feat(ttid): Add support for measuring Time to Initial Display for already seen routes

CHANGELOG.md

@@ -13,6 +13,15 @@
 - Add thread information to spans ([#4579](https://github.com/getsentry/sentry-react-native/pull/4579))
 - Exposed `getDataFromUri` as a public API to retrieve data from a URI ([#4638](https://github.com/getsentry/sentry-react-native/pull/4638))
 - Improve Warm App Start reporting on Android ([#4641](https://github.com/getsentry/sentry-react-native/pull/4641))
+- Add support for measuring Time to Initial Display for already seen routes ([#4661](https://github.com/getsentry/sentry-react-native/pull/4661))
+  - Introduce `enableTimeToInitialDisplayForPreloadedRoutes` option to the React Navigation integration.
+
+  ```js
+  Sentry.reactNavigationIntegration({
+    enableTimeToInitialDisplayForPreloadedRoutes: true,
+  });
+  ```
+
 - Add experimental flags `enableExperimentalViewRenderer` and `enableFastViewRendering` to enable up to 5x times more performance in Session Replay on iOS ([#4660](https://github.com/getsentry/sentry-react-native/pull/4660))
 
   ```js

packages/core/src/js/tracing/reactnavigation.ts

@@ -62,6 +62,14 @@ interface ReactNavigationIntegrationOptions {
    * @default true
    */
   ignoreEmptyBackNavigationTransactions: boolean;
+
+  /**
+   * Enabled measuring Time to Initial Display for routes that are already loaded in memory.
+   * (a.k.a., Routes that the navigation integration has already seen.)
+   *
+   * @default false
+   */
+  enableTimeToInitialDisplayForPreloadedRoutes: boolean;
 }
 
 /**
@@ -76,6 +84,7 @@ export const reactNavigationIntegration = ({
   routeChangeTimeoutMs = 1_000,
   enableTimeToInitialDisplay = false,
   ignoreEmptyBackNavigationTransactions = true,
+  enableTimeToInitialDisplayForPreloadedRoutes = false,
 }: Partial<ReactNavigationIntegrationOptions> = {}): Integration & {
   /**
    * Pass the ref to the navigation container to register it to the instrumentation
@@ -268,16 +277,19 @@ export const reactNavigationIntegration = ({
     }
 
     const routeHasBeenSeen = recentRouteKeys.includes(route.key);
-    const latestTtidSpan =
-      !routeHasBeenSeen &&
-      enableTimeToInitialDisplay &&
-      startTimeToInitialDisplaySpan({
+    const startTtidForNewRoute = enableTimeToInitialDisplay && !routeHasBeenSeen;
+    const startTtidForAllRoutes = enableTimeToInitialDisplay && enableTimeToInitialDisplayForPreloadedRoutes;
+
+    let latestTtidSpan: Span | undefined = undefined;
+    if (startTtidForNewRoute || startTtidForAllRoutes) {
+      latestTtidSpan = startTimeToInitialDisplaySpan({
         name: `${route.name} initial display`,
         isAutoInstrumented: true,
       });
+    }
 
     const navigationSpanWithTtid = latestNavigationSpan;
-    if (!routeHasBeenSeen && latestTtidSpan) {
+    if (latestTtidSpan) {
       newScreenFrameEventEmitter?.onceNewFrame(({ newFrameTimestampInSeconds }: NewFrameEvent) => {
         const activeSpan = getActiveSpan();
         if (activeSpan && manualInitialDisplaySpans.has(activeSpan)) {

packages/core/test/tracing/reactnavigation.ttid.test.tsx

@@ -589,6 +589,55 @@ describe('React Navigation - TTID', () => {
     });
   });
 
+  describe('ttid for preloaded/seen routes', () => {
+    beforeEach(() => {
+      jest.useFakeTimers();
+      (notWeb as jest.Mock).mockReturnValue(true);
+      (isHermesEnabled as jest.Mock).mockReturnValue(true);
+    });
+
+    afterEach(() => {
+      jest.useRealTimers();
+    });
+
+    it('should add ttid span and measurement for already seen route', () => {
+      const sut = createTestedInstrumentation({
+        enableTimeToInitialDisplay: true,
+        ignoreEmptyBackNavigationTransactions: false,
+        enableTimeToInitialDisplayForPreloadedRoutes: true,
+      });
+      transportSendMock = initSentry(sut).transportSendMock;
+
+      mockedNavigation = createMockNavigationAndAttachTo(sut);
+
+      jest.runOnlyPendingTimers(); // Flush app start transaction
+      mockedNavigation.navigateToNewScreen();
+      jest.runOnlyPendingTimers(); // Flush navigation transaction
+      mockedNavigation.navigateToInitialScreen();
+      mockedEventEmitter.emitNewFrameEvent();
+      jest.runOnlyPendingTimers(); // Flush navigation transaction
+
+      const transaction = getLastTransaction(transportSendMock);
+      expect(transaction).toEqual(
+        expect.objectContaining<TransactionEvent>({
+          type: 'transaction',
+          spans: expect.arrayContaining([
+            expect.objectContaining<Partial<SpanJSON>>({
+              op: 'ui.load.initial_display',
+              description: 'Initial Screen initial display',
+            }),
+          ]),
+          measurements: expect.objectContaining<Required<TransactionEvent>['measurements']>({
+            time_to_initial_display: {
+              value: expect.any(Number),
+              unit: 'millisecond',
+            },
+          }),
+        }),
+      );
+    });
+  });
+
   function getSpanDurationMs(transaction: TransactionEvent, op: string): number | undefined {
     const ttidSpan = transaction.spans?.find(span => span.op === op);
     if (!ttidSpan) {
@@ -603,10 +652,13 @@ describe('React Navigation - TTID', () => {
     return (spanJSON.timestamp - spanJSON.start_timestamp) * 1000;
   }
 
-  function createTestedInstrumentation(options?: { enableTimeToInitialDisplay?: boolean }) {
+  function createTestedInstrumentation(options?: {
+    enableTimeToInitialDisplay?: boolean
+    enableTimeToInitialDisplayForPreloadedRoutes?: boolean
+    ignoreEmptyBackNavigationTransactions?: boolean
+  }) {
     const sut = Sentry.reactNavigationIntegration({
       ...options,
-      ignoreEmptyBackNavigationTransactions: true, // default true
     });
     return sut;
   }

samples/react-native/src/App.tsx

@@ -53,6 +53,7 @@ const reactNavigationIntegration = Sentry.reactNavigationIntegration({
   routeChangeTimeoutMs: 500, // How long it will wait for the route change to complete. Default is 1000ms
   enableTimeToInitialDisplay: isMobileOs,
   ignoreEmptyBackNavigationTransactions: true,
+  enableTimeToInitialDisplayForPreloadedRoutes: true,
 });
 
 Sentry.init({