强烈推荐!Vue3.2中的setup语法糖

<template>
  <my-component :num="num" @click="addNum" />
</template>

<script setup>
  import { ref } from 'vue';
  import MyComponent from './MyComponent .vue';

  // 像在平常的setup中一样的写,但是不需要返回任何变量
  const num= ref(0)       //在此处定义的 num 可以直接使用
  const addNum= () => {   //函数也可以直接引用,不用在return中返回
    num.value++
  }
</script>

//必须使用驼峰命名

<template>
    <zi-hello></zi-hello>
</template>

<script setup>
  import ziHello from './ziHello'
</script>

<template>
  <div class="die">
    <h3>我是父组件</h3>
    <zi-hello :name="name"></zi-hello>
  </div>
</template>

<script setup>
  import ziHello from './ziHello'
  
  import {ref} from 'vue'
  let name = ref('赵小磊========')
</script>

<template>
  <div>
    我是子组件{{name}} // 赵小磊========
  </div>
</template>

<script setup>
  import {defineProps} from 'vue'

  defineProps({
   name:{
     type:String,
     default:'我是默认值'
   }
 })
</script>

<template>
  <div>
    我是子组件{{name}}
    <button @click="ziupdata">按钮</button>
  </div>
</template>

<script setup>
  import {defineEmits} from 'vue'

  //自定义函数，父组件可以触发
  const em=defineEmits(['updata'])
  const ziupdata=()=>{
    em("updata",'我是子组件的值')
  }

</script>

<template>
  <div class="die">
    <h3>我是父组件</h3>
    <zi-hello @updata="updata"></zi-hello>
  </div>
</template>

<script setup>
  import ziHello from './ziHello'
  
  const updata = (data) => {
    console.log(data); //我是子组件的值
  }
</script>

<template>
  <div>
    我是子组件
  </div>
</template>

<script setup>
  import {defineExpose,reactive,ref} from 'vue'
  let ziage=ref(18)
  let ziname=reactive({
    name:'赵小磊'
  })
  //暴露出去的变量
  defineExpose({
    ziage,
    ziname
  })
</script>

<template>
  <div class="die">
    <h3 @click="isclick">我是父组件</h3>
    <zi-hello ref="zihello"></zi-hello>
  </div>
</template>

<script setup>
  import ziHello from './ziHello'
  import {ref} from 'vue'
  const zihello = ref()

  const isclick = () => {
    console.log('接收ref暴漏出来的值',zihello.value.ziage)
    console.log('接收reactive暴漏出来的值',zihello.value.ziname.name)
  }
</script>