tutorbookapp/tutorbook

import { useEffect, useState } from 'react';

export interface WindowSize {
  width?: number;
  height?: number;
}

// React hook that returns an object containing the window's width and height.
// If executed server-side (no window object) the value of width and height will
// be undefined. See: https://usehooks.com/useWindowSize/
export default function useWindowSize(): WindowSize {
  // Initialize state with undefined width/height so server and client renders match
  // Learn more here: https://joshwcomeau.com/react/the-perils-of-rehydration/
  const [windowSize, setWindowSize] = useState<WindowSize>({
    width: undefined,
    height: undefined,
  });

  useEffect(() => {
    // Handler to call on window resize
    function handleResize(): void {
      // Set window width/height to state
      setWindowSize({
        width: window.innerWidth,
        height: window.innerHeight,
      });
    }

    // Add event listener
    window.addEventListener('resize', handleResize);

    // Call handler right away so state gets updated with initial window size
    handleResize();

    // Remove event listener on cleanup
    return () => window.removeEventListener('resize', handleResize);
  }, []); // Empty array ensures that effect is only run on mount

  return windowSize;
}