@primer/react/dist/hooks/useScrollFlash.js

An implementation of GitHub's Primer Design System using React

import { c } from 'react-compiler-runtime';
import { useEffect } from 'react';

/**
 * This hook will flash the scrollbars for a ref of a container that has scrollable overflow
 * @param scrollContainerRef The ref of the scrollable content
 */
function useScrollFlash(scrollContainerRef) {
  const $ = c(3);
  let t0;
  let t1;
  if ($[0] !== scrollContainerRef) {
    t0 = () => {
      const scrollContainer = scrollContainerRef.current;
      if (!scrollContainer) {
        return;
      }
      const currentScroll = scrollContainer.scrollTop;
      const maxScroll = scrollContainer.scrollHeight;
      const altScroll = currentScroll < Math.min(1, maxScroll) ? currentScroll + 1 : currentScroll - 1;
      scrollContainer.scrollTop = altScroll;
      scrollContainer.scrollTop = currentScroll;
    };
    t1 = [scrollContainerRef];
    $[0] = scrollContainerRef;
    $[1] = t0;
    $[2] = t1;
  } else {
    t0 = $[1];
    t1 = $[2];
  }
  useEffect(t0, t1);
}

export { useScrollFlash as default };