vue3.0下如何使用mapState，mapGetters和mapActions

vue2.0中使用mapState及mapActions的方式

// 使用mapState computed:{...mapState({//...})}  methods:{...mapActions(['fnA','fnB'])}

vue3.0中获取state和使用actions的方式

import{computed}from'vue'import{useStore}from'vuex'setup(){const store=useStore();const stateA=computed(()=> store.state.stateA);const stateB=computed(()=> store.state.stateB);const methodA= store.dispatch('methodA',{name:'张三'});}

那如何才能在vue3下使用mapState这些api呢？

答案是封装mapState，mapGetters，mapActions方法。

1、新建useMapper.js

import{ useStore}from'vuex'import{ computed}from'vue'exportfunctionuseStateMapper(mapper, mapFn){const store=useStore();const storeStateFns=mapFn(mapper);const storeState={};     Object.keys(storeStateFns).forEach(fnKey=>{// vuex源码中mapState和mapGetters的方法中使用的是this.$store,所以更改this绑定const fn= storeStateFns[fnKey].bind({ $store: store});         storeState[fnKey]=computed(fn)})return storeState}exportfunctionuseActionMapper(mapper, mapFn){const store=useStore();const storeActionsFns=mapFn(mapper);const storeAction={};      Object.keys(storeActionsFns).forEach(fnKey=>{         storeAction[fnKey]= storeActionsFns[fnKey].bind({ $store: store})})return storeAction}

2、新建useState.js

import{ mapState, createNamespacedHelpers}from'vuex'import{ useStateMapper}from'./useMapper'import{checkType}from'./index'/**  *   * @param {*} moduleName 模块名称  * @param {*} mapper state属性集合 ['name', 'age']  * @returns   */exportfunctionuseState(moduleName, mapper){let mapperFn= mapState;// 如果使用模块化，则使用vuex提供的createNamespacedHelpers方法找到对应模块的mapState方法if(checkType(moduleName)==="[object String]"&& moduleName.length>0){         mapperFn=createNamespacedHelpers(moduleName).mapState}returnuseStateMapper(mapper, mapperFn)}

3、新建useGetters.js

import{ mapGetters, createNamespacedHelpers}from'vuex'import{ useStateMapper}from'./useMapper'import{checkType}from'./index'/**  *   * @param {*} moduleName 模块名称  * @param {*} mapper getters属性集合 ['name', 'age']  * @returns   */exportfunctionuseGetters(moduleName, mapper){let mapperFn= mapGetters;// 如果使用模块化，则使用vuex提供的createNamespacedHelpers方法找到对应模块的mapGetters方法if(checkType(moduleName)==="[object String]"&& moduleName.length>0){         mapperFn=createNamespacedHelpers(moduleName).mapGetters}returnuseStateMapper(mapper, mapperFn)}

4、新建useActions.js

import{ mapActions, createNamespacedHelpers}from'vuex';import{useActionMapper}from'./useMapper'import{checkType}from'./index'/**  *   * @param {*} moduleName 模块名称  * @param {*} mapper 方法名集合 ['fn1', 'fn2']  * @returns   */exportfunctionuseActions(moduleName, mapper){let mapperFn= mapActions;// 如果使用模块化，则使用vuex提供的createNamespacedHelpers方法找到对应模块的mapActions方法if(checkType(moduleName)==="[object String]"&& moduleName.length>0){         mapperFn=createNamespacedHelpers(moduleName).mapActions}returnuseActionMapper(mapper, mapperFn)}

5、页面中使用

<template><divclass="home"><span>姓名：{{name}} 年龄：{{age}} 性别：{{sex}}</span><button @click="changeName">改名</button></div></template><script>// @ is an alias to /srcimport{useState}from'@/utils/useState'import{useActions}from'@/utils/useAction'exportdefault{     name:"home",setup(){const storeState=useState('home',['name','age','sex'])const storeActions=useActions('home',['setName'])constchangeName=()=>{             storeAction.setName('李四')}return{             changeName,...storeState,...storeActions};},};</script>