text: import { ref, onMounted, onUnmounted } from 'vue'
  export default function useScroll() {
    const top = ref(0)
  
    function update() {
      top.value = window.scrollY
    }
  
    onMounted(() => {
      window.addEventListener('scroll', update)
    })
  
    onUnmounted(() => {
      window.removeEventListener('scroll', update)
    })
  
    return { top }
  }
  