perf(ui): render only a bounded window around the focused row

src/pages/Feed/FeedPage.tsx

@@ -107,6 +107,30 @@ function FeedPage() {
 		focusedOnMore() ? undefined : episodes()[focusedEpIdx()];
 	const curLen = () => rowCount();
 
+	// ── Render window ────────────────────────────────────────────────────────
+	// The union grows to thousands of episodes after repeated fetch-more
+	// presses; rendering every row per frame froze the UI. Render only a
+	// bounded slice around the focus (real indexes preserved) — the scrollbox
+	// still keeps the focused row in view. Spacers above/below the window
+	// restore the full content height so the scrollbar tracks the real list.
+	// Each EpisodeRow is 3 lines tall (title, subtitle, date).
+	const LIST_WINDOW = 30;
+	const ROW_HEIGHT = 3;
+	const listWindow = createMemo<[number, number]>(() => {
+		const len = episodes().length;
+		// Focusing the Fetch More button keeps the window anchored at the
+		// last episode — no jump when the focus crosses onto the button.
+		const f = focusedOnMore() ? len - 1 : focusedEpIdx();
+		return [
+			Math.max(0, f - LIST_WINDOW),
+			Math.min(len, f + LIST_WINDOW + 1),
+		];
+	});
+	const visibleEpisodes = createMemo(() => {
+		const [start, end] = listWindow();
+		return episodes().slice(start, end);
+	});
+
 	const ensureFocus = () => {
 		if (rowCount() > 0 && focus() >= rowCount())
 			nav.setDepthFocus(rowCount() - 1, 0);
@@ -245,17 +269,22 @@ function FeedPage() {
 							</text>
 						}
 					>
-						<LoadingIndicator label="Refreshing…" />
+						<LoadingIndicator />
 					</Show>
 				</box>
 			}
 		>
-			<For each={episodes()}>
+			{/* Spacers keep the scrollbox content at the FULL list height so
+			    the scrollbar reflects the real list, not the render window. */}
+			<Show when={listWindow()[0] > 0}>
+				<box height={listWindow()[0] * ROW_HEIGHT} />
+			</Show>
+			<For each={visibleEpisodes()}>
 				{(item, index) => (
 					<EpisodeRow
 						episode={item.episode}
 						subtitle={() => item.feed.customName || item.feed.podcast.title}
-						index={index}
+						index={() => listWindow()[0] + index()}
 						focused={focusedEpIdx}
 						active={isActive}
 						selected={() => nav.isSelected(item.episode.id)}
@@ -264,11 +293,14 @@ function FeedPage() {
 						marker={marker}
 						onMouseDown={() => {
 							nav.setActivePane(DEPTH_CENTER_PANE);
-							nav.setDepthFocus(index(), 0);
+							nav.setDepthFocus(listWindow()[0] + index(), 0);
 						}}
 					/>
 				)}
 			</For>
+			<Show when={episodes().length - listWindow()[1] > 0}>
+				<box height={(episodes().length - listWindow()[1]) * ROW_HEIGHT} />
+			</Show>
 			<Show when={showFetchMore()}>
 				<FetchMoreRow
 					index={() => episodes().length}
@@ -286,7 +318,7 @@ function FeedPage() {
 			</Show>
 			<Show when={feedStore.isLoadingFeeds()}>
 				<box alignItems="center" paddingTop={1}>
-					<LoadingIndicator label="Refreshing…" />
+					<LoadingIndicator />
 				</box>
 			</Show>
 		</Show>

