Creating a shopping cart application with Cubit

Cubit is a slight variant of BLoC. To create a shopping cart application using Cubit, create a new Flutter application named cart_cubit and copy item.dart and cart_state.dart from the previous section's application into your lib folder. Also, add dependencies for the equatable and flutter_bloc packages from pub.dev. Then, follow these steps:

1. Replace the contents of the cart_state.dart file with the following code:

   import 'package:equatable/equatable.dart';
   import 'item.dart';
   class CartState extends Equatable {
     @override
     List<Object?> get props => [];
   }
   class CartListState extends CartState {
     final List<Item> cart;
     CartListState({this.cart = const []});
     @override
     List<Object?> get props => [this.cart];
   }
   class CartUpdatingState extends CartState {}

2. Create a new file named cart_cubit.dart and add the following...