import Vue from 'vue'

const bus = new Vue()
export default bus

<!--html结构-->
<template>
 <div>
  <p>我是add组件的num:{{num}} </p>
  <button @click='add'>增加</button>
 </div>
</template>

// js
<script>
import bus from '../bus.js'
export default {
 data() {
  return {
   num: ''
  }
 },
 methods: {
  add() {
   if (this.num) {
    this.num++
    bus.$emit('num-change', this.num)
   } else {
    this.num = 1
    bus.$emit('num-change', this.num)
   }
  }
 }
}
</script>

<!--html结构-->
<template>
 <div>
  <p>我是sub组件的num:{{num}}</p>
 </div>
</template>

// js
<script>
import bus from '../bus.js'
export default {
 data() {
  return {
   num: ''
  }
 },
 created() {
  bus.$on('num-change', num => {
   this.num = num
  })
 }
}
</script>

<!--html结构-->
<template>
 <div id="app">
  <h1>我是app父组件的newNum:{{share.newNum}}</h1>
  <hr>
  <!--将同一个对象同时传给两个子组件-->
  <addnum :share1='share'></addnum>
  <hr>
  <subnum :share2='share'></subnum>
 </div>
</template>

// js
import addnum from './components/add'
import subnum from './components/sub'

export default {
 data() {
  return {
   share: {
    newNum: 1
   }
  }
 },
 components: {
  addnum, subnum
 }
}

<!--html结构-->
<template>
 <div>
  <p>我是add组件的newNum:{{share1.newNum}} </p>
  <button @click='add'>增加</button>
 </div>
</template>

//js
<script>
export default {
 methods: {
  add() {
   this.share1.newNum++
  }
 },
 props: {
  share1: {
   type: Object,
  }
 }
}
</script>

<!--html结构-->
<template>
 <div>
  <p>我是sub组件的newNum:{{share2.newNum}}</p>  
  <button @click='numSub'>减少</button>
 </div>
</template>

// js
<script>
export default {
 methods: {
  numSub() {
   this.share2.newNum--
  }
 },
 props: {
  share2: {
   type: Object,
  }
 }
}
</script>