@n0n3br/react-use-scroll-direction
Version:
A robust React hook to detect vertical scroll direction ('up', 'down', 'static') for any DOM element or the window.
72 lines (71 loc) • 2.43 kB
JavaScript
// src/index.ts
import { useState, useEffect, useRef, useCallback } from "react";
function useScrollDirection(ref, options) {
const { threshold = 0, throttleDelay = 100 } = options || {};
const [scrollDirection, setScrollDirection] = useState("static");
const lastScrollPosition = useRef(0);
const throttleTimeoutId = useRef(null);
const getScrollY = useCallback(() => {
if (ref && ref.current) {
return ref.current.scrollTop;
}
return window.scrollY;
}, [ref]);
useEffect(() => {
const targetElement = ref && ref.current ? ref.current : window;
if (!targetElement)
return;
lastScrollPosition.current = getScrollY();
const handleScroll = () => {
const currentScrollPosition = getScrollY();
const scrollDifference = currentScrollPosition - lastScrollPosition.current;
if (Math.abs(scrollDifference) <= threshold) {
return;
}
if (scrollDifference > 0) {
setScrollDirection("down");
} else {
setScrollDirection("up");
}
lastScrollPosition.current = currentScrollPosition;
};
const throttledHandleScroll = () => {
if (throttleTimeoutId.current === null) {
throttleTimeoutId.current = window.requestAnimationFrame(() => {
handleScroll();
throttleTimeoutId.current = null;
});
}
};
const throttledHandleScrollWithDelay = () => {
if (throttleTimeoutId.current === null) {
throttleTimeoutId.current = window.setTimeout(() => {
handleScroll();
throttleTimeoutId.current = null;
}, throttleDelay);
}
};
const effectiveThrottledScrollHandler = throttleDelay > 0 && throttleDelay !== 100 ? throttledHandleScrollWithDelay : throttledHandleScroll;
targetElement.addEventListener("scroll", effectiveThrottledScrollHandler, {
passive: true
});
return () => {
targetElement.removeEventListener(
"scroll",
effectiveThrottledScrollHandler
);
if (throttleTimeoutId.current !== null) {
if (throttleDelay > 0 && throttleDelay !== 100) {
clearTimeout(throttleTimeoutId.current);
} else {
cancelAnimationFrame(throttleTimeoutId.current);
}
throttleTimeoutId.current = null;
}
};
}, [ref, threshold, throttleDelay, getScrollY]);
return scrollDirection;
}
export {
useScrollDirection
};