todolist-redux.js

const { createStore, combineReducers } = Redux;

// ACTIONS CONST
const ADD_TODO = 'ADD_TODO';
const TOGGLE_TODO = 'TOGGLE_TODO';
const DELETE_TODO = 'DELETE_TODO';
const SET_VISIBILITY_FILTER = 'SET_VISIBILITY_FILTER';

// ACTIONS CREATOR
// TODOLIST AC
let nextTodoId = 0;

const addTodo = text => {
  const action = {
  	type: ADD_TODO,
  	title: text,
    id: nextTodoId++
	};
	return action;
};

const toggleTodo = id => {
  const action = {
    type: TOGGLE_TODO,
    id: id
  }
  return action;
};

const deleteTodo = id => {
	const action = {
  	type: DELETE_TODO,
    id: id
  }
  return action;
};

// FILTER AC
const setVisibilityFilter = filter => {
	return {
    type: SET_VISIBILITY_FILTER,
    filter: filter
  }
}

// REDUCERS
const initialState = []; 

function todolistReducer(state = [] /*initialState*/, action) {  
	switch(action.type) {
    case 'ADD_TODO':
      // create a copy of the state, and add the new todo
      return state.concat({
      	title: action.title,
        id: action.id,
        done: false
      })
    case 'TOGGLE_TODO':
      return state.map(todo => {
      	if (todo.id == action.id) {
          //return {...todo,done: !todo.done} // ES2015
        	return Object.assign({}, todo, {
          	done: !todo.done
          })
        }
        return todo
      }
      );
    case 'DELETE_TODO':
      return state.filter(todo => todo.id!=action.id)    
    default:
      return state;
  }
};

function visibilityFilterReducer(state = 'ALL', action){
  console.log(action.type) 
	switch(action.type){
    case 'SET_VISIBILITY_FILTER':
      return action.filter;
    default:
      return state;
  }
}

const reducer = combineReducers({
	todolist : todolistReducer,
  visibilityFilter : visibilityFilterReducer
})

// STORE
const store = Redux.createStore(reducer)//(todolistReducer);

// TEST
store.dispatch(addTodo("Preparare la lezione"));
store.dispatch(addTodo("Comprare regali"));
store.dispatch(addTodo("Andare in vacanza"));
store.getState();
store.dispatch(toggleTodo(2));
store.dispatch(setVisibilityFilter("ACTIVE"));
store.getState();
store.dispatch(deleteTodo(1));
store.getState();