1 什么是状态管理

其实是数据管理但是为了更好的指出是由于状态的变化导致数据的变化(响应式数据),我们称之为状态管理.

2 Vuex的状态管理

组件只能直接读取state,而不能直接修改state,必须通过mutation才能修改.(pinia可以直接读取和修改state)

3 Vuex的安装

npm install vuex

4 创建Store

文件结构

1 创建store,使用state(核心一)

import { createStore } from 'vuex'const store = createStore({state: () => ({// 模拟数据// counter: 100,rootCounter: 100,}),//用于修改state的mutationsmutations: {increment(state) {state.counter++}}})export default store

2 使用和修改state,解构state获取数据

<template><div class="app">//模板中使用<h2>Home当前计数: {{ $store.state.counter }}</h2>//options API 使用<h2>Computed当前计数: {{ storeCounter }}</h2>//setUP API 使用<h2>Setup当前计数: {{ counter }}</h2>// 修改state<button @click="increment">+1</button></div>
</template><script>export default {computed: {storeCounter() {return this.$store.state.counter}}}
</script><script setup>import { toRefs } from 'vue'import { useStore } from 'vuex'const store = useStore()//解构state获取数据,counter,可以是多个数据,起别名等(推荐)const { counter } = toRefs(store.state)function increment() {// store.state.counter++store.commit("increment")}
</script><style scoped>
</style>

5 getters的基本使用 对state数据进行加工(核心二)

inde.js代码

const store = createStore({state: () => ({// 模拟数据// counter: 100,rootCounter: 100,name: "coderwhy",level: 100,avatarURL: "http://xxxxxx",friends: [{ id: 111, name: "why", age: 20 },{ id: 112, name: "kobe", age: 30 },{ id: 113, name: "james", age: 25 }],}),getters: {// 1.基本使用doubleCounter(state) {return state.counter * 2},totalAge(state) {return state.friends.reduce((preValue, item) => {return preValue + item.age}, 0)},// 2.在该getters属性中, 获取其他的gettersmessage(state, getters) {return `name:${state.name} level:${state.level} friendTotalAge:${getters.totalAge}`},// 3.getters是可以返回一个函数的, 调用这个函数可以传入参数(了解)getFriendById(state) {return function(id) {const friend = state.friends.find(item => item.id === id)return friend}}},

vue代码

 <template><div class="app"><!-- <button @click="incrementLevel">修改level</button> --><h2>doubleCounter: {{ $store.getters.doubleCounter }}</h2><h2>friendsTotalAge: {{ $store.getters.totalAge }}</h2><h2>message: {{ $store.getters.message }}</h2><!-- 根据id获取某一个朋友的信息 --><h2>id-111的朋友信息: {{ $store.getters.getFriendById(111) }}</h2><h2>id-112的朋友信息: {{ $store.getters.getFriendById(112) }}</h2></div>
</template>

6 Mutation基本使用,state的修改(核心三)

重要的原则: 不要在mutation方法中执行异步操作

mutations: {increment(state) {state.counter++},changeName(state, payload) {state.name = payload},incrementLevel(state) {state.level++},changeInfo(state, newInfo) {state.level = newInfo.levelstate.name = newInfo.name// 重要的原则: 不要在mutation方法中执行异步操作},

methods: {changeName() {// this.$store.state.name = "李银河"//带外部参数的修改this.$store.commit("changeName", "王小波")},incrementLevel() {this.$store.commit("incrementLevel")},changeInfo() {//外部参数是一个对象this.$store.commit("changeInfo", {name: "王二",level: 200})}}}
</script>

7 actions的基本使用 ,异步派发(核心四)

使用dispatch函数进行分发

actions: {incrementAction(context) {// console.log(context.commit) // 用于提交mutation// console.log(context.getters) // getters// console.log(context.state) // statecontext.commit("increment")},changeNameAction(context, payload) {context.commit("changeName", payload)},},

<template>
<div class="home"><h2>当前计数: {{ $store.state.counter }}</h2><button @click="counterBtnClick">发起action修改counter</button><h2>name: {{ $store.state.name }}</h2><button @click="nameBtnClick">发起action修改name</button>
</div>
</template><script>export default {methods: {counterBtnClick() {this.$store.dispatch("incrementAction")},nameBtnClick() {this.$store.dispatch("changeNameAction", "aaa")}}
}
</script><script setup></script><style scoped>
</style>

actions的异步操作

8 module的基本使用,抽出模块(核心五)

定义一个单独的home.js文件

export default {state: () => ({// 服务器数据banners: [],recommends: []}),mutations: {changeBanners(state, banners) {state.banners = banners},changeRecommends(state, recommends) {state.recommends = recommends}},actions: {fetchHomeMultidataAction(context) {return new Promise(async (resolve, reject) => {// 3.await/asyncconst res = await fetch("http://123.207.32.32:8000/home/multidata")const data = await res.json()// 修改state数据context.commit("changeBanners", data.data.banner.list)context.commit("changeRecommends", data.data.recommend.list)resolve("aaaaa")})}}
}

导入index.js

//导入模块对象
import homeModule from './modules/home'
//导入模块
modules: {home: homeModule,}

使用xxx.vue文件

<template><div class="home"><h2>Home Page</h2><ul><!-- 使用数据时需要模块名 state.modulename.xxx --><template v-for="item in $store.state.home.banners" :key="item.acm"><li>{{ item.title }}</li></template></ul></div>
</template><script>
</script><script setup>import { useStore } from 'vuex'// 调用方法时,不需要模块名const store = useStore()store.dispatch("fetchHomeMultidataAction").then(res => {console.log("home中的then被回调:", res)})</script><style scoped>
</style>