src/pages/MyShows/MyShowsPage.tsx

@@ -89,13 +89,23 @@ function ShowRow(props: {
 			backgroundColor={bg()}
 			onMouseDown={props.onMouseDown}
 		>
-			<text fg={fg()}>{isFocused() ? props.marker() : " "}</text>
-			<text fg={fg()}>{props.title}</text>
-			<text fg={isFocused() ? theme.surface : muted()}>
+			<text flexShrink={0} fg={fg()}>
+				{isFocused() ? props.marker() : " "}
+			</text>
+			{/* Long titles truncate with middle-ellipsis instead of wrapping —
+			    a wrapped title grows the row to 2+ lines and shifts every row
+			    below (see EpisodeList for the same guard). The episode-count
+			    and watchlist cells are flexShrink=0 so they never shrink or
+			    wrap; the flexible title takes the remaining width. */}
+			<text wrapMode="none" truncate fg={fg()}>
+				{props.title}
+			</text>
+			<text flexShrink={0} fg={isFocused() ? theme.surface : muted()}>
 				({props.feed.episodes.length})
 			</text>
 			<Show when={props.wlScope()}>
 				<text
+					flexShrink={0}
 					fg={
 						isFocused()
 							? theme.surface
@@ -312,6 +322,30 @@ export function MyShowsPage() {
 	const focusedEpisode = () =>
 		focusedOnMore() ? undefined : episodes()[focusedEpIdx()];
 
+	// ── Render window ────────────────────────────────────────────────────────
+	// The drilled show's list grows deep after repeated fetch-more presses;
+	// rendering every row per frame froze the UI. Render only a bounded slice
+	// around the focus (real indexes preserved) — the scrollbox still keeps
+	// the focused row in view. Spacers above/below the window restore the
+	// full content height so the scrollbar tracks the real list.
+	// Each episode row is 2 lines tall (title, date) — no subtitle here.
+	const LIST_WINDOW = 30;
+	const ROW_HEIGHT = 2;
+	const listWindow = createMemo<[number, number]>(() => {
+		const len = episodes().length;
+		// Focusing the Fetch More button keeps the window anchored at the
+		// last episode — no jump when the focus crosses onto the button.
+		const f = focusedOnMore() ? len - 1 : focusedEpIdx();
+		return [
+			Math.max(0, f - LIST_WINDOW),
+			Math.min(len, f + LIST_WINDOW + 1),
+		];
+	});
+	const visibleEpisodes = createMemo(() => {
+		const [start, end] = listWindow();
+		return episodes().slice(start, end);
+	});
+
 	const curLen = () => (depth() === 0 ? depth0Count() : rowCount());
 
 	const ensureFocus = () => {
@@ -537,9 +571,17 @@ export function MyShowsPage() {
 							paddingRight={1}
 							backgroundColor={focused() ? theme.border : undefined}
 						>
-							<text fg={fg()}>{focused() ? marker() : " "}</text>
-							<text fg={fg()}>{showTitle(feed)}</text>
-							<text fg={muted()}>({feed.episodes.length})</text>
+							<text flexShrink={0} fg={fg()}>
+								{focused() ? marker() : " "}
+							</text>
+							{/* 20%-wide parent pane truncates hard — same
+							    middle-ellipsis guard as the depth-0 rows. */}
+							<text wrapMode="none" truncate fg={fg()}>
+								{showTitle(feed)}
+							</text>
+							<text flexShrink={0} fg={muted()}>
+								({feed.episodes.length})
+							</text>
 						</box>
 					);
 				}}
@@ -622,11 +664,17 @@ export function MyShowsPage() {
 						</box>
 					}
 				>
-					<For each={episodes()}>
+					{/* Spacers keep the scrollbox content at the FULL list
+					    height so the scrollbar reflects the real list, not the
+					    render window. */}
+					<Show when={listWindow()[0] > 0}>
+						<box height={listWindow()[0] * ROW_HEIGHT} />
+					</Show>
+					<For each={visibleEpisodes()}>
 						{(ep, index) => (
 							<EpisodeRow
 								episode={ep}
-								index={index}
+								index={() => listWindow()[0] + index()}
 								focused={focusedEpIdx}
 								active={isActive}
 								selected={() => nav.isSelected(ep.id)}
@@ -635,11 +683,14 @@ export function MyShowsPage() {
 								marker={marker}
 								onMouseDown={() => {
 									nav.setActivePane(DEPTH_CENTER_PANE);
-									nav.setDepthFocus(index(), 1);
+									nav.setDepthFocus(listWindow()[0] + index(), 1);
 								}}
 							/>
 						)}
 					</For>
+					<Show when={episodes().length - listWindow()[1] > 0}>
+						<box height={(episodes().length - listWindow()[1]) * ROW_HEIGHT} />
+					</Show>
 					<Show when={showFetchMore()}>
 						<FetchMoreRow
 							index={() => episodes().length}

