4.toRefs 把props变成响应式数据

<template>
  <div style="margin: 30px">
    {{ count }}
  </div>
</template>
<script>
import { toRefs } from "vue";
export default {
  props: {
    count: {
      type: Number,
      default: 10,
    }
  },
  setup(props) {
    const { count } = toRefs(props);
    return {
      count,
    };
  },
};
</script>