vue3兄弟组件传值app.config.globalProperties.$bus = new mitt() //在组

$ npm install --save mitt

main.js中

   import { createApp } from 'vue'
    import mitt from "mitt"
    import App from './App.vue'
    import router from './router/index'
    import ElementPlus from 'element-plus'
    import 'element-plus/theme-chalk/index.css'
    const app=createApp(App)
    app.use(router).use(ElementPlus).mount('#app')//正常配置
    
    //挂载事务总线
    app.config.globalProperties.$bus = new mitt()

//在组件A中使用事务总线触发某个动作

  this.$bus.emit('add',this.age)

//在组件B中监听动作的发生

   this.$bus.on('add',(res)=>{
    console.log(res)
    })