const app = Vue.createApp({
    data() {
      return {
        num: 0,
        text: ''
      };
    },
    methods: {
      addNum() {
        console.log('addNum');
        this.num++
      },
    }
  });

  app.component('button-counter', {
    methods: {
      childEmitName(){
        this.$emit('parentEmitName')
      }
    },
    template: `<button type="button" @click="childEmitName">內層button-counter按鈕</button>`
  });
  app.mount('#app');