Text(item.name)
                        Spacer()
                        if let date = item.date {
                            Text(date, style: .date)
                        }
                    }
                }
            }
        }
    }

    func save() {
        let item: Item

        if showingDatePicker {
            item = Item(name: name, date: date)
        } else {
            item = Item(name: name)
        }

        // Add to array but you could save to SwiftData
        items.append(item)
    }
}

#Preview {
    ContentView()
}

class Item: Identifiable {
    var id = UUID() // <- Added to make list work for testing
    var name: String
    var date: Date?

    init(name: String, date: Date? = nil) {
        self.name = name
        self.date = date
    }
}

Thank you so much! Unfortunatley, I do really need it to be an optional Date for other parts of the app to work correctly. This is unbelievably helpful.