vue3中获取dom元素和操作实现方法

<div class="icon-box" ref="menu_item">
 <div
    class="menu-box"
    v-for="(item, index) in iconMenus"
    :key="index"
    @click="clickItem(item)"
  >
    <span :class="[item.imageRef, 'item-image']"></span>
    <div class="item-content">
      {{ item.menuName }}
    </div>
  </div>
 </div>

.menu-box {
    width: 144px;
    height: 144px;
    margin-top: 5px;
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
    .item-image {
      display: block;
      font-size: 60px;
      padding: 15px;
      &::before {
        color: v-bind(zeroTheme);
      }
    }
    .item-content {
      font-size: 26px;
      display: inline-block;
      white-space: nowrap;
    }
    .item-content-flag {
      font-size: 26px;
      position: absolute;
      display: inline-block;
      white-space: nowrap;
      left: 0;
      bottom: 22px;
      white-space: nowrap;
      -webkit-animation: todayScroll 4s linear infinite;
      animation: todayScroll 5s linear infinite;
    }
  }

const menu_item = ref(null);

menu_item.value.children.forEach(element => {
      let parentWith = element.offsetWidth;
      let childrenWith = element.children[1].offsetWidth;
      if (childrenWith >= parentWith - 10) {
        element.children[1].classList.add('item-content-flag');
      }
    });

<div class="icon-box" ref="menu_item"></div>
const menu_item = ref(null);

const menu_item = ref(null);
menu_item.value.children

vNode.offsetWidth

vNode.classList.add('newClass')

headerOrangeMask: require('@/assets/img/header-blue-mask.png'), //首页顶部的我的图标

const myMask = ref(null);
nextTick(() => {
  myMask.value.style.backgroundImage = `url(${headerOrangeMask})`; //设置背景图片
});

// 主动暴露childMethod方法
defineExpose({ noticeSwiper });
//公告轮播-父组件请求完成后调用
function noticeSwiper() {
  console.log("子组件中的方法执行了")
}

<Notice ref="noticeNode"></Notice>
const noticeNode = ref(null); //公告组件的node
//获取公告信息
function getNotice() {
  store.dispatch('notice/getNoticeList').then(() => {
    noticeNode.value.noticeSwiper(); //调用子组件方法轮播公告
  });
}