Skip to content

Improve Roles page UX and app-wide scroll performance #63

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
cursor merged 1 commit into from
Aug 10, 2026
Merged

Improve Roles page UX and app-wide scroll performance #63

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
94 changes: 20 additions & 74 deletions apps/ui/src/components/PageSectionNav.tsx
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,14 +1,14 @@
import { useEffect, useRef, useState } from "react";
import { useEffect, useState } from "react";

export type SectionNavItem = {
id: string;
label: string;
};

/**
* Sticky “On this page” links with active-section highlighting.
* Scroll tracking avoids layout thrashing: use IntersectionObserver entry
* geometry only, coalesce updates to animation frames, and skip no-op sets.
* Sticky “On this page” links. Active state is click/hash driven only —
* no IntersectionObserver scroll-spy (that was a major source of scroll jank
* on long pages, especially in WebView).
*/
export function PageSectionNav({
items,
Expand All @@ -19,89 +19,35 @@ export function PageSectionNav({
}) {
const [activeId, setActiveId] = useState(items[0]?.id ?? "");
const sectionKey = items.map((item) => item.id).join("|");
const clickLockUntil = useRef(0);
const itemsRef = useRef(items);
itemsRef.current = items;

useEffect(() => {
const first = sectionKey.split("|")[0];
if (first) setActiveId(first);
const ids = sectionKey.split("|").filter(Boolean);
const fromHash = window.location.hash.replace(/^#/, "");
if (fromHash && ids.includes(fromHash)) {
setActiveId(fromHash);
return;
}
if (ids[0]) setActiveId(ids[0]);
}, [sectionKey]);

useEffect(() => {
const ids = sectionKey.split("|").filter(Boolean);
const nodes = ids
.map((id) => document.getElementById(id))
.filter((el): el is HTMLElement => Boolean(el));
if (nodes.length === 0) return;

const ratios = new Map<string, number>();
const tops = new Map<string, number>();
let raf = 0;

const commit = () => {
raf = 0;
if (Date.now() < clickLockUntil.current) return;

const ordered = itemsRef.current;
let bestId = "";
let bestRatio = 0;
for (const item of ordered) {
const ratio = ratios.get(item.id) ?? 0;
if (ratio > bestRatio) {
bestRatio = ratio;
bestId = item.id;
}
}
if (bestId && bestRatio > 0.02) {
setActiveId((prev) => (prev === bestId ? prev : bestId));
return;
}

let aboveId = "";
let aboveTop = -Infinity;
for (const item of ordered) {
const top = tops.get(item.id);
if (top == null) continue;
if (top <= 140 && top >= aboveTop) {
aboveTop = top;
aboveId = item.id;
}
}
if (aboveId) setActiveId((prev) => (prev === aboveId ? prev : aboveId));
};

const observer = new IntersectionObserver(
(entries) => {
for (const entry of entries) {
const id = entry.target.id;
ratios.set(id, entry.isIntersecting ? entry.intersectionRatio : 0);
// Prefer observer-provided rect — do not call getBoundingClientRect (forces layout).
tops.set(id, entry.boundingClientRect.top);
}
if (!raf) raf = requestAnimationFrame(commit);
},
{
root: null,
rootMargin: "-10% 0px -55% 0px",
// Fewer thresholds → fewer callbacks while scrolling.
threshold: [0, 0.25, 0.6, 1],
},
);

for (const node of nodes) observer.observe(node);
return () => {
if (raf) cancelAnimationFrame(raf);
observer.disconnect();
const ids = new Set(sectionKey.split("|").filter(Boolean));
const onHash = () => {
const id = window.location.hash.replace(/^#/, "");
if (id && ids.has(id)) setActiveId(id);
};
window.addEventListener("hashchange", onHash);
return () => window.removeEventListener("hashchange", onHash);
}, [sectionKey]);

function goTo(id: string) {
const el = document.getElementById(id);
if (!el) return;
clickLockUntil.current = Date.now() + 700;
setActiveId(id);
const reduceMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
// Update hash without fighting smooth scroll (replaceState avoids hashchange jump).
const url = `${window.location.pathname}${window.location.search}#${id}`;
window.history.replaceState(null, "", url);
el.scrollIntoView({ behavior: reduceMotion ? "auto" : "smooth", block: "start" });
}

Expand Down
Loading