vue28：组件化开发和根组件

简单写个点击事件 

<template>  
  <div class="app">
    <div class="box" @click="fn"></div>
  </div>
</template>

<script>
export default {
  //导出当前组件的配置项
  //里面可以提供 data methods computed watch 生命周期 等
  methods: {
    fn () {
      alert('click')
    }
  },
  name: 'app'
}
</script>

<style>
.app {
  width: 400px;
  height: 400px;
  background-color: antiquewhite;
}
.app .box{
  width: 100px;
  height: 100px;
  background-color: aquamarine;
}
</style>