web-ui-pack/helpers/onScrollStop.js

Web package with UI elements

export default function onScrollStop(el, listener, options) {
    let { scrollTop: y, scrollLeft: x } = el;
    let id;
    let wasScrolled = false;
    const check = async () => {
        let i = 0;
        while (1) {
            ++i;
            await new Promise((resolve) => (id = requestAnimationFrame(resolve)));
            if (id === null) {
                return;
            }
            const isScrolled = el.scrollTop !== y || el.scrollLeft !== x;
            if (isScrolled) {
                wasScrolled = true;
                y = el.scrollTop;
                x = el.scrollLeft;
                i = 0;
            }
            else if (i === 3) {
                if (wasScrolled || options?.onceNotStarted) {
                    setTimeout(() => listener.call(el));
                    if (options?.once || options?.onceNotStarted) {
                        return;
                    }
                }
                wasScrolled = false;
                i = 0;
            }
        }
    };
    check();
    return () => (id = null);
}