@revoloo/cypress6/packages/runner-ct/src/lib/useWindowSize.ts

Cypress.io end to end testing tool

import * as React from 'react'

export function useWindowSize () {
  // 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] = React.useState({
    width: window.innerWidth,
    height: window.innerHeight,
  })

  React.useEffect(() => {
    // Handler to call on window resize
    function handleResize () {
      // 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
}