[Vuejs]-How to get _value properties in Vue 3 ref

This is how you can get it

<script setup>
import { ref, onMounted } from 'vue'

const cube = ref(null)

onMounted(() => {
  console.log(cube.value.clientWidth)
})
</script>

<template>
  <div ref="cube">nice</div>
</template>

<style scoped>
  div {
    width: 200px;
    height: 300px;
    background-color: orange;
  }
</style>

Here is an example.

Regarding Vue’s lifecycle hooks, setup() doesn’t have the element attached to the DOM yet, hence why you may not have anything regarding window-related properties of your object.