Track JS bundle parse time as a Sentry span on Android HybridApp

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: elirangoshen

src/setup/telemetry/index.ts

@@ -1,8 +1,8 @@
 import * as Sentry from '@sentry/react-native';
 import {Platform} from 'react-native';
-import performance, {PerformanceObserver} from 'react-native-performance';
+import {PerformanceObserver} from 'react-native-performance';
 import {isDevelopment} from '@libs/Environment/Environment';
-import {endSpan, getSpan, startSpan} from '@libs/telemetry/activeSpans';
+import {endSpan, startSpan} from '@libs/telemetry/activeSpans';
 import {breadcrumbsIntegration, browserProfilingIntegration, consoleIntegration, navigationIntegration, tracingIntegration} from '@libs/telemetry/integrations';
 import processBeforeSendTransactions from '@libs/telemetry/middlewares';
 import CONFIG from '@src/CONFIG';
@@ -41,33 +41,28 @@ export default function (): void {
         op: CONST.TELEMETRY.SPAN_APP_STARTUP,
     });
 
-    const runJsBundleStartEntries = performance.getEntriesByName('runJsBundleStart');
-    if (runJsBundleStartEntries.length > 0) {
-        const jsParseStartSecs = (runJsBundleStartEntries.at(0)?.startTime ?? 0) / 1000;
-
-        startSpan(CONST.TELEMETRY.SPAN_JS_PARSE_TIME, {
-            name: CONST.TELEMETRY.SPAN_JS_PARSE_TIME,
-            op: CONST.TELEMETRY.SPAN_JS_PARSE_TIME,
-            startTime: jsParseStartSecs,
-            parentSpan: getSpan(CONST.TELEMETRY.SPAN_APP_STARTUP),
-        });
-
-        const finishJsParseSpan = (endTimeSecs: number) => {
-            endSpan(CONST.TELEMETRY.SPAN_JS_PARSE_TIME, endTimeSecs);
-        };
-
-        const runJsBundleEndEntries = performance.getEntriesByName('runJsBundleEnd');
-        if (runJsBundleEndEntries.length > 0) {
-            finishJsParseSpan((runJsBