刚好H5项目有用到这个需求，页面加载完成后获取当前页面高度，记录一下。^_^

<template>
<div class="wrap" :style="{height:hHeight+'px'}">
</div>
</template>
<script lang='ts'>
import { defineComponent, reactive, nextTick, onMounted, toRefs } from "vue";
export default defineComponent({
  name: "Aboutus",
  setup() {
    let state = reactive({
      hHeight: 0,//页面高度
    });
  onMounted(() => {
    nextTick(()=>{
        state.hHeight = document.documentElement.clientHeight;
        console.log(document.documentElement.clientHeight)
    })
  })
  return {
      ...toRefs(state)
  }
  },
});
</script>

用vue3.2版本的也可以用语法糖来处理，直接上代码：

<template>
  <div class="wrap" :style="{height:state.hHeight+'px'}">
   </div>
</template>
<script setup>
import { reactive, nextTick } from "vue"
const state = reactive({
    hHeight: 0
})
nextTick(()=>{
     state.hHeight = document.documentElement.clientHeight;
     console.log(document.documentElement.clientHeight)
 })
</script>

亲测可用，大家可以试试！