Vue.js 3事件总线 [英] Vue.js 3 Event Bus

问题描述

如何在Vue 3中创建事件总线?

How to create Event Bus in Vue 3?

在Vue 2中，它是:

In Vue 2, it was:

export const bus = new Vue();

bus.$on(...)
bus.$emit(...)

---

在Vue 3中，Vue不再是构造函数，并且Vue.createApp({});返回的对象没有$on和$emit方法.

---

In Vue 3, Vue is not a constructor anymore, and Vue.createApp({}); returns an object that has no $on and $emit methods.

推荐答案

如官方文档，您可以使用 mitt 库在组件之间调度事件，假设我们有一个侧边栏和header，其中包含一个用于关闭/打开侧边栏的按钮，我们需要该按钮来切换侧边栏组件内的某些属性:

As suggested in official docs you could use mitt library to dispatch events between components, let suppose that we a sidebar and header which contains a button that close/open the sidebar and we need that button to toggle some property inside the sidebar component :

导入该库并创建该发射器的实例，并将其定义为

in main.js import that library and create an instance of that emitter and define as a global property:

安装:

 npm install --save mitt

用法:

import { createApp } from 'vue'
import App from './App.vue'
import mitt from 'mitt';
const emitter = mitt();
let app=createApp(App)
app.config.globalProperties.emitter = emitter
app.mount('#app')

标头中的

发出带有某些有效负载的toggle-sidebar事件:

<template>
  <header>
    <button  @click="toggleSidebar"/>toggle</button>
  </header>
</template>
<script >
export default { 
  data() {
    return {
      sidebarOpen: true
    };
  },
  methods: {
    toggleSidebar() {
      this.sidebarOpen = !this.sidebarOpen;
      this.emitter.emit("toggle-sidebar", this.sidebarOpen);
    }
  }
};
</script>

在边栏中接收带有有效负载的事件:

In sidebar receive the event with the payload:

<template>
  <aside class="sidebar" :class="{'sidebar--toggled':!isOpen}">
  ....
  </aside>
</template>
<script>
export default {
  name: "sidebar",
  data() {
    return {
      isOpen: true
    };
  },
  mounted() { 
    this.emitter.on("toggle-sidebar", isOpen => {
      this.isOpen = isOpen;
    });
  }
};
</script>

对于使用composition api的用户，可以按以下方式使用emitter:

For those using composition api they could use emitter as follows :

import { getCurrentInstance } from 'vue'
export default{

   setup(){
      const internalInstance = getCurrentInstance(); 
      const emitter = internalInstance.appContext.config.globalProperties.emitter;

       ...
     },
  ...

}

这篇关于Vue.js 3事件总线的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！