mime-chat/src/modules/scroll.ts
2021-03-29 10:15:54 -05:00

50 lines
1,016 B
TypeScript

export default function useScroll(element: string) {
let isScrolledToBottom: boolean;
// Set the initial scroll position.
const setScroll = (smooth: boolean) => {
const view = document.getElementById(element)
if (view) {
view.scrollTo({
top: view.scrollHeight - view.clientHeight,
behavior: (smooth) ? 'smooth' : 'auto'
});
}
}
// Update isScrolledToBottom
const updateScrollRef = () => {
const view = document.getElementById(element)
if (view) {
isScrolledToBottom = view.scrollHeight - view.clientHeight <= view.scrollTop + 1
}
}
// Adjust scroll after we add content to the messenger.
const adjustScroll = () => {
const view = document.getElementById(element)
if (view) {
if (isScrolledToBottom) {
view.scrollTo({
top: view.scrollHeight - view.clientHeight,
behavior: 'smooth'
});
}
}
}
return {
updateScrollRef,
adjustScroll,
setScroll,
}
}