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Vue2进阶之Vue3高级用法

news 2025/11/5 3:15:32

Vue3高级用法

响应式
- Vue2：Object.defineProperty
- - Object.defineProperty
  - this.$set设置响应式
- Vue3：Proxy
composition API
- Vue2 option API和Vue3 compositionAPI
- reactive和shallowReactive
- readonly效果
- toRefs效果
生命周期
- main.js
- index.html
- LifeCycle.vue
异步组件元素节点
- 正常写
- index.html
- main.js
- Async.vue
- AsyncComp.vue
- 使用异步
- - main.js
teleport 传送门—createPortal React
- index.html
- main.js
- Dialog.vue
自定义hooks
- index.html
- main.js
- useMousePosition.js
- MouseMove.vue

作业：Vue3官网所有内容过一遍 Vue3

响应式

Vue2：Object.defineProperty
Vue3：Proxy

Vue2：Object.defineProperty

Object.defineProperty

//Vue2：Object.definePropertyconst initData={value:1
}const data={}Object.keys(initData).forEach(key=>{Object.defineProperty(data,key,{// getter setterget(){console.log("访问",key)return initData[key]},set(val){console.log("设置值",key)initData[key]=val}})
})

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this.$set设置响应式

set给目的对象添加响应式属性后，并触发事件更新

this.$set(data,a,1)

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Vue3：Proxy

// Vue3：Proxy
const person={name:"张三"
}let proxy=new Proxy(person,{get:function(target,key){if(key in target){return target[key]}throw new Error(`${key} is not defined`)},set(target,key,val){console.log("设置值",key)target[key]=val}}
)
let obj=Object.create(proxy)

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proxy的正规写法：

// Proxy正规写法
const initData={value:1
}
let proxy=new Proxy(initData,{get:function(target,key,receiver){console.log("访问",key)return Reflect.get(target,key,receiver)},set:function(target,key,val,receiver){console.log("修改",key)return Reflect.set(target,key,val,receiver)}}
)

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拓展
怎么将esNext转换为es5写法？
通过babel，国外主流的swc转换

composition API

Vue2 option API和Vue3 compositionAPI

Vue3的compositionAPI和Vue2的optionsAPI的最大的区别是：更加倾向于函数式编程以及Vue3支持多个根节点
Vue2:

<template><!--XXXX-->
</template>
<script>export default {data(){return{ XXXX }},methods:{},computed:{}}
</script>
<style></style>

Vue2最容易产生的问题是：写一个文件一开始还好，写着写着就发现这个文件内容非常非常多，非常非常繁琐。
OptionAPI非常非常容易导致一个文件内容非常非常多，越往后越难改，非常非常容易出bug
Rect相对于Vue不容易写出那么夸张的效果
Vue2的mixin将组件单一内容拆解到一个文件，太灵活了，对多人协作不友好

=>Vue3主要解决的就是这个问题，将明确的逻辑抽象到一起

React=>自定义hook，将一部分的逻辑功能放到单一组件里去维护

App.vue

<template><div class="mine"></div>
</template><script>
import {defineComponent,ref,isRef} from 'vue'
export default defineComponent({// 相当于Vue2生命周期中的beforeCreate,createdsetup(){const count=ref(10)const user="张三"console.log("count,user",count,count.value,user)console.log("count is ref?",isRef(count))console.log("user is ref?",isRef(user))}
})
</script>

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reactive和shallowReactive

<template><div class="mine"></div>
</template><script>
import {defineComponent,reactive,shallowReactive} from 'vue'
export default defineComponent({// 相当于Vue2生命周期中的beforeCreate,createdsetup(){const person={name:"张三",age:18,contacts:{phone:12345}}const personReactive=reactive(person)console.log("person reactive",personReactive)console.log("person reactive name",personReactive.name)console.log("person reactive contacts",personReactive.contacts)console.log("--------------分割线------------------------")const shallowPersonReactive=shallowReactive(person)console.log("shallow person reactive",shallowPersonReactive)console.log("shallow person reactive name",shallowPersonReactive.name)console.log("shallow person reactive contacts",shallowPersonReactive.contacts)}
})
</script>

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readonly效果

<template><div class="mine"></div>
</template><script>
import {defineComponent,ref,reactive,readonly} from 'vue'
export default defineComponent({// 相当于Vue2生命周期中的beforeCreate,createdsetup(){const count=ref(10)const obj=reactive({abc:18,count,userInfo:{age:66}})console.log("reactive obj:",obj)// 在Proxy的set中，是不允许做修改的const objOnly=readonly(obj)  console.log("readonly obj:",objOnly)objOnly.abc=100console.log("readonly obj:",objOnly)}
})
</script>

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toRefs效果

<template><div class="mine"></div>
</template><script>
import {defineComponent,ref,isRef,reactive,shallowReactive,readonly, toRefs} from 'vue'
export default defineComponent({// 相当于Vue2生命周期中的beforeCreate,createdsetup(){const count=ref(10)const obj=reactive({abc:18,count,userInfo:{age:66}})console.log("reactive obj:",obj)console.log("toRefs obj",toRefs(obj))}
})
</script>

