Vue3中的toRef和toRefs

基础实例

先看例子吧。

• main.js

import { createApp } from 'vue'
import App from './App.vue'

createApp(App).mount('#app')

• App.vue

<template>
  <Demo/>
template>

<script>
import Demo from './components/Demo.vue'
export default {
  name: 'App',
  components: {
    Demo
  }
}
script>

• Demo.vue

<template>
  <h2>姓名：{{person.name}}h2>
  <h2>年龄：{{person.age}}h2>
  <h2>薪酬：{{person.job.salary}}Kh2>
  <button @click="person.name+='~'">修改姓名button> 
  <button @click="person.age++">增长年龄button> 
  <button @click="person.job.salary++">涨薪button>
template>

<script>
import {reactive} from "vue";
export default {
  name:"Demo",
  setup(){
    let person = reactive({
      name:"张三",
      age:18,
      job:{
        salary:30
      }
    })

    return {
      person
    }
  }
}
script>

• 启动应用，测试效果
  

错误修改

好，现在我们来仔细看下Demo.vue，template标签里{{person.name}}、{{person.age}}、{{person.job.salary}}、person.name+='~'、person.age++、person.job.salary++，person person的，哪儿哪儿都是person。能不能不重复写person，就像下图右侧那样。

先尝试下吧，比如这样修改Demo.vue，如下。

<template>
  <h2>姓名：{{name}}h2>
  <h2>年龄：{{age}}h2>
  <h2>薪酬：{{salary}}Kh2>
  <button @click="name+='~'">修改姓名button> 
  <button @click="age++">增长年龄button> 
  <button @click="salary++">涨薪button>
template>

<script>
import {reactive} from "vue";
export default {
  name:"Demo",
  setup(){
    let person = reactive({
      name:"张三",
      age:18,
      job:{
        salary:30
      }
    })

    return {
      name:person.name,
      age:person.age,
      salary:person.job.salary
    }
  }
}
script>

来测试下效果：name、age和salary失去了响应式。

正确修改：使用toRef

这时，toRef的给力就凸显出来了。瞧哈！

<template>
  <h2>姓名：{{name}}h2>
  <h2>年龄：{{age}}h2>
  <h2>薪酬：{{salary}}Kh2>
  <button @click="name+='~'">修改姓名button> 
  <button @click="age++">增长年龄button> 
  <button @click="salary++">涨薪button>
template>

<script>
import {reactive, toRef} from "vue";
export default {
  name:"Demo",
  setup(){
    let person = reactive({
      name:"张三",
      age:18,
      job:{
        salary:30
      }
    })

    return {
      name:toRef(person,"name"),
      age:toRef(person,"age"),
      salary:toRef(person.job,"salary")
    }
  }
}
script>

toRef的功能类似ref，让数据保持响应式。

正确修改：使用toRefs

toRef，将一个数据变成响应式数据。
toRefs，将多个数据变成响应式数据。

<template>
  <h2>姓名：{{name}}h2>
  <h2>年龄：{{age}}h2>
  <h2>薪酬：{{job.salary}}Kh2>
  <button @click="name+='~'">修改姓名button> 
  <button @click="age++">增长年龄button> 
  <button @click="job.salary++">涨薪button>
template>

<script>
import {reactive,toRefs} from "vue";
export default {
  name:"Demo",
  setup(){
    let person = reactive({
      name:"张三",
      age:18,
      job:{
        salary:30
      }
    })
    console.log("toRef(person)=",toRefs(person));
    return {
      ...toRefs(person)
    }
  }
}
script>

小结