Hello,

the new XCode 15 comes with macros, and a prominent one is the #Preview {}

However, in the past, I could do this

struct NetworkButton_Preview: PreviewProvider {
    static var previews: some View {
        @State var b:String = "Success test"
        @State var c:String = "Nope test"
        VStack{
            NetworkButton(selectedTab: $b)
            NetworkButton(selectedTab: $c)
        }
    }
}

where selectedTab is @Binding var selectedTab: String

But the same with the new syntax, will not work.

#Preview {
    @State var b:String = "Success test"
    @State var c:String = "Nope test"
    VStack{
        NetworkButton(selectedTab: $b)
        NetworkButton(selectedTab: $c)
    }
}

I've looked through the WWDC video on it but couldn't find the answer. For now, I've reverted to using the old syntax pre-macros.

Is there a way?

Not sure if this will work for your use case ?

#Preview {
  @State var toggleA = false
  @State var toggleB = true
    return VStack {
        Toggle("A", isOn: $toggleA)
        Toggle("B", isOn: $toggleB)
    }
}

No, no that's not it. That won't compile.

Cannot use explicit 'return' statement in the body of result builder 'ViewBuilder'

The solution to this is you need to return your VStack from the trailing closure.

#Preview {
    @State var b:String = "Success test"
    @State var c:String = "Nope test"
    return VStack{
        NetworkButton(selectedTab: $b)
        NetworkButton(selectedTab: $c)
    }
}

The body of the #Preview is a closure that returns a View. So given how closures work by adding the State variables you can no longer us the shorthand implicit return. You must explicitly return the view.

@freestanding(declaration)
macro Preview(
    _ name: String? = nil,
    body: @escaping @MainActor () -> View
)

https://developer.apple.com/documentation/swiftui/preview(_:body:)/