a easy drop down components
main.js
import Vue from 'vue'
import App from './App.vue'
import DropDown from "../drop-down";
Vue.use(DropDown);
new Vue({
render: h => h(App),
}).$mount('#app')<DropDown>
<h1>你好</h1>
<div slot="overlay" class="menu"></div>
</DropDown>