React hook to track window resize events.

useWindowSize.js

import { useEffect, useState } from 'react';

/**
 * @return {{width: Number, height: Number}}
 */
function getWindowSize() {
  return {
    width: window.innerWidth,
    height: window.innerHeight,
  };
}

/**
 * @return {{width: Number, height: Number}}
 */
function useWindowSize() {
  const [size, setSize] = useState(getWindowSize());
  useEffect(() => {
    const listener = () => setSize(getWindowSize());
    window.addEventListener('resize', listener);
    return () => window.removeEventListener('resize', listener);
  }, []);
  return size;
}

export default useWindowSize;