tests/show-row-wrap.test.tsx

@@ -0,0 +1,189 @@
+/**
+ * Show-row height regression — My Shows depth-0 rows must stay exactly one
+ * line tall: marker + show title + episode count (+ watchlist dot). The
+ * flexible title carries `wrapMode="none"` + `truncate` (middle-ellipsis:
+ * head and tail of the title stay visible) and the fixed-width cells carry
+ * `flexShrink={0}`, so Yoga can never shrink them and wrap the row — a
+ * wrapped row grows to 2+ lines and the episode count + watchlist dot shift
+ * below the title while scrolling (the original bug). Same guard for the
+ * 20%-wide parent-pane shows list at depth ≥1.
+ *
+ * Rendered at 70 columns so the 35-col current pane / 14-col parent pane are
+ * narrow enough to force truncation on the long title; at the default
+ * 100-col/50-col pane the same rows show everything in full.
+ */
+
+import { describe, test, expect, afterAll } from "bun:test";
+import type { JSX } from "solid-js";
+import { testRender } from "@opentui/solid";
+import { ThemeProvider } from "../src/context/ThemeContext";
+import { PaneRow } from "../src/components/PaneRow";
+
+type Frame = { cols: number; lines: { spans: { text: string }[] }[] };
+
+function frameText(spans: Frame): string[] {
+	return spans.lines.map((l) => l.spans.map((s) => s.text).join(""));
+}
+
+const LONG_TITLE =
+	"Out of Whiskey and Reaching for the Rotgut (Members Only #338)";
+
+// The exact depth-0 row shape MyShowsPage renders: marker + title + count +
+// watchlist dot. Static text, no store hooks — pure layout probe.
+const ShowRowFixed = () => (
+	<box flexDirection="row" gap={1} paddingRight={1}>
+		<text flexShrink={0}>❯</text>
+		<text wrapMode="none" truncate>
+			{LONG_TITLE}
+		</text>
+		<text flexShrink={0}>(123)</text>
+		<text flexShrink={0}>●</text>
+	</box>
+);
+
+// Pre-fix shape: no wrapMode/truncate/flexShrink props — the long title
+// wraps at the shrunken width and pushes the count + dot onto wrapped lines.
+const ShowRowNaive = () => (
+	<box flexDirection="row" gap={1} paddingRight={1}>
+		<text>❯</text>
+		<text>{LONG_TITLE}</text>
+		<text>(123)</text>
+		<text>●</text>
+	</box>
+);
+
+// The depth-1 parent-pane shows-list row (marker + title + count).
+const ParentRowFixed = () => (
+	<box flexDirection="row" gap={1} paddingRight={1}>
+		<text flexShrink={0}>❯</text>
+		<text wrapMode="none" truncate>
+			{LONG_TITLE}
+		</text>
+		<text flexShrink={0}>(123)</text>
+	</box>
+);
+
+const ParentRowNaive = () => (
+	<box flexDirection="row" gap={1} paddingRight={1}>
+		<text>❯</text>
+		<text>{LONG_TITLE}</text>
+		<text>(123)</text>
+	</box>
+);
+
+async function renderRow(
+	row: () => JSX.Element,
+	pane: "current" | "parent",
+	width = 70,
+): Promise<{ lines: string[]; destroy: () => Promise<void> }> {
+	const setup = await testRender(
+		() => (
+			<ThemeProvider mode="dark">
+				<PaneRow
+					parent={pane === "parent" ? row : null}
+					current={pane === "current" ? row : null}
+					preview={null}
+					currentLabel="List"
+				/>
+			</ThemeProvider>
+		),
+		{ width, height: 10, useThread: false },
+	);
+	// ThemeProvider mounts children only once the theme resolves; poll for
+	// the header row so the captured frame is a mounted PaneRow.
