console 命令行工具 X clear

console

new Vue({
  el: '#app',
  data: {
    map: {
      a: "1"
    }
  },
  methods: {
    remveFromMap() {
      this.a = null;
    }
  }
});

<div id='app'>
  <p v-if="null == map.a">
    {{map.a}}
  </p>
  <button @click="removeFromMap">
    删除
  </button>
</div>