refactor: expose imperative benchmark recorder

Co-authored-by: OpenCode <noreply@opencode.ai>

Author: hi-ogawa

packages/app/src/app.tsx

@@ -20,13 +20,12 @@ import {
 } from "./lib/audio/stem-archive";
 import { encodeWavF32 } from "./lib/audio/wav";
 import { separateInWorker } from "./lib/audio/worker-client";
-import { createBenchmarkRecorder, isBenchmarkMode } from "./lib/benchmark";
+import { benchmark } from "./lib/benchmark";
 import { loadPreferences, savePreferences } from "./lib/preferences";
 import { updateRunProgress, type RunProgress } from "./lib/progress/model";
 import { RunProgressPanel } from "./lib/progress/panel";
 
 export function App() {
-  const benchmarkMode = isBenchmarkMode();
   // synchronize preferences with localStorage
   const [preferences, setPreferences] = useState(loadPreferences);
   useEffect(() => savePreferences(preferences), [preferences]);
@@ -140,7 +139,7 @@ export function App() {
         finalizeMs: 0,
       });
       const started = performance.now();
-      const recordBenchmark = createBenchmarkRecorder(startedAt);
+      benchmark.start(startedAt);
       const request: SeparateRequest = {
         left: decodedAudio.left.slice(),
         right: decodedAudio.right.slice(),
@@ -151,7 +150,7 @@ export function App() {
       };
       const separated = await separateInWorker(request, {
         onProgress: (event, at) => {
-          recordBenchmark?.(event, at);
+          benchmark.record(event, at);
           setRunProgress((progress) =>
             progress ? updateRunProgress(progress, event, at) : progress,
           );
@@ -177,7 +176,7 @@ export function App() {
       return { outputs: nextOutputs, archive, durationMs };
     },
     onSuccess: ({ archive }) => {
-      if (!benchmarkMode) {
+      if (!benchmark.enabled) {
         downloadBlob(archive.url, archive.name);
       }
     },

packages/app/src/lib/benchmark.ts

@@ -19,21 +19,28 @@ interface BenchmarkResult {
   chunks: ChunkTiming[];
 }
 
-export function createBenchmarkRecorder(startedAt: number) {
-  if (!new URLSearchParams(location.search).has("benchmark")) {
-    return null;
-  }
+let progress: RunProgress | null = null;
 
-  delete window.__demucsBenchmarkResult;
-  let progress: RunProgress = {
-    phase: "preparing",
-    startedAt,
-    done: 0,
-    total: 0,
-    models: [],
-    finalizeMs: 0,
-  };
-  return (event: ProgressEvent, at: number) => {
+export const benchmark = {
+  enabled: new URLSearchParams(location.search).has("benchmark"),
+  start(startedAt: number) {
+    if (!this.enabled) {
+      return;
+    }
+    delete window.__demucsBenchmarkResult;
+    progress = {
+      phase: "preparing",
+      startedAt,
+      done: 0,
+      total: 0,
+      models: [],
+      finalizeMs: 0,
+    };
+  },
+  record(event: ProgressEvent, at: number) {
+    if (!progress) {
+      return;
+    }
     progress = updateRunProgress(progress, event, at);
     if (event.type === "finalized") {
       window.__demucsBenchmarkResult = {
@@ -49,10 +56,7 @@ export function createBenchmarkRecorder(startedAt: number) {
         totalMs: at - progress.startedAt,
         chunks: progress.models.flatMap((item) => item.chunkTimings),
       };
+      progress = null;
     }
-  };
-}
-
-export function isBenchmarkMode() {
-  return new URLSearchParams(location.search).has("benchmark");
-}
+  },
+};