windowResize.js

import React, { useState, useEffect } from "react";
export default function App() {

  const [windowWidth, setWindowWidth] = useState(window.innerWidth);
  const resizeHandler = () => {
    setWindowWidth(window.innerWidth);
  };

  useEffect(() => {
    window.addEventListener("resize", resizeHandler);
  }, []);

  return (
    <div>
      {windowWidth}
    </div>
  );
}