27 lines
940 B
JavaScript
27 lines
940 B
JavaScript
// Captures a scroll position
|
|
export const getScrollPosition = () => {
|
|
return {
|
|
scrollTop: window.scrollY,
|
|
scrollHeight: document.documentElement.scrollHeight,
|
|
offsetHeight: window.innerHeight,
|
|
}
|
|
}
|
|
|
|
// A helper function that is used to keep the scroll position fixed as the new elements are added to the top
|
|
// Takes two scroll positions, before and after the update.
|
|
export const getNewTopPosition = (previousPosition, newPosition) => {
|
|
return (
|
|
previousPosition.scrollTop +
|
|
(newPosition.scrollHeight - previousPosition.scrollHeight)
|
|
)
|
|
}
|
|
|
|
export const isBottomedOut = (offset = 0) => {
|
|
const scrollHeight = window.scrollY + offset
|
|
const totalHeight = document.documentElement.scrollHeight - window.innerHeight
|
|
return totalHeight <= scrollHeight
|
|
}
|
|
// Returns whether or not the scrollbar is visible.
|
|
export const isScrollable = () => {
|
|
return document.documentElement.scrollHeight > window.innerHeight
|
|
}
|