SwiftUI - Add a Navigation Bar Button on Condition

Given i have a view like this..

@State var tabIndex: Int = 0
           
 var body: some View {

  TabView(selection: $tabIndex)
  {
   Text("Tab 1").tabItem({
    Image(systemName: "message")
   }).tag(0)           
                
   Text("Tab 2").tabItem({
    Image(systemName: "arkit")
   }).tag(1)             
          
   Text("Tab 3").tabItem({
    Image(systemName: "battery.100")
   }).tag(2)
  }.navigationBarTitle("Tabbed View")
            
 }

This produces a view like this which is what is expected:

to add a navigation button to the bar i can use

 .navigationBarItems(trailing:
  Button(action: {print("Button was tapped")}) {
   Image(systemName: "plus")
    .resizable().frame(width: 20, height: 20)
  })

Which adds the button as expected

Is there any way to only add (or show) the button based on a condition?

if (self.tabIndex == 1){
  show button
}
else {
 don't show button
}

As .navigationBarItems will be deprecated in a future version of iOS it's better to use .toolbar(_:) View Modifier.

.toolbar {
	ToolbarItemGroup(placement: .navigationBarTrailing) {
		if tabIndex == 2 {
            // show button
		}
	}
}

Here is possible approach

.navigationBarItems(trailing: self.tabIndex == 1 ? 
    AnyView(self.trailingButton) : AnyView(EmptyView()))

somewhere below body

var trailingButton: some View {
  Button(action: {print("Button was tapped")}) {
   Image(systemName: "plus")
    .resizable().frame(width: 20, height: 20)
  }
}

If you don't want to use AnyView, you could also use Group or Opacity too.

.navigationBarItems(trailing: Group {
  if self.tabIndex == 1 {
    Button(action: {print("Button was tapped")}) {
     Image(systemName: "plus")
      .resizable().frame(width: 20, height: 20)
    }
  }
})

.navigationBarItems(trailing: 
    Button(action: {print("Button was tapped")}) {
     Image(systemName: "plus")
      .resizable().frame(width: 20, height: 20)
    }.opacity(self.tabIndex == 1 ? 1 : 0)
)

I know this question has an accepted answer and I used it in my own solution but here's what I did:

var doneButton:AnyView {
    if !fromPreferences {
        return AnyView(Button(action: self.doneAction) {
            Text("Done")
        })
    }
    return AnyView(EmptyView())
}

and how I used it in the body:

.navigationBarItems(trailing: doneButton)

thanks @Asperi for the solution!

Here is what worked for me, even when my condition was false which resulted in nothing being returned (the bar item correctly did not show, without errors). I find it a little cleaner than squeezing in a ternary operator.

.navigationBarItems(
	trailing: Button(
		action: {
			print("My Action")
		}
	) {
		if myBool {
			Text("My Button")
		}
	}
)