SOURCE

let i = 0
const state = Vue.observable({ i: 0 })
var Main = {
  render(h) {
    return h('div', {
      on: {
        click() {
          state.i += 1
          console.log('current i is', state.i)
        }
      }
    }, '点我啊！'+state.i) 
  }
}
var Ctor = Vue.extend(Main)
new Ctor().$mount('#app')

<script src="//unpkg.com/vue/dist/vue.js"></script>
<script src="//unpkg.com/element-ui@1.4.5/lib/index.js"></script>
<div id="app">

</div>

@import url("//unpkg.com/element-ui@1.4.5/lib/theme-default/index.css");