Vuex
Vuex是什么
概念:专门在Vue中实现集中式状态(数据)管理的一个Vue插件,对Vue应用中多个组件的共享状态进行集中式的管理(读/写),也是一种组件间通信的方式,且适用于任意组件间通信
什么时候使用
- 多组件依赖于同一状态
- 来自不同组件的行为需要变更同一状态
工作原理
求和案例
src/store/index.js该文件用于创建Vuex中最为核心的store
import Vue from 'vue'
import Vuex from 'vuex' // 引入Vuex
Vue.use(Vuex) // 应用Vuex插件
// 准备actions——用于响应组件中的动作
const actions = {
/* jia(context,value){
console.log('actions中的jia被调用了')
context.commit('JIA',value)
},
jian(context,value){
console.log('actions中的jian被调用了')
context.commit('JIAN',value)
}, */
jiaOdd(context,value){ // context 相当于精简版的 $store
console.log('actions中的jiaOdd被调用了')
if(context.state.sum % 2){
context.commit('JIA',value)
}
},
jiaWait(context,value){
console.log('actions中的jiaWait被调用了')
setTimeout(()=>{
context.commit('JIA',value)
},500)
}
}
// 准备mutations——用于操作数据(state)
const mutations = {
JIA(state,value){
console.log('mutations中的JIA被调用了')
state.sum += value
},
JIAN(state,value){
console.log('mutations中的JIAN被调用了')
state.sum -= value
}
}
// 准备state——用于存储数据
const state = {
sum:0 //当前的和
}
// 创建并暴露store
export default new Vuex.Store({
actions,
mutations,
state,
})
src/components/Count.vue
<template>
<div>
<h1>当前求和为:{{ $store.state.sum }}</h1>
<select v-model.number="n">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button @click="increment">+</button>
<button @click="decrement">-</button>
<button @click="incrementOdd">当前求和为奇数再加</button>
<button @click="incrementWait">等一等再加</button>
</div>
</template>
<script>
export default {
name:'Count',
data() {
return {
n:1, //用户选择的数字
}
},
methods: {
increment(){
this.$store.commit('JIA',this.n)
},
decrement(){
this.$store.commit('JIAN',this.n)
},
incrementOdd(){
this.$store.dispatch('jiaOdd',this.n)
},
incrementWait(){
this.$store.dispatch('jiaWait',this.n)
},
}
}
</script>
<style lang="css">button{margin-left: 5px;}</style>
getters
- 概念:当state中的数据需要经过加工后再使用时,可以使用getters加工,相当于全局计算属性
- 在store.js中追加getters配置
......
const getters = {
bigSum(state){
return state.sum * 10
}
}
// 创建并暴露store
export default new Vuex.Store({
......
getters
})
- 组件中读取数据$store.getters.bigSum
src/store/index.js
import Vue from 'vue' // 引入Vue核心库
import Vuex from 'vuex' // 引入Vuex
Vue.use(Vuex) // 应用Vuex插件
// 准备actions对象——响应组件中用户的动作
const actions = {
addOdd(context,value){
console.log("actions中的addOdd被调用了")
if(context.state.sum % 2){context.commit('ADD',value)}
},
addWait(context,value){
console.log("actions中的addWait被调用了")
setTimeout(()=>{context.commit('ADD',value)},500)
},
}
// 准备mutations对象——修改state中的数据
const mutations = {
ADD(state,value){state.sum += value},
SUB(state,value){state.sum -= value}
}
// 准备state对象——保存具体的数据
const state = {
sum:0 // 当前的和
}
// 准备getters对象——用于将state中的数据进行加工
const getters = {
bigSum(){
return state.sum * 10
}
}
//创建并暴露store
export default new Vuex.Store({
actions,
mutations,
state,
getters
})
src/Count.vue
<template>
<div>
<h1>当前求和为:{{ $store.state.sum }}</h1>
<h3>当前求和的10倍为:{{ $store.getters.bigSum }}</h3>
<select v-model.number="n">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button @click="increment">+</button>
<button @click="decrement">-</button>
<button @click="incrementOdd">当前求和为奇数再加</button>
<button @click="incrementWait">等一等再加</button>
</div>
</template>
<script>
export default {
name:'Count',
data() {
return {
n:1,
}
},
methods: {
increment(){this.$store.commit('ADD',this.n)},
decrement(){this.$store.commit('SUBTRACT',this.n)},
incrementOdd(){this.$store.dispatch('addOdd',this.n)},
