v-model 其实是一个语法糖 通过 props 和 emit 组合而成的

默认值的改变

• prop：value -> modelValue；
• 事件：input -> update:modelValue；
• v-bind 的 .sync 修饰符和组件的 model 选项已移除
• 新增 支持多个 v-model
• 新增 支持自定义 修饰符 Modifiers

案例

单个 v-model 绑定

子组件

<template>
     <div v-if='propData.modelValue' class="dialog">
         <div class="dialog-header">
             <div>标题</div><div @click="close">x</div>
         </div>
         <div class="dialog-content">
            内容
         </div>
         
     </div>
</template>
 
<script setup lang='ts'>
 
type Props = {
   modelValue: boolean
}
 
const propData = defineProps<Props>()
 
const emit = defineEmits(['update:modelValue'])
 
const close = () => {
     emit('update:modelValue', false)
}
 
</script>
 
<style lang='less'>
.dialog{
    width: 300px;
    height: 300px;
    border: 1px solid #ccc;
    position: fixed;
    left:50%;
    top:50%;
    transform: translate(-50%,-50%);
    &-header{
        border-bottom: 1px solid #ccc;
        display: flex;
        justify-content: space-between;
        padding: 10px;
    }
    &-content{
        padding: 10px;
    }
}
</style>

父组件

<template>
  <button @click="show = !show">开关{{show}}</button>
  <Dialog v-model="show"></Dialog>
</template>
 
<script setup lang='ts'>
import Dialog from "./components/Dialog/index.vue";
import {ref} from 'vue'
const show = ref(false)
</script>
 
<style>
</style>

多个 v-model 绑定

子组件

<template>
     <div v-if='modelValue' class="dialog">
         <div class="dialog-header">
             <div>标题---{{title}}</div><div @click="close">x</div>
         </div>
         <div class="dialog-content">
            内容
         </div>
         
     </div>
</template>
 
<script setup lang='ts'>
 
type Props = {
   modelValue: boolean,
   title: string
}
 
const propData = defineProps<Props>()
 
const emit = defineEmits(['update:modelValue','update:title'])
 
const close = () => {
     emit('update:modelValue',false)
     emit('update:title','我要改变')
}
 
</script>
 
<style lang='less'>
.dialog{
    width: 300px;
    height: 300px;
    border: 1px solid #ccc;
    position: fixed;
    left:50%;
    top:50%;
    transform: translate(-50%,-50%);
    &-header{
        border-bottom: 1px solid #ccc;
        display: flex;
        justify-content: space-between;
        padding: 10px;
    }
    &-content{
        padding: 10px;
    }
}
</style>

父组件

<template>
  <button @click="show = !show">开关{{show}} ----- {{title}}</button>
  <Dialog v-model:title='title' v-model="show"></Dialog>
</template>
 
<script setup lang='ts'>
import Dialog from "./components/Dialog/index.vue";
import {ref} from 'vue'
const show = ref(false)
const title = ref('我是标题')
</script>
 
<style>
</style>

自定义修饰符