Automatic retry for iframe loading (workaround for Google Doc Viewer 204 issue)

GoogleDocFrame.tsx

function GoogleDocFrame({ url }: { url: string }) {
  const frameRef = useRef<HTMLIFrameElement>(null)
  const viewerUrl = `https://docs.google.com/viewer?embedded=true&url=${url}`
  let cancel: () => void | undefined
  useEffect(() => {
    cancel = setFrameSrcWithRetry(frameRef.current!, viewerUrl, true)

    // unmount
    return () => {
      if (cancel) {
        cancel()
      }
    }
  }, [url])
  return <iframe ref={frameRef} />
}

setFrameSrcWithRetry.ts

/**
 * Set src for an iframe. If the iframe does not load, try setting src again to
 *   force reload. Repeat for given number of times.
 * This can be used as a workaround for Google doc viewer 204 issue: https://tinyurl.com/y7zx253q
 * Viewer URL pattern: [https://docs.google.com/viewer?embedded=true&url=PUBLIC_URL]
 * @param iframe
 * @param src
 * @param maxRetries - Max number of time to try frame reload
 * @param initialDelayMs - Initial delay time to use. Exponential easing is used
 *  for additional cycles.
 */

export default function setFrameSrcWithRetry(
  iframe: HTMLIFrameElement,
  src: string,
  maxRetries = 4,
  initialDelayMs = 3000) {
  console.log('setting frame source')

  let retriesLeft = maxRetries
  let loaded = false
  let timeoutRef: any = null
  let delayMs = initialDelayMs

  const cancel = () => {
    retriesLeft = 0
    if (timeoutRef) {
      clearTimeout(timeoutRef)
    }
  }

  const setRetry = () => {
    setTimeout(() => {
      if (!loaded && retriesLeft-- > 0) {
        log.info('forcing iframe refresh')
        iframe.src = src
        setRetry()
        delayMs *= 1.5
      }
    }, delayMs)
  }

  iframe.onload = () => {
    loaded = true
    cancel()
  }
  iframe.src = src
  setRetry()

  return cancel
}

I think server overload will result in 204 respond, as this is an undocumented feature from Google, we can't expect that much :(
If your pdf support CORS, I'd say using pdf.js for a better viewer