incrementWait(){this.$store.dispatch('addWait',this.n)},
},
}
</script>
<style>button{margin-left: 5px;}</style>
四个map方法
-
mapState方法:用于帮助映射state中的数据为计算属性、
computed: { // 借助mapState生成计算属性:sum、school、subject(对象写法一) ...mapState({sum:'sum',school:'school',subject:'subject'}), // 借助mapState生成计算属性:sum、school、subject(数组写法二) ...mapState(['sum','school','subject']), },
-
mapGetters方法:用于帮助映射getters中的数据为计算属性
computed: { //借助mapGetters生成计算属性:bigSum(对象写法一) ...mapGetters({bigSum:'bigSum'}), //借助mapGetters生成计算属性:bigSum(数组写法二) ...mapGetters(['bigSum']) },
-
mapActions方法:用于帮助生成与actions对话的方法,即包含$store.dispatch(xxx)的函数
methods:{ //靠mapActions生成:incrementOdd、incrementWait(对象形式) ...mapActions({incrementOdd:'jiaOdd',incrementWait:'jiaWait'}) //靠mapActions生成:incrementOdd、incrementWait(数组形式) ...mapActions(['jiaOdd','jiaWait']) }
-
mapMutations方法:用于帮助生成与mutations对话的方法,即包含$store.commit(xxx)的函数
methods:{ //靠mapActions生成:increment、decrement(对象形式) ...mapMutations({increment:'JIA',decrement:'JIAN'}), //靠mapMutations生成:JIA、JIAN(对象形式) ...mapMutations(['JIA','JIAN']), }
src/components/Count.vue
<template>
<div>
<h1>当前求和为:{{ sum }}</h1>
<h3>当前求和的10倍为:{{ bigSum }}</h3>
<h3>我是{{ name }},我在{{ school }}学习</h3>
<select v-model.number="n">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button @click="increment(n)">+</button>
<button @click="decrement(n)">-</button>
<button @click="addOdd(n)">当前求和为奇数再加</button>
<button @click="addWait(n)">等一等再加</button>
</div>
</template>
<script>
import {mapState, mapGetters, mapMutations, mapActions} from 'vuex' //🔴
export default {
name: 'Count',
data() {
return {
n:1, //用户选择的数字
}
},
computed: {
...mapState(['sum','school','name']),
...mapGetters(['bigSum'])
},
methods: {
...mapMutations({increment:'ADD', decrement:'SUBTRACT'}),
...mapActions(['addOdd', 'addWait'])
},
}
</script>
<style>
button{
margin-left: 5px;
}
</style>
多组件共享数据案例
App.vue
<template>
<div>
<Count/><hr/>
<Person/>
</div>
</template>
<script>
import Count from "./components/Count.vue";
import Person from "./components/Person.vue";
export default {
name: "App",
components: { Count, Person },
};
</script>
src/store/index.js
import Vue from 'vue'
import Vuex from 'vuex'
Vue.use(Vuex)
const actions = {
jiaOdd(context,value){
console.log('actions中的jiaOdd被调用了')
if(context.state.sum % 2){
context.commit('JIA',value)
}
},
jiaWait(context,value){
console.log('actions中的jiaWait被调用了')
setTimeout(()=>{
context.commit('JIA',value)
},500)
}
}
//准备mutations——用于操作数据(state)
const mutations = {
JIA(state,value){
console.log('mutations中的JIA被调用了')
state.sum += value
},
JIAN(state,value){
console.log('mutations中的JIAN被调用了')
state.sum -= value
},
ADD_PERSON(state,value){
console.log('mutations中的ADD_PERSON被调用了')
state.personList.unshift(value)
}
}
//准备state——用于存储数据
const state = {
sum: 0,
school: '尚硅谷',
subject: '前端',
personList: []
}
//准备getters——用于将state中的数据进行加工
const getters = {
bigSum(state){
return state.sum*10
}
}
//创建并暴露store
export default new Vuex.Store({
actions,
mutations,
state,
getters
})
Count.vue
<template>
<div>
<h1>当前求和为:{{ sum }}</h1>
<h3>当前求和放大10倍为:{{ bigSum }}</h3>
<h3>我在{{ school }},学习{{ subject }}</h3>
<h3 style="color:red">Person组件的总人数是:{{ personList.length }}</h3>
<select v-model.number="n">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button @click="increment(n)">+</button>
<button @click="decrement(n)">-</button>
