z2015

文／guog（簡書作者）
原文鏈接：http://www.jianshu.com/p/95a269951a1b#
著作權歸作者所有，轉載請聯繫作者獲得授權，並標註“簡書作者”。

robocopy empty_dir will_delete_dir /purge

z2015

const counter = (state = 0, action) => {

  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
      
    case 'DECREMENT':
      return state - 1;
      
    default:

z2015

const counter = (state = 0, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    case 'DECREMENT':
      return state - 1;
    default:
      return state;
  }
}

z2015

const counter = (state = 0, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    case 'DECREMENT':
      return state - 1;
    default:
      return state;
  }
};

z2015

const counter = (state = 0, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    case 'DECREMENT':
      return state - 1;
    default:
      return state;
  }
};

z2015

const addCounter = (list) => {
  return [...list,0]
};

const removeCounter = (list, index) => {
  return [
    ...list.slice(0, index),
    ...list.slice(index + 1)
  ];
};

z2015

const toggleTodo = (todo) => {
  return {
    ...todo,
    completed: !todo.completed
  }
};

const testToggleTodo =()=> {
  const todoBefore = {
    id: 0,

z2015

const todos = (state=[], action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return [
        ...state,
        {
          id: action.id,
          text: action.text,
          completed: false
        }

z2015

const todos = (state=[], action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return [
        ...state,
        {
          id: action.id,
          text: action.text,
          completed: false
        }

z2015

const todo = (state, action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return {
        id: action.id,
          text: action.text,
          completed: false
      };
    
    case 'TOGGLE_TODO':