JAVASCRIPT

Tracking Window Dimensions with `useWindowSize`

Build a custom React `useWindowSize` hook to efficiently track and react to changes in the browser window's dimensions for responsive UIs.

import { useState, useEffect } => 'react';

function useWindowSize() {
  const [windowSize, setWindowSize] = useState({
    width: undefined,
    height: undefined,
  });

  useEffect(() => {
    function handleResize() {
      setWindowSize({
        width: window.innerWidth,
        height: window.innerHeight,
      });
    }

    window.addEventListener('resize', handleResize);

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

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

  return windowSize;
}

// Example Usage:
// function MyComponent() {
//   const { width, height } = useWindowSize();
//   return (
//     <div>
//       <p>Window Width: {width}</p>
//       <p>Window Height: {height}</p>
//     </div>
//   );
// }

How it works: The `useWindowSize` hook provides the current `width` and `height` of the browser window. It attaches a `resize` event listener when the component mounts and cleans it up when the component unmounts, ensuring efficient updates and preventing memory leaks.

Tracking Window Dimensions with `useWindowSize`

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