手写 v-on （运用 directive， 简化版的 v-on）

import Vue from "vue";
// import App from "./App.vue";

Vue.config.productionTip = false;

Vue.directive('y', {
  inserted: function(el) {
    el.addEventListener('click', ()=>{console.log('y')})
  }
})

new Vue({
  directives: {
    on2: {
      inserted(el, info) {
        el.addEventListener(info.arg, info.value)
      },
      unbind(el, info) {        //  调用结束后，解除监听
        el.removeEventListener(info.arg, info.value)
      }
    }
  },
  methods: {
    hi() {
      console.log('hi')
    }
  },
  template: `
    <button v-on2:click='hi'>点我</button>
  `,
  // render: h => h(App)
}).$mount("#app");