Unread Divider Comments Block for Svelte

Edit PEOPLE and REMARKS (an id, who wrote it, who it answers in to, an ISO at and the body), ME for the person using the page and LAST_VISIT with its printed text. A comment is new when its at is after LAST_VISIT, so nothing else needs flagging. In a real app LAST_VISIT comes from the server, per person and per thread.

It measures the divider against the top of the scroll region and scrolls the region to it, smoothly unless the visitor prefers reduced motion, then focuses the divider so a keyboard user arrives there. After the divider is on screen, the button changes to a count of new comments below the visible part and scrolls to the end. When nothing is new it says "Nothing new" and stays in place, because the button never disappears.

What you have seen. Mark as seen only changes the page. To make it real, send the id of the newest comment you have read from the Mark as seen handler (or from a scroll-based read marker), store it per person and thread, and send it back as LAST_VISIT next time. Nothing refreshes on its own here; a live thread would add new comments to the end and update the count.

It filters the list to comments that answer ME, and the divider moves to the first new reply, with its own count. If none of those replies is new, the divider is not drawn. The region keeps its height in every case, and an empty filter shows a plain sentence in the same space.

The thread is a labelled scroll region you can reach with Tab and scroll with the arrow keys. The divider is a list item with a visible sentence, and the New badge is a word, not a colour. The toggle group names the filter, the buttons name their action, and a polite status line reports every change. Times use a machine-readable date and stay left to right inside a right-to-left page.

The two buttons stack at full width above the thread, and the filter drops under the sentence. The thread keeps its height and scrolls inside its region, so the page never grows with a long conversation.