ContentView.swift

struct ContentView: View {

  @State private var newTodo = ""
  @State private var allTodos: [TodoItem] = []

  var body: some View {
    NavigationView {
      VStack {
        HStack {
          TextField("Add todo...", text: $newTodo)
            .textFieldStyle(RoundedBorderTextFieldStyle())

          Button(action: {
            guard !self.newTodo.isEmpty else { return }
            self.allTodos.append(TodoItem(todo: self.newTodo))
            self.newTodo = ""
          }) {
            Image(systemName: "plus")
          }
          .padding(.leading, 5)
        }.padding()
      }
      .navigationBarTitle("Todos")
    }
  }
}