運(yùn)行 時(shí)報(bào)如圖錯(cuò)誤,是什么原因？ eslint是什么？

app.vue：

<template>
  <div id="app">
    <img src="./assets/logo.png">
    <!--<router-view/>-->
    <hello></hello>
    <base></base>
  </div>
</template>

<script>
import Hello from './components/HelloWorld'
import Base from './components/base'
export default {
  name: 'app',
  components:{
      Hello,
      Base
  }
}
</script>

base.vue:

<template>
    <div id="base1">
        <h1>site:{{site}}</h1>
        <h1>url:{{url}}</h1>
        <h1>{{detail()}}</h1>
    </div>
</template>

<script>
    var vm = new Vue({
        el:'#base1',
        data(){
            return {
                site:"baidu",
                url:"http://baidu.com"
            }
            
        }
        
    })
</script>