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如果是通过ref创建出来的，一般是RefImpl，如果是通过toRefs创建出来的，一般把toRefs视为一个对象，针对对象里的所有属性，全部转换为toRefs的效果

生命周期

经常应用的场景：
1.初始化 mount
2.数据变化 update
3.卸载 unmount

加入LiftCycle组件

main.js

import { createApp } from 'vue'
import App from './App.vue'import LifeCycle from './LifeCycle.vue'createApp(App).mount('#app')createApp(LifeCycle).mount('#lifeCycle')

index.html

<div id="lifeCycle"></div>

全部：

<!DOCTYPE html>
<html lang=""><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1.0"><link rel="icon" href="<%= BASE_URL %>favicon.ico"><title><%= htmlWebpackPlugin.options.title %></title></head><body><noscript><strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong></noscript><div id="app"></div><!-- built files will be auto injected --><div id="lifeCycle"></div></body>
</html>

LifeCycle.vue

<template><div>{{ count }}{{ name }}</div><button @click="addNumber">+1</button><button @click="updateName">update name</button>
</template>
<script>
export default {data() {return {count:0,name:"张三"}},methods:{addNumber(){this.count++},updateName(){this.name = "李四"}},//  1.初始化，data还不能用beforeCreate(){console.log("beforeCreate")},//   data可以用,dom不可用created(){console.log("created")},//   挂载之前，DOM还没有生成beforeMount(){console.log("beforeMount")},//   在VNode(初次渲染/更新)渲染时调用renderTracked({key,target,type}){console.log("renderTracked",key,target,type)},//  挂载之后，DOM已经生成mounted(){console.log("mounted")console.log("-------------------------------------------------------------")},//  2.updaterenderTriggered({key,target,type}){console.log("renderTriggered",key,target,type)},beforeUpdate(){console.log("beforeUpdate")},renderTracked({key,target,type}){console.log("renderTriggered",key,target,type)},updated(){console.log("updated")},// 3.卸载beforeUnmount(){console.log("beforeUnmount")},unmounted(){console.log("unmounted")}
}
</script>
<style scoped></style>

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异步组件元素节点

正常写

src
- Async.vue
- components
  - AsyncComp.vue

index.html

<!-- 3.异步组件元素节点 -->
<div id="async"></div>

<!DOCTYPE html>
<html lang=""><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1.0"><link rel="icon" href="<%= BASE_URL %>favicon.ico"><title><%= htmlWebpackPlugin.options.title %></title></head><body><noscript><strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong></noscript><!-- 1.composition 元素节点 --><div id="app"></div><!-- built files will be auto injected --><!-- 2.生命周期元素节点 --><div id="lifeCycle"></div><!-- 3.异步组件元素节点 --><div id="async"></div></body>
</html>

main.js

import { createApp } from 'vue'
import App from './App.vue'import LifeCycle from './LifeCycle.vue'import Async from './Async.vue'
import AsyncComp from './components/AsyncComp.vue'createApp(App).mount('#app')createApp(LifeCycle).mount('#lifeCycle')const async=createApp(Async)
async.component("async-comp",AsyncComp)
async.mount('#async')

Async.vue

<template>ASYNC<async-comp></async-comp>
</template><script setup lang="ts"></script><style scoped></style>

AsyncComp.vue

<template><div>async defineComponent</div>
</template><script setup lang="ts"></script><style scoped></style>

在这里插入图片描述
但是这样执行

pnpm run build

打包后，只会生成一个js文件
在这里插入图片描述

使用异步

main.js

const AsyncComp=defineAsyncComponent(()=>import('./components/AsyncComp.vue'))async.component("async-comp",AsyncComp)

全部代码：

import { createApp,defineAsyncComponent } from 'vue'
import App from './App.vue'import LifeCycle from './LifeCycle.vue'import Async from './Async.vue'
// import AsyncComp from './components/AsyncComp.vue'createApp(App).mount('#app')createApp(LifeCycle).mount('#lifeCycle')const async=createApp(Async)const AsyncComp=defineAsyncComponent(()=>import('./components/AsyncComp.vue'))async.component("async-comp",AsyncComp)
async.mount('#async')

再执行

pnpm run build

会生成两个js文件

在这里插入图片描述
这两个文件是将我们异步的组件给单独拿出来，将异步组件单独拿出来的效果是，因为要做的是异步组件的动态引入，一般是额外使用或之后去用，就没有必要跟原先代码单独一起打包。

对应的是React.lazy和React中的suspense

const myComponent=React.lazy(()=>import('./Component'))function MyComponent(){return (<div><Suspense fallback={<Loading />}><Component /></Suspense></div>)
}

teleport 传送门—createPortal React

将子节点渲染到父节点以外的DOM的方式

src
Dialog.vue

index.html

<!-- 4.teleport 元素节点 -->
<div id="dialog"></div>

全部代码：

<!DOCTYPE html>
<html lang=""><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1.0"><link rel="icon" href="<%= BASE_URL %>favicon.ico"><title><%= htmlWebpackPlugin.options.title %></title></head><body><noscript><strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong></noscript><!-- 1.composition 元素节点 --><div id="app"></div><!-- built files will be auto injected --><!-- 2.生命周期元素节点 --><div id="lifeCycle"></div><!-- 3.异步组件元素节点 --><div id="async"></div><!-- 4.teleport 元素节点 --><div id="dialog"></div></body>
</html>

main.js

const dialog=createApp(Dialog)
dialog.mount('#dialog')

