React hook to detect scroll direction, based on the API of https://github.com/dollarshaveclub/scrolldir

useScrollDirection.js

const SCROLL_UP = "up";
const SCROLL_DOWN = "down";

const useScrollDirection = ({
  initialDirection,
  thresholdPixels,
  off
} = {}) => {
  const [scrollDir, setScrollDir] = useState(initialDirection);

  useEffect(() => {
    const threshold = thresholdPixels || 0;
    let lastScrollY = window.pageYOffset;
    let ticking = false;

    const updateScrollDir = () => {
      const scrollY = window.pageYOffset;

      if (Math.abs(scrollY - lastScrollY) < threshold) {
        // We haven't exceeded the threshold
        ticking = false;
        return;
      }

      setScrollDir(scrollY > lastScrollY ? SCROLL_DOWN : SCROLL_UP);
      lastScrollY = scrollY > 0 ? scrollY : 0;
      ticking = false;
    };

    const onScroll = () => {
      if (!ticking) {
        window.requestAnimationFrame(updateScrollDir);
        ticking = true;
      }
    };

    /**
     * Bind the scroll handler if `off` is set to false.
     * If `off` is set to true reset the scroll direction.
     */
    !off
      ? window.addEventListener("scroll", onScroll)
      : setScrollDir(initialDirection);

    return () => window.removeEventListener("scroll", onScroll);
  }, [initialDirection, thresholdPixels, off]);

  return scrollDir;
};

I'm noticing something a bit weird.

I use this hook in a Gatsbyjs project and when I do a standard refresh (ctrl+r), the scroll direction is determined as up but when I do a hard refresh (ctrl+shift+r), the scroll direction is determined as down.

I use Brave browser so chromium engine. I would expect same output whether regular refresh or hard refresh before any user input scrolling has occurred.
Any thoughts on why this might be happening or if anyone else has noticed this?

Either way, appreciate the gist!

I'm using this hook for a Next.js project with server side rendering, similar to Gatsby. The issue is probably due to the discrepancy between SSR and CSR. Try adding a default for SSR when there is no window available, i.e.:

 if (!process.browser) return SCROLL_UP; 

Try this -

Install this package from npm - https://www.npmjs.com/package/react-use-scroll-direction

Then Detect Scroll Direction : - )

import React from 'react'
import { useScrollDirection } from 'react-use-scroll-direction'

export const Window_Scroll_Direction = () => {
  const [direction, setDirection] = React.useState(String)
  const { isScrollingUp, isScrollingDown } = useScrollDirection()

  React.useEffect(() => {
    isScrollingDown && setDirection('down')
    isScrollingUp && setDirection('up')
  }, [isScrollingDown, isScrollingUp])

  return (
    <>
      <div className="fixed top-0 bg-white">
        {direction === 'down' ? 'Scrolling down' : 'scrolling up'}
      </div>
    </>
  )
}