Vue Composition API function - window size

useWindowSize.ts

import { Ref, onMounted, onUnmounted, reactive, toRefs } from '@vue/composition-api'

interface WindowSize {
  x: Ref<number>
  y: Ref<number>
}

export function useWindowSize(): WindowSize {
  const windowSize = reactive({ x: 0, y: 0 })
  const resizeListener = () => {
    ({ innerWidth: windowSize.x, innerHeight: windowSize.y } = window)
  }
  onMounted(() => window.addEventListener('resize', resizeListener))
  onUnmounted(() => window.removeEventListener('resize', resizeListener))
  resizeListener()
  return toRefs(windowSize)
}

export default useWindowSize