Step 2

redux-reducers.html

<script src="../../node_modules/redux/dist/redux.min.js"></script>

<script>
	(() => {
		const initialState = {
			todos: [
				{text: 'Buy Veggies'},
				{text: 'Buy Fruits'},
				{text: 'Buy Pizza'},
			],
		};

		const todoReducer = (state, action) => {
			if (!state) {
				return initialState;
			}
	
			let todos;
	
			switch (action.type) {
				case 'ADD_TODO':
					todos = state.todos.slice(0);
					todos.push(action.todo);
					return Object.assign({}, state, {todos: todos});
	
				case 'REMOVE_TODO':
					todos = state.todos.slice(0);
					todos.splice(todos.indexOf(action.todo), 1);
					return Object.assign({}, state, {todos: todos});
				default:
					return state;
			}
		};

		App = window.App || {};

		App.rootReducer = Redux.combineReducers({
			todo: todoReducer,
			// Another reducer ...
		});
	})();
</script>