vue获取元素属性

<template>
      <van-sticky id="stickyID" ref="stickyRef" :offset-top="stickyOffsetTop"/>
</template>

<script setup lang="ts">
  const stickyOffsetTop = ref();
  
  const stickyRef = ref();
  const stickyID = ref();
  
  onMounted(() => {
    const navBarHeight = parseInt(
      getComputedStyle(document.documentElement).getPropertyValue(
        "--van-nav-bar-height"
      ),
      10
    );
    const searchPadding = parseInt(
      getComputedStyle(document.documentElement).getPropertyValue(
        "--van-search-padding"
      ),
      10
    );
    const searchInputHeight = parseInt(
      getComputedStyle(document.documentElement).getPropertyValue(
        "--van-search-input-height"
      ),
      10
    );
    const elementID = document.getElementById("stickyID");
    const elementRef = stickyRef.value.$el.offsetHeight;
    stickyOffsetTop.value = navBarHeight + elementID.offsetHeight;
    console.log(elementID.offsetHeight);
    console.log(elementRef);
  });
<script>