<button @click="incrementOdd(n)">当前求和为奇数再加</button>
<button @click="incrementWait(n)">等一等再加</button>
</div>
</template>
<script>
import {mapState,mapGetters,mapMutations,mapActions} from 'vuex'
export default {
name:'Count',
data() {
return {
n:1, //用户选择的数字
}
},
computed:{
...mapState(['sum','school','subject','personList']),
...mapGetters(['bigSum'])
},
methods: {
...mapMutations({increment:'JIA',decrement:'JIAN'}),
...mapActions({incrementOdd:'jiaOdd',incrementWait:'jiaWait'})
}
}
</script>
<style lang="css">button{margin-left: 5px;}</style>
Person.vue
<template>
<div>
<h1>人员列表</h1>
<h3 style="color:red">Count组件求和为:{{ sum }}</h3>
<input type="text" placeholder="请输入名字" v-model="name">
<button @click="add">添加</button>
<ul>
<li v-for="p in personList" :key="p.id">{{ p.name }}</li>
</ul>
</div>
</template>
<script>
import {nanoid} from 'nanoid'
import { mapState } from "vuex"
export default {
name:'Person',
data() {
return {
name:''
}
},
computed:{
personList(){return this.$store.state.personList},
sum(){return this.$store.state.sum}
},
methods: {
add(){
if (this.name === "") return
const personObj = {id:nanoid(),name:this.name}
this.$store.commit('ADD_PERSON',personObj)
this.name = ''
}
},
}
</script>
模块化+命名空间
-
目的:让代码更好维护,让多种数据分类更加明确
-
修改store.js 为了解决不同模块命名冲突的问题,将不同模块的namespaced: true,之后在不同页面中引入getteractionsmutations时,需要加上所属的模块名
store.js
const countAbout = { namespaced: true, // 开启命名空间 state: {x:1}, mutations: { ... }, actions: { ... }, getters: { bigSum(state){ return state.sum * 10 } } } const personAbout = { namespaced: true, // 开启命名空间 state: { ... }, mutations: { ... }, actions: { ... } } const store = new Vuex.Store({ modules: { countAbout, personAbout } })
-
开启命名空间后,组件中读取state数据
// 方式一:自己直接读取 this.$store.state.personAbout.list // 方式二:借助mapState读取: ...mapState('countAbout',['sum','school','subject']),
-
开启命名空间后,组件中读取getters数据
//方式一:自己直接读取 this.$store.getters['personAbout/firstPersonName'] //方式二:借助mapGetters读取: ...mapGetters('countAbout',['bigSum'])
-
开启命名空间后,组件中调用dispatch
//方式一:自己直接dispatch this.$store.dispatch('personAbout/addPersonWang',person) //方式二:借助mapActions: ...mapActions('countAbout',{incrementOdd:'jiaOdd',incrementWait:'jiaWait'})
-
开启命名空间后,组件中调用commit
//方式一:自己直接commit this.$store.commit('personAbout/ADD_PERSON',person) //方式二:借助mapMutations: ...mapMutations('countAbout',{increment:'JIA',decrement:'JIAN'}),
src/store/index.js
import Vue from 'vue'
import Vuex from 'vuex'
import countOptions from './count' // 引入count
import personOptions from './person' // 引入person
Vue.use(Vuex)
//创建并暴露store
export default new Vuex.Store({
modules:{
countAbout:countOptions,
personAbout:personOptions,
}
})
src/store/count.js
export default {
namespaced:true,
actions: {
addOdd(context,value){
console.log("actions中的addOdd被调用了")
if(context.state.sum % 2){
context.commit('ADD',value)
}
},
addWait(context,value){
console.log("actions中的addWait被调用了")
setTimeout(()=>{
context.commit('ADD',value)
},500)
}
},
mutations: {
ADD(state,value){ state.sum += value },
SUBTRACT(state,value){ state.sum -= value }
},
state: {
sum:0,
school:'尚硅谷',
subject: '前端'
},
getters: {
bigSum(state){ return state.sum * 10 }
}
}
src/store/person.js
import axios from "axios"
import { nanoid } from "nanoid"
export default{
namespaced:true,
actions:{
addPersonWang(context,value){
if(value.name.indexOf('王') === 0){
context.commit('ADD_PERSON',value)
}else{
alert('添加的人必须姓王!')
