Auto Scroll Upward or Downward Through HTML list items children of some element (E.g. Discord web app DM chat)

scrollListItems.js

const ScrollDirection = {
    UP: 'UP',
    DOWN: 'DOWN'
};

function scrollListItems(elementSelector, scrollDirection) {
    let parentElement = document.querySelector(elementSelector);

    if (parentElement) {
        let listItems = parentElement.querySelectorAll('li');
        if (listItems.length === 0) {
            console.log('No list items found.');
            return;
        }

        // Jump to end of list
        const itemToScroll = scrollDirection === ScrollDirection.UP ? listItems[0] : listItems[listItems.length - 1];
        itemToScroll.scrollIntoView({ behavior: 'smooth', block: 'start' });
    } else {
        console.log('parent element not found.');
    }
}

scrollChatUp = () => scrollListItems('main[class^=chatContent]', ScrollDirection.UP);
scrollChatDown = () => scrollListItems('main[class^=chatContent]', ScrollDirection.DOWN);