27 lines
1.0 KiB
JavaScript
27 lines
1.0 KiB
JavaScript
// Captures a scroll position
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export const getScrollPosition = (el) => {
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return {
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scrollTop: el.scrollTop,
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scrollHeight: el.scrollHeight,
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offsetHeight: el.offsetHeight
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}
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}
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// A helper function that is used to keep the scroll position fixed as the new elements are added to the top
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// Takes two scroll positions, before and after the update.
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export const getNewTopPosition = (previousPosition, newPosition) => {
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return previousPosition.scrollTop + (newPosition.scrollHeight - previousPosition.scrollHeight)
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}
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export const isBottomedOut = (el, offset = 0) => {
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if (!el) { return }
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const scrollHeight = el.scrollTop + offset
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const totalHeight = el.scrollHeight - el.offsetHeight
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return totalHeight <= scrollHeight
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}
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// Height of the scrollable container. The dynamic height is needed to ensure the mobile browser panel doesn't overlap or hide the posting form.
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export const scrollableContainerHeight = (inner, header, footer) => {
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return inner.offsetHeight - header.clientHeight - footer.clientHeight
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}
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