struct ContentView: View {
   @Environment(ApplicationData.self) private var appData
   @State private var searchTerm: String = ""

   var body: some View {
      NavigationStack {
         List(appData.filteredItems) { book in
            CellBook(book: book)
         }.navigationTitle(Text("Books"))
      }
      .searchable(text: $searchTerm, prompt: Text("Insert title"))
      .onChange(of: searchTerm, initial: false) { old, value in
         let search = value.trimmingCharacters(in: .whitespaces)
         appData.filterValues(search: search)
      }
   }
}