component/textarea-caret-position: xy coordinates of a textarea or input's caret
→ github.com/component/textarea-caret-position
Caret position on screen for placing menus and other autocomplete popups near the cursor.
Tagged javascript
Intersection Observer API - Web APIs | MDN
→ developer.mozilla.org/en-US/docs/Web/API/Intersection_Observ…
Perhaps this could help with infinite scrolling.