引入第三方库pubsub.js:

npm i pubsub-js

Student.vue

import pubsub from 'pubsub-js'

 methods:{
    sendStudentName(){
      // this.$bus.$emit('hello',this.name)
      pubsub.publish('hello',666)
    }
  },

School.vue

import pubsub from 'pubsub-js'

 mounted() {
    // console.log("school",this.x)
/*    this.$bus.$on('hello',(data)=>{
      console.log('我是school组件，收到了数据',data)
    })*/
    this.pubId = pubsub.subscribe('hello',function (msgName,data){
      console.log('有人发布了hello消息，hello消息的回调执行了',msgName,data)
    })
  },
  beforeDestroy() {
    // this.$off('hello')
    pubsub.unsubscribe(this.pubId)
  },
}

TodoList案例使用消息订阅实现删除功能：

App.vue:

import pubsub from 'pubsub-js'

 mounted() {
    this.$bus.$on('checkTodo',this.checkTodo)
    this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)
  },
  beforeDestroy() {
    this.$bus.$off('checkTodo')
    pubsub.unsubscribe(this.pubId)
  }
}

MyItem.vue:

import pubsub from 'pubsub-js'

  methods:{
    //勾选or取消勾选
    handleCheck(id){
      //通知App组件将对应的todo对象的done值取反
      // this.checkTodo(id)
      this.$bus.$emit('checkTodo',id)
    },
    //删除
    handleDelete(id){
        if (confirm('确定删除吗')){  //confirm根据用户的交互来决定到底是布尔值为真还是为假，点击确定为真，点击取消为假
          // this.deleteTodo(id)
            pubsub.publish('deleteTodo',id)
        }
    }