Overleaf/services/web/frontend/js/shared/hooks/use-resize-observer.js

import { useLayoutEffect, useRef } from 'react'

function useResizeObserver(observedElement, observedData, callback) {
  const resizeObserver = useRef()

  function observe() {
    resizeObserver.current = new ResizeObserver(function(elementsObserved) {
      callback(elementsObserved[0])
    })
  }

  function unobserve(observedCurrent) {
    resizeObserver.current.unobserve(observedCurrent)
  }

  useLayoutEffect(
    () => {
      if ('ResizeObserver' in window) {
        const observedCurrent = observedElement && observedElement.current

        if (observedCurrent) {
          observe(observedElement.current)
        }

        if (resizeObserver.current && observedCurrent) {
          resizeObserver.current.observe(observedCurrent)
        }

        return () => {
          unobserve(observedCurrent)
        }
      }
    },
    [observedElement, observedData]
  )
}

export default useResizeObserver