Initialize @StateObject with a parameter in SwiftUI

Here is a demo of solution. Tested with Xcode 12b.

class MyObject: ObservableObject {
    @Published var id: Int
    init(id: Int) {
        self.id = id
    }
}

struct MyView: View {
    @StateObject private var object: MyObject
    init(id: Int = 1) {
        _object = StateObject(wrappedValue: MyObject(id: id))
    }

    var body: some View {
        Text("Test: \(object.id)")
    }
}

backup