fix(ruvocal): keep hidden-tab streams responsive

ruflo/src/ruvocal/src/lib/utils/messageUpdates.spec.ts

@@ -129,6 +129,30 @@ describe("smoothStreamUpdates", () => {
 		expect(delays[0]).toBeGreaterThanOrEqual(delays.at(-1) ?? 0);
 	});
 
+	it("drains stream chunks without timer pacing while the page is hidden", async () => {
+		const source: MessageUpdate[] = [
+			{ type: MessageUpdateType.Stream, token: "one two three four five " },
+		];
+		const delays: number[] = [];
+
+		const updates = await collect(
+			smoothStreamUpdates(fromArray(source), {
+				minDelayMs: 5,
+				maxDelayMs: 80,
+				_internal: {
+					sleep: async (ms: number) => {
+						delays.push(ms);
+					},
+					isPageHidden: () => true,
+					detectChunk: (buffer) => /\S+\s+/.exec(buffer)?.[0] ?? null,
+				},
+			})
+		);
+
+		expect(streamText(updates)).toBe("one two three four five ");
+		expect(delays).toEqual([]);
+	});
+
 	it("handles CJK text correctly", async () => {
 		const source: MessageUpdate[] = [{ type: MessageUpdateType.Stream, token: "你好，世界！" }];
 

ruflo/src/ruvocal/src/lib/utils/messageUpdates.ts

@@ -38,6 +38,7 @@ type SmoothStreamConfig = {
 		now?: () => number;
 		sleep?: (ms: number) => Promise<void>;
 		detectChunk?: ChunkDetector;
+		isPageHidden?: () => boolean;
 	};
 };
 
@@ -168,7 +169,12 @@ export async function* smoothStreamUpdates(
 		maxDelayMs = 80,
 		minRateCharsPerMs = 0.3,
 		maxBufferedMs = 400,
-		_internal: { now = () => performance.now(), sleep = defaultSleep, detectChunk } = {},
+		_internal: {
+			now = () => performance.now(),
+			sleep = defaultSleep,
+			detectChunk,
+			isPageHidden = defaultIsPageHidden,
+		} = {},
 	}: SmoothStreamConfig = {}
 ): AsyncGenerator<MessageUpdate> {
 	const chunkDetector = detectChunk ?? createWordChunkDetector();
@@ -251,7 +257,7 @@ export async function* smoothStreamUpdates(
 			const effectiveMinDelayMs = underBacklogPressure ? 0 : minDelayMs;
 			const delayMs = Math.round(Math.max(effectiveMinDelayMs, Math.min(maxDelayMs, rawDelay)));
 
-			if (delayMs > 0) {
+			if (delayMs > 0 && !isPageHidden()) {
 				await sleep(delayMs);
 			}
 		}
@@ -318,6 +324,8 @@ export const isMessageToolProgressUpdate = (
 
 const defaultSleep = (ms: number): Promise<void> =>
 	new Promise((resolve) => setTimeout(resolve, ms));
+const defaultIsPageHidden = (): boolean =>
+	typeof document !== "undefined" && document.visibilityState === "hidden";
 const waitForEvent = (eventTarget: EventTarget, eventName: string) =>
 	new Promise<boolean>((resolve) =>
 		eventTarget.addEventListener(eventName, () => resolve(true), { once: true })

ruflo/src/ruvocal/src/routes/conversation/[id]/+page.svelte

@@ -249,6 +249,7 @@
 			// Initialize lastUpdateTime outside the loop to persist between updates
 			let lastUpdateTime = new Date();
 			let frameFlushScheduled = false;
+			let frameFlushTimeout: ReturnType<typeof setTimeout> | undefined;
 
 			const flushBuffer = (currentTime: Date) => {
 				if (buffer.length === 0) return;
@@ -261,14 +262,20 @@
 				if (frameFlushScheduled) return;
 				frameFlushScheduled = true;
 				const flush = () => {
+					if (!frameFlushScheduled) return;
 					frameFlushScheduled = false;
+					if (frameFlushTimeout !== undefined) {
+						clearTimeout(frameFlushTimeout);
+						frameFlushTimeout = undefined;
+					}
 					flushBuffer(new Date());
 				};
 				if (typeof requestAnimationFrame === "function") {
 					requestAnimationFrame(flush);
-				} else {
-					setTimeout(flush, 0);
 				}
+				// requestAnimationFrame is suspended in background tabs. Keep a
+				// bounded fallback so buffered tokens still reach the DOM there.
+				frameFlushTimeout = setTimeout(flush, 300);
 			};
 
 			for await (const update of messageUpdatesIterator) {