}
},
addPersonServer(context){
axios.get('http://api.uixsj.cn/hitokoto/get?type=social').then(
response => {
context.commit('ADD_PERSON',{id:nanoid(),name:response.data})
},
error => { alert(error.message) }
)
}
},
mutations:{
ADD_PERSON(state,value){
console.log('mutations中的ADD_PERSON被调用了')
state.personList.unshift(value)
}
},
state:{
personList:[]
},
getters:{
firstPersonName(state){ return state.personList[0].name }
}
}
src/components/Count.vue
<template>
<div>
<h1>当前求和为:{{ sum }}</h1>
<h3>当前求和的10倍为:{{ bigSum }}</h3>
<h3>我是{{ name }},我在{{ school }}学习</h3>
<h3 style="color:red">Person组件的总人数是:{{ personList.length }}</h3>
<select v-model.number="n">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<button @click="increment(n)">+</button>
<button @click="decrement(n)">-</button>
<button @click="incrementOdd(n)">当前求和为奇数再加</button>
<button @click="incrementWait(n)">等一等再加</button>
</div>
</template>
<script>
import {mapState,mapGetters,mapMutations,mapActions} from 'vuex'
export default {
name:'Count',
data() {
return {
n:1, // 用户选择的数字
}
},
computed:{
...mapState('countAbout',['sum','school','name']),
...mapState('personAbout',['personList']),
...mapGetters('countAbout',['bigSum']),
}
methods: {
...mapMutations('countAbout',{increment:'ADD',decrement:'SUBTRACT'}),
...mapActions('countAbout',{incrementOdd:'addOdd',incrementWait:'addWait'})
},
}
</script>
<style>button{margin-left: 5px;}</style>
src/components/Person.vue
<template>
<div>
<h1>人员列表</h1>
<h3 style="color:red">Count组件求和为:{{ sum }}</h3>
<h3>列表中第一个人的名字是:{{ firstPersonName }}</h3>
<input type="text" placeholder="请输入名字" v-model="name">
<button @click="add">添加</button>
<button @click="addWang">添加一个姓王的人</button>
<button @click="addPerson">随机添加一个人</button>
<ul>
<li v-for="p in personList" :key="p.id">{{ p.name }}</li>
</ul>
</div>
</template>
<script>
import {nanoid} from 'nanoid'
export default {
name: 'Person',
data() {
return {
name:''
}
},
computed: {
personList(){
return this.$store.state.personAbout.personList
},
sum(){
return this.$store.state.countAbout.sum
},
firstPersonName(){
return this.$store.getters['personAbout/firstPersonName']
}
},
methods: {
add(){
const personObj = {id:nanoid(),name:this.name}
this.$store.commit('personAbout/ADD_PERSON',personObj)
this.name = ''
},
addWang(){
const personObj = {id:nanoid(),name:this.name}
this.$store.dispatch('personAbout/addPersonWang',personObj)
this.name = ''
},
addPerson(){
this.$store.dispatch('personAbout/addPersonServer')
}
},
}
</script>
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