vue 非父子通信-event bus 事件总线

1.作用

非父子组件之间，进行简易消息传递。(复杂场景→ Vuex)

2.步骤

创建一个都能访问的事件总线（空Vue实例）

import Vue from 'vue'
const Bus = new Vue()
export default Bus

A组件（接受方），监听Bus的 $on事件

created () {Bus.$on('sendMsg', (msg) => {this.msg = msg})
}

B组件（发送方），触发Bus的$emit事件
```
Bus.$emit('sendMsg', '这是一个消息')
```

3.代码示例

EventBus.js

import Vue from 'vue'
const Bus  =  new Vue()
export default Bus

BaseA.vue(接受方)

<template><div class="base-a">我是A组件（接收方）<p>{{msg}}</p>  </div>
</template>

<script>
import Bus from '../utils/EventBus'
export default {data() {return {msg: '',}},
}
</script>

<style scoped>
.base-a {width: 200px;height: 200px;border: 3px solid #000;border-radius: 3px;margin: 10px;
}
</style>

BaseB.vue(发送方)

<template><div class="base-b"><div>我是B组件（发布方）</div><button>发送消息</button></div>
</template>

<script>
import Bus from '../utils/EventBus'
export default {
}
</script>

<style scoped>
.base-b {width: 200px;height: 200px;border: 3px solid #000;border-radius: 3px;margin: 10px;
}
</style>

App.vue

<template><div class="app"><BaseA></BaseA><BaseB></BaseB> </div>
</template>

<script>
import BaseA from './components/BaseA.vue'
import BaseB from './components/BaseB.vue' 
export default {components:{BaseA,BaseB}
}
</script>

<style>

</style>