fec/lib/hooks/useWindowSize.js

import { useEffect, useState } from 'react'

export default function useWindowSize() {
  const isClient = typeof window === 'object',
    [windowSize, setWindowSize] = useState(getSize)

  function getSize() {
    return {
      width: isClient ? window.innerWidth : undefined,
      height: isClient ? window.innerHeight : undefined,
    }
  }

  useEffect(() => {
    if (!isClient) {
      return false
    }

    function handleResize() {
      setWindowSize(getSize())
    }

    window.addEventListener('resize', handleResize)
    return () => window.removeEventListener('resize', handleResize)
  }, []) // Empty array ensures that effect is only run on mount and unmount

  return windowSize
}