Vue3.2 (setup syntactic sugar) passing values between parent and child components

1. Father sends message to son

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The parent component sends information to the child component
index.vue

import Back from '@/components/common/back.vue'
const title = ref('你好呀')

// template部分
<Back :title="title" />

Child components receive parent component information
/components/common/back.vue

<script setup>
import {
    
     toRefs } from 'vue'
const props = defineProps({
    
    
	title: {
    
    
		type: String,
		default: '标题',
		required: true,
	},
})
const {
    
     title } = toRefs(props)
</script>
<template>
	<span>{
    
    {
    
     title }}</span>
</template>

2. The son sends a message to the father

The child component sends information to the parent component
/components/relax/relax-index.vue

const emit = defineEmits(['goTreeHode'])
const goHold = () => {
    
    
  emit('goTreeHode', true)
}

//template
<button  @click="goHold">传值</button>

The parent component receives the child component information
relax.vue

import RelaxIndex from '@/components/relax/relax-index.vue'

//template
 <RelaxIndex @goTreeHode="goTreeHode" />