swift - Conditional property in SwiftUI

Question

How can I add an additional property based on a condition?

With my code below I got the error Cannot assign value of type 'some View' (result of 'Self.overlay(_:alignment:)') to type 'some View' (result of 'Self.onTapGesture(count:perform:)')

import SwiftUI

struct ConditionalProperty: View {
    @State var overlay: Bool
    var body: some View {
        var view = Image(systemName: "photo")
            .resizable()
            .onTapGesture(count: 2, perform: self.tap)
        if self.overlay {
            view = view.overlay(Circle().foregroundColor(Color.red))
        }
        return view
    }

    func tap() {
        // ...
    }
}

Answer 1

Thanks to this post I found an option with a very simple interface:

Text("Hello")
    .if(shouldBeRed) { $0.foregroundColor(.red) }

Enabled by this extension:

extension View {
    @ViewBuilder
    func `if`<Transform: View>(_ condition: Bool, transform: (Self) -> Transform) -> some View {
        if condition { transform(self) }
        else { self }
    }
}

Here is a great blog post with additional tips for conditional modifiers: https://fivestars.blog/swiftui/conditional-modifiers.html