昨天在做项目时遇到了一个问题 在Vue中监听obj.name时新增了一个属性 但是发现属性并没有变化 后来查询了官方文档发现Vue不允许动态添加prototype来执行深度监听

对象

如下：

<template>
  <div class="about">
    <h1>{{dataList.name}}</h1>
    <h1>{{dataList.id}}</h1>
    <h1>{{dataList.type}}</h1>
  </div>
</template>
<script>
export default {
  data(){
    return {
      dataList:{name:123,id:456},
    }
  },
  mounted(){
    setTimeout(() => {
      // this.$set(this.dataList,'type','student');
      this.dataList.type='student'
    }, 2000);
  }
}
</script>

两秒后页面不会发生任何变化 改动后：

<template>
  <div class="about">
    <h1>{{dataList.name}}</h1>
    <h1>{{dataList.id}}</h1>
    <h1>{{dataList.type}}</h1>
  </div>
</template>
<script>
export default {
  data(){
    return {
      dataList:{name:123,id:456},
    }
  },
  mounted(){
    setTimeout(() => {
      this.$set(this.dataList,'type','student');
      // this.dataList.type='student'
    }, 2000);
  }
}
</script>

出现student

数组

<template>
  <div class="about">
    <h1>{{ dataList.name }}</h1>
    <h1>{{ dataList.id }}</h1>
    <h1>{{ dataList.type }}</h1>
    <div v-for="(item,idex) in dataArr" :key="idex">{{item}}</div>
  </div>
</template>
<script>
export default {
  data() {
    return {
      dataList: { name: 123, id: 456 },
      dataArr: ["1", "2", "3"],
    };
  },
  mounted() {
    setTimeout(() => {
      // this.$set(this.dataList,'type','student');
      // this.dataList.type='student'
      this.dataArr[0] = "4";
    }, 2000);
  },
};
</script>

两秒后。。。什么都没有发生

<template>
  <div class="about">
    <h1>{{ dataList.name }}</h1>
    <h1>{{ dataList.id }}</h1>
    <h1>{{ dataList.type }}</h1>
    <div v-for="(item,idex) in dataArr" :key="idex">{{item}}</div>
  </div>
</template>
<script>
export default {
  data() {
    return {
      dataList: { name: 123, id: 456 },
      dataArr: ["1", "2", "3"],
    };
  },
  mounted() {
    setTimeout(() => {
      // this.$set(this.dataList,'type','student');
      // this.dataList.type='student'
      // this.dataArr[0] = "4";
      this.dataArr.splice(0, 1, '4')
    }, 2000);
  },
};
</script>

成功刷新