VUE之组件通信（一）

1、props

概述：props是使用频率最高的一种通信方式，常用与：父<——>子。

• 若 父传子：属性值是非函数。
• 若 子传父：属性值是函数。

父组件：

<template>
  <div class="father">
    <h3>父组件</h3>
    <h4>汽车：{
  
  {car}}</h4>
    <h4 v-show="toy">子给的玩具：{
  
  {toy}} </h4>
    <Child :car="car" :sendToy="getToy" />
  <div>
</template>

<script setup lang="ts" name="Father">
  import Child from './Child.vue'
  import {ref} from 'vue'

  //数据
  let car = ref('奔驰')
  let toy = ref('')
  // 方法
  function getToy(value:string){
    toy.value = value
  }
</script>

<template>
  <div class="child">
    <h3>子组件</h3>
    <h4>玩具：{
  
  {toy}}</h4>
    <h4>父给的车：{
  
  {car}} </h4>
    <button @click="sendToy(toy)">把玩具给父亲</button>
  <div>
</template>

<script setup lang="ts" name="Child">
  import {ref} from 'vue'

  //数据
  let toy = ref('奥特曼')
  // 声明接收props
  defineProps(['car','sendToy'])
</script>

2、自定义事件

<template>
  <div class="child">
    <h3>子组件</h3>
    <h4>玩具：{
  
  {toy}}</h4>
    <button @click="emit('send-toy',toy)">测试</button>
  <div>
</template>

<script setup lang="ts" name="Child">
  import {ref} from 'vue'
  let toy = ref('奥特曼')

  //声明事件
  const emit = defineEmits(['send-toy'])
</script>

<template>
  <div class="father">
    <h3>父组件</h3>
    <h4 v-show="toy">子给的玩具：{
  
  {toy}}</h4>
    <Child @send-toy='saveToy'/>
  <div>
</template>

<script setup lang="ts" name="Father">
  import Child from './Child.vue'
  import {ref} from 'vue';
  let toy = ref('')

  function saveToy(value:string){
    console.log('xyz',value)
    toy.value = value
  }
</script>

3、mitt

安装mitt 

npm i mitt

>> utils/emitter.ts
// 引入mitt
import mitt from 'mitt'
// 调用mitt得到emitter.能绑定事件，触发事件
const emitter = mitt()
// 绑定时间
emitter.on('test1',()=>{
  console.log('test1被调用了')
})
emitter.on('test2',()=>{
  console.log('test2被调用了')
})


// 触发事件
setImterval(() => {
   emitter.emit('test1')
   emitter.emit('test2')
},2000);


setTimeout(()=>{
   //emitter.off('test1')
   //emitter.off('test2')
   emitter.all.clear()
},3000);

//暴露
export fefault emitter 

>> main.ts

import emitter from '@/utils/emitter'

>> Child1.vue
<template>
   <div class="child1">
     <h3>子组件1</h3>
     <h4>玩具：{
  
  {toy}}</h4>
     <button @click="emitter.emit('send-toy',toy)">玩具给弟弟</button>
   </div>
</template>

<script setup lang="ts" name="Child1">
   import {ref} from 'vue'
   let toy = ref('奥特曼')

</script>

>> Child2.vue

<template>
   <div class="child2">
     <h3>子组件2</h3>
     <h4>电脑：{
  
  {computer}}</h4>
     <h4>哥哥给的玩具：{
  
  {toy}}</h4>
   </div>
</template>

<script setup lang="ts" name="Child2">
   import {ref,onUnmounted} from 'vue'
   import emitter from '@/utils/emitter';
   let computer= ref('联想')
   let toy = ref('')
   // 给emitter绑定send-toy事件
   emitter.on('send-toy',(value:string)=>{
      toy.value = value
   })
//在组件卸载时解绑send-toy事件
onUnmounted(()=>{
   emitter.off('send-toy')
})

</script>