VueX--- actions→mutations or getters→state 四大金刚

Vuex 

1.安装vuex

npm install  -save vuex

2. 引入 创建store文件夹目录

创建 vuex     指挥公共目录    store【'state','actions','mutations','getters','index'】

3.store  -》index.js  (所有的store下的都引入进去进行声明 )

import Vue from 'vue'
import Vuex from 'vuex'
import state from './state'
import mutations from './mutations'
import actions from './actions'
import getters from './getters'

Vue.use(Vuex)

/* eslint-disable new-cap */

export default new Vuex.Store({
  state,
  mutations,
  actions,
  getters
})

4.在main.js 

/*
入口JS
 */
import Vue from 'vue'
import App from './components/App'
import store from './store'
import './base.css'
/* eslint-disable no-new */

new Vue({
  el: '#app',
  // components:{App},
  // template:'<App/>'
  render: h => h(App),
  store
})

5.在组件儿中使用

　　1.this.$store.dispath('addTodo');

　　2.import {mapActions} from 'vuex'

　　　...mapActions('addTodo')

6.

state     对应的data存放数据对象    state.todos

mutations 操作变更state数据    

[CLEAR_ALL_COMPLETED](state){
      state.todos = state.todos.filter(todo => (!todo.complete))
  }

getters 计算state   计算属性的方法都是i在这里

   totalCount(state){       return state.todos.length    }

actions  触发mutations中的方法     this.$store.dispatch('removeTodo')

/*

组件写  this.$store.dispath('')      调用这里的方法
    接受组件通知触发 mutation调用间接状态的方法的对象
 */

import {ADD_TODO, DELETE_TODO, SELECT_ALL_TODOS, CLEAR_ALL_COMPLETED,RECEIVE_TODOS} from './mutation-types'
import storageUtil from '../utils/storageUtils.js'
export default {
  addTodo ({commit}, todo) {
    commit(ADD_TODO, {todo})
  },
  deleteTodo({commit},index){
      commit(DELETE_TODO,{index})
  },
  selectAllTodos ({commit}, check) {
    commit(SELECT_ALL_TODOS, {check})
  },
  clearALLCompleted({commit}){
      commit(CLEAR_ALL_COMPLETED)
  },
  reqTodos({commit},todos){
      setTimeout(()=>{
          // 读取数据
      const todos = storageUtil.readTodos()
          // 提交数据
        commit(RECEIVE_TODOS,todos)
      },1000)
  }
}