provide 与 inject

• 作用：实现祖与后代组件间通信

• 套路：父组件有一个 provide 选项来提供数据，后代组件有一个 inject 选项来开始使用这些数据

• 具体写法：

1. 祖组件中：

• setup(){
  	......
      let car = reactive({name:'奔驰',price:'40万'})
      provide('car',car)
      ......
  }
  

  　　2.后代组件中：

• setup(props,context){
  	......
      const car = inject('car')
      return {car}
  	......
  }
  

  　　

例子：

App.vue

<template>
  <div class="container">
    <h2>我是App(祖)组件</h2>
    <Child></Child>
  </div>
</template>

<script>
import {reactive,provide} from 'vue'
import Child from './components/Child';

export default {
  name: 'App',
  components:{
    Child
  },
  setup() {
    let car = reactive({name:'奔驰',price:'40w'})
   
    provide('car',car) //给自己的后代组件传递数据
    //return {car}
  }
 
}
</script>
 
<style>
  .container{
    background-color: grey;
    padding: 10px;
  }
</style>

<template>
    <div class="child">
        <h2>我是child子组件</h2>
        汽车：{{car.name}}，价格：{{car.price}}
        <Sun></Sun>
    </div>
</template>

<script>
import {inject} from 'vue'
import Sun from './Sun'

export default {
  name: 'Child',
  components:{
    Sun
  },
  setup() {
    
    let car = inject('car')

    return{car}
  }
 
}
</script>

<style>
    .child{
        background-color: skyblue;
        padding: 10px;
    }
</style>
  

Sun.vue

<template>
  <div class="sun">
    <h2>我是孙子组件</h2>
    汽车：{{name}}，价格：{{price}}
  </div>
</template>

<script>
import {inject,toRefs} from 'vue'

export default {
  name: 'Child',
  setup() {
    let car = inject('car')

    return{...toRefs(car)}

  }
 
}
</script>

<style>
  .sun{
    background-color: orange;
    padding: 10px;
  }
</style>