vuejs单文件组件测试报错

childComponent组件child-component.vue:

<template>
    <div id="child-template">
        <input type="text" v-model="msg">
        <button @click="notify">Dispatch Event</button>
        <slot>回退</slot>
    </div>
</template>

<script>
    export default {
        data(){
            return {msg:'hello'};
        },
        methods:{
            notify(){
                if(this.msg.trim()){
                    console.log(this.msg);
                    this.msg = '';
                }
            }
        }
    }
</script>

入口js文件:

import Vue from 'vue';
import childComponent from './child-component.vue';
var vm = new Vue({
  el: '#app',
  data:{
    name:'laoqiren'
  },
  components:{
    childComponent
  }
});

index.html:

<div id="app">
      <child-component></child-component>
</div>

浏览器报错：

Uncaught TypeError: Cannot read property 'indexOf' of undefined

请问这是怎么回事呢？谢谢

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demo 不谢 https://github.com/TIGERB/eas...