全部代码：

import { createApp,defineAsyncComponent } from 'vue'
import App from './App.vue'import LifeCycle from './LifeCycle.vue'import Async from './Async.vue'
import Dialog from './Dialog.vue'
// import AsyncComp from './components/AsyncComp.vue'createApp(App).mount('#app')createApp(LifeCycle).mount('#lifeCycle')const async=createApp(Async)const AsyncComp=defineAsyncComponent(()=>import('./components/AsyncComp.vue'))async.component("async-comp",AsyncComp)
async.mount('#async')const dialog=createApp(Dialog)
dialog.mount('#dialog')

Dialog.vue

<template><div class="portals"><button @click="showNotification">切换弹窗</button><teleport to="#dialog"><div v-if="isOpen" class="notification">这是一个弹窗</div></teleport></div>
</template>
<script>
import { ref } from 'vue';export default {setup(){const isOpen=ref(false)let closePopupconst showNotification=()=>{isOpen.value=trueclearTimeout(closePopup)closePopup=setTimeout(()=>{isOpen.value=false},20000)}return {isOpen,showNotification}}
}
</script>
<style scoped>
.notification{position: fixed;bottom: 20px;background-color: #fff;border: 1px solid #ccc;width: 300px;padding:30px;
}
</style>

弹窗是挂载在dialog下的，而不是protals下
在这里插入图片描述

自定义hooks

hooks最重要的特点：对于我们来说，不需要关心内部的逻辑，而且与Vue2相比，提供了一个非常合理的方式，使用Vue2的option API很容易写出三五千行的代码，但是对于函数式编程来说，按照逻辑功能拆分下来，一个文件至少包含一个功能，其他功能引用即可。

public
- index.html
src
- hooks
  - useMousePosition.js
- MouseMove.vue
- main.js

index.html

<!-- 5.自定义hook -->
<div id="mousemove"></div>

全部代码：

<!DOCTYPE html>
<html lang=""><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1.0"><link rel="icon" href="<%= BASE_URL %>favicon.ico"><title><%= htmlWebpackPlugin.options.title %></title></head><body><noscript><strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong></noscript><!-- 1.composition 元素节点 --><div id="app"></div><!-- built files will be auto injected --><!-- 2.生命周期元素节点 --><div id="lifeCycle"></div><!-- 3.异步组件元素节点 --><div id="async"></div><!-- 4.teleport 元素节点 --><div id="dialog"></div><!-- 5.自定义hook --><div id="mousemove"></div></body>
</html>

main.js

import MouseMove from './MouseMove.vue'const mousemove=createApp(MouseMove)
mousemove.mount('#mousemove')

全部代码：

import { createApp,defineAsyncComponent } from 'vue'
import App from './App.vue'import LifeCycle from './LifeCycle.vue'import Async from './Async.vue'
import Dialog from './Dialog.vue'
// import AsyncComp from './components/AsyncComp.vue'
import MouseMove from './MouseMove.vue'// createApp(App).mount('#app')// createApp(LifeCycle).mount('#lifeCycle')// const async=createApp(Async)// const AsyncComp=defineAsyncComponent(()=>import('./components/AsyncComp.vue'))// async.component("async-comp",AsyncComp)
// async.mount('#async')// const dialog=createApp(Dialog)
// dialog.mount('#dialog')const mousemove=createApp(MouseMove)
mousemove.mount('#mousemove')

useMousePosition.js

import { onMounted, onUnmounted, ref } from "vue";function useMousePosition() {const x=ref(0)const y=ref(0)const updateMouse=e=>{x.value=e.pageXy.value=e.pageY}onMounted(()=>{document.addEventListener('click',updateMouse)}) onUnmounted(()=>{document.removeEventListener('click',updateMouse)})return{x,y}
}export default useMousePosition

MouseMove.vue

<!-- 提供鼠标位置自定义hooks -->
<template><div><p>X：{{x}}</p><p>Y：{{y}}</p></div>
</template><script>
import { defineComponent } from 'vue';
import useMousePosition from './hooks/useMousePosition';export default defineComponent({setup(){const {x,y}=useMousePosition()return {x,y}}
})
</script><style scoped></style>

请添加图片描述

Vue3高级用法

响应式

Vue2：Object.defineProperty

Object.defineProperty

this.$set设置响应式

Vue3：Proxy

composition API

Vue2 option API和Vue3 compositionAPI

reactive和shallowReactive

readonly效果

toRefs效果

生命周期

main.js

index.html

LifeCycle.vue

异步组件元素节点

正常写

index.html

main.js

Async.vue

AsyncComp.vue

使用异步

main.js

teleport 传送门—createPortal React

index.html

main.js

Dialog.vue

自定义hooks

index.html

main.js

useMousePosition.js

MouseMove.vue

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