SwiftUI Property Wrapper Binding

ProductView.swift

struct ProductView: View {
   @State private var isFavorite: Bool = false

   var body: some View {
	// ... 
     FavButton(isFavorite: $isFavorite) // Pass a binding.
   }
}

struct FavButton: View {
   @Binding var isFavorite: Bool

   var body: some View {
       Button(action: {
          isFavorite.toggle()
       }, label: {
          Image(isFavorite ? "Filled_Heart" : "Heart")
       })
   }
}