Render cached feeds before recommendation refresh

js/app/feedCoordinator.js

@@ -1016,8 +1016,21 @@ export function createFeedCoordinator(deps) {
 
       const recommendationFeed =
         feedType === FEED_TYPES.FOR_YOU || feedType === FEED_TYPES.EXPLORE;
+      let exploreActivation = null;
       if (recommendationFeed && typeof this.ensureExploreDataService === "function") {
-        await this.ensureExploreDataService();
+        // Recommendation indexes are an enhancement, not a prerequisite for
+        // showing cached videos.  Activating the worker here used to leave a
+        // returning For You view stuck on its static loading markup whenever
+        // worker startup was slow or unavailable.
+        exploreActivation = Promise.resolve(this.ensureExploreDataService()).catch(
+          (error) => {
+            devLogger.warn(
+              `[Application] Recommendation data activation failed for ${feedType}:`,
+              error,
+            );
+            return null;
+          },
+        );
       } else if (this.exploreDataService?.setActive) {
         this.exploreDataService.setActive(false);
       }
@@ -1117,6 +1130,23 @@ export function createFeedCoordinator(deps) {
       if (this.videoListView) {
         this.videoListView.state.videosMap = this.videosMap;
       }
+
+      // Re-score once the optional recommendation indexes are ready, but only
+      // if the user is still looking at this feed. The first render above is
+      // deliberately cache-first and must not wait for worker startup.
+      if (exploreActivation) {
+        void exploreActivation.then(() => {
+          if (!this.isFeedActive(feedType)) {
+            return;
+          }
+          return this.refreshFeed(feedType, { reason: "recommendation-data-ready" });
+        }).catch((error) => {
+          devLogger.warn(
+            `[Application] Failed to refresh ${feedType} after recommendation data activation:`,
+            error,
+          );
+        });
+      }
     },
 
     /**

tests/app/feedCoordinator.test.mjs

@@ -85,3 +85,61 @@ test('createFeedCoordinator - loadForYouVideos', async (t) => {
       assert.strictEqual(app.videoSubscription, 'mock-subscription', 'Should update videoSubscription');
   });
 });
+
+test("loadForYouVideos renders without waiting for recommendation worker activation", async () => {
+  let resolveActivation;
+  const activation = new Promise((resolve) => {
+    resolveActivation = resolve;
+  });
+  let loadVideosStarted = false;
+  const mockDeps = {
+    devLogger: { log: mock.fn(), warn: mock.fn() },
+    userLogger: { warn: mock.fn() },
+    nostrClient: {},
+    getSidebarLoadingMarkup: mock.fn(() => '<div>Loading...</div>'),
+    watchHistoryService: {},
+    subscriptions: {},
+    createActiveNostrSource: mock.fn(),
+    createBlacklistFilterStage: mock.fn(),
+    createDisinterestFilterStage: mock.fn(),
+    createDedupeByRootStage: mock.fn(),
+    createExploreDiversitySorter: mock.fn(),
+    createExploreScorerStage: mock.fn(),
+    createKidsAudienceFilterStage: mock.fn(),
+    createKidsScorerStage: mock.fn(),
+    createKidsScoreSorter: mock.fn(),
+    createModerationStage: mock.fn(),
+    createResolvePostedAtStage: mock.fn(),
+    createTagPreferenceFilterStage: mock.fn(),
+    createWatchHistorySuppressionStage: mock.fn(),
+    createChronologicalSorter: mock.fn(),
+    createSubscriptionAuthorsSource: mock.fn(),
+    registerWatchHistoryFeed: mock.fn(),
+  };
+  const coordinator = createFeedCoordinator(mockDeps);
+  const app = {
+    ...coordinator,
+    nostrService: {
+      getFilteredActiveVideos: mock.fn(() => [{ id: "cached" }]),
+      loadVideos: mock.fn(async ({ onVideos }) => {
+        loadVideosStarted = true;
+        onVideos([{ id: "cached", title: "Cached", created_at: 1 }], { reason: "cache" });
+        return [{ id: "cached", title: "Cached", created_at: 1 }];
+      }),
+      getVideoSubscription: mock.fn(() => null),
+      getVideosMap: mock.fn(() => new Map()),
+    },
+    videoListView: { state: {}, render: mock.fn() },
+    mountVideoListView: mock.fn(() => ({ innerHTML: "" })),
+    checkRelayHealthWarning: mock.fn(),
+    setFeedTelemetryContext: mock.fn(),
+    isAuthorBlocked: mock.fn(() => false),
+    refreshFeed: mock.fn(async () => {}),
+    ensureExploreDataService: mock.fn(() => activation),
+    blacklistedEventIds: new Set(),
+  };
+
+  await app.loadForYouVideos(false);
+  assert.equal(loadVideosStarted, true);
+  resolveActivation();
+});