+	let lines: string[] | null = null;
+	for (let i = 0; i < 40 && !lines; i++) {
+		await setup.renderOnce();
+		const frame = setup.captureSpans() as unknown as Frame;
+		const ls = frameText(frame);
+		if (ls.some((l) => l.includes("List"))) lines = ls;
+		else await new Promise((r) => setTimeout(r, 100));
+	}
+	if (!lines) throw new Error("PaneRow did not render before timeout");
+	return {
+		lines,
+		destroy: async () => {
+			setup.renderer.destroy();
+		},
+	};
+}
+
+const cleanups: (() => void | Promise<void>)[] = [];
+afterAll(async () => {
+	for (const c of cleanups) {
+		try {
+			await c();
+		} catch {
+			// renderer already torn down — ignore
+		}
+	}
+});
+
+describe("show row height in the current pane (70-wide → 35-col pane)", () => {
+	test("long title stays on one line — middle-ellipsis keeps head AND tail, count + dot stay aligned", async () => {
+		const { lines, destroy } = await renderRow(ShowRowFixed, "current");
+		cleanups.push(destroy);
+
+		// Middle-ellipsis: the title head and its tail both survive, on a
+		// single line (end-truncation would drop the tail).
+		expect(lines.filter((l) => l.includes("Out of Wh"))).toHaveLength(1);
+		expect(lines.filter((l) => l.includes("#338)"))).toHaveLength(1);
+		// The count and watchlist dot sit on that same line — nothing wrapped.
+		const aligned = lines.filter(
+			(l) =>
+				l.includes("Out of Wh") &&
+				l.includes("#338)") &&
+				l.includes("(123)") &&
+				l.includes("●"),
+		);
+		expect(aligned).toHaveLength(1);
+		// Row occupies exactly 1 content line below the header.
+		const content = lines.filter(
+			(l) => l.includes("Out of Wh") || l.includes("(123)"),
+		);
+		expect(content).toHaveLength(1);
+	});
+
+	test("naive row (pre-fix props) wraps the title — the regression the test guards", async () => {
+		const { lines, destroy } = await renderRow(ShowRowNaive, "current");
+		cleanups.push(destroy);
+
+		// The title's wrapped fragments span 3 frame lines instead of 1 —
+		// every row below shifts while scrolling.
+		const titleFragments = lines.filter(
+			(l) =>
+				l.includes("Out of Whiskey") ||
+				l.includes("Rotgut") ||
+				l.includes("#338)"),
+		);
+		expect(titleFragments).toHaveLength(3);
+	});
+});
+
+describe("show row in the parent pane (70-wide → 14-col pane)", () => {
+	test("long title stays on one line with count aligned", async () => {
+		const { lines, destroy } = await renderRow(ParentRowFixed, "parent");
+		cleanups.push(destroy);
+
+		// The 14-col slot truncates the title to a head stub (too narrow for
+		// head + tail), but the row stays one line and the count pins to it.
+		expect(lines.filter((l) => l.includes("O..."))).toHaveLength(1);
+		expect(
+			lines.filter((l) => l.includes("O...") && l.includes("(123)")),
+		).toHaveLength(1);
+	});
+
+	test("naive parent row wraps the title — the regression the test guards", async () => {
+		const { lines, destroy } = await renderRow(ParentRowNaive, "parent");
+		cleanups.push(destroy);
+
+		const titleFragments = lines.filter(
+			(l) =>
+				l.includes("Out of") ||
+				l.includes("Whiskey") ||
+				l.includes("Rotgut") ||
+				l.includes("#3"),
+		);
+		expect(titleFragments.length).toBeGreaterThan(1);
+	});
+});