老生常谈vue3组件通信方式

<!-- list是我们要传递的数据 -->
<child-components :list="list"></child-components>

<template>
  <ul>
    <li v-for="i in props.list" :key="i">{{ i }}</li>
  </ul>
</template>
<script setup>
import { defineProps } from 'vue'
const props = defineProps({
  list: {
    type: Array,
    default: () => [],
  },
})
</script>

<!-- add是子组件要传递的动作,handleAdd是监听到之后执行的事件 -->
<child-components @add="handleAdd"></child-components>
<script>
 const list = ref([1,2,3])
 const handleAdd = value => {
  list.value.push(value)
}
</script>

const emits = defineEmits(['add'])
emits('add', 1)

<ChildComponent v-model:list="list" />
// 等价于
<ChildComponent :list="pageTitle" @update:list="list = $event" />

const emits = defineEmits(['update:list'])
emits('update:list', arr)

<template>
    <div>
        <Child ref="child"></Child>
        <button @click="show">Show Child Message</button>
    </div>
</template>
<script setup>
import { getCurrentInstance } from '@vue/runtime-core';
import Child from './Child.vue';
const currentInstance = getCurrentInstance()
function show() {
    currentInstance.$refs.child.alertMessage()
}
</script>

<template>
    <div>
        <h1>{{ message }}</h1>
    </div>
</template>
<script setup>
import { ref } from '@vue/reactivity';
let message = ref('我是子元素').value
const alertMessage = function () {
    alert(message)
}
defineExpose({
    message,
    alertMessage
})
</script>

// 父组件中
provide('list', list.value)

// 子组件中
const list = inject('list')