<vuex第一弹>vuex之state和Mutation（前端网备份）

state为访问状态对象
Mutation为触发状态各人理解，这里做的是一些全局改变样式这种类似的操作
通过vue入口文件main.js里面开始
main.js
import store from './store/index'
new Vue({
el: '#app',
router,
store,
render: h => h(App)
})
写vuex的层
store/index.js

import Vue from 'vue'
import Vuex from 'vuex'
import state from './state'
import mutations from './mutation'
Vue.use(Vuex);
export default new Vuex.Store({
    state,
    mutations
})

store/state.js

const state = {
    count : 44,
    bColor:"orange"
}
export default  state;

store/mutation.js

const mutations = {
    jian(state){
        state.count--
    },
    jia(state,n){
        state.count+=n.a
    },
    changeColor(state){
        if(state.bColor == "orange"){
            state.bColor = "blue"
        }else{
            state.bColor = "orange"
        }
    }
}
export default mutations

调用vuex的组件层

<template>
  <div class="wrapper">
    我是list1_son
    {{$store.state.count}}-{{count}}
     <button @click="$store.commit('jia',num)">+</button>  
     <!-- <button @click="jia(num)">+</button>  -->
     <button @click="changeColor(bColor)">改变背景颜色</button>
     <div :style="{background:bColor}" class="text_bc">123</div>
     <button @click="jia(num)">+</button> 
    <button @click="jian">-</button> 
  </div>
</template>

<script>
import { mapState, mapMutations } from "vuex";
export default {
  components: {},
  props: {},
  data() {
    return {
        num:{a:2},
    };
  },
  watch: {},
  //几种写法形式
  //   computed:{
  //       count(){
  //           return this.$store.state.count - 1
  //       }
  //   },
//   computed: mapState({
//     count: state => state.count + this.num
//   }),
//mapState简写在computed里;mapMutations简写在methods里
 computed: {
     ...mapState({
        count: state => state.count + 2,
        bColor: state => state.bColor
    }),

 },
  methods: {
    //不简写的方法，直接在这里定义方法，在里面去传参
    //   jia(){
    //       let num = this.num;
    //       this.$store.commit('jia',num) 
    //   },
    //简写的方法必须在上面的@click="jia(num)"动态传参,目前只实现了这种形式
      ...mapMutations({
            jian: 'jian',
            jia:'jia',
            changeColor:'changeColor'
        }),
  },
  created() {
  },
  mounted() {
    console.log(this.$store.state.count);
  }
};
</script>
<style  scoped>
.wrapper {
  color: grey;
}
.text_bc{
    background: orange;
    width:100px;
    height:100px;
    display: flex;
    align-items: center;
    text-align: center;
    justify-content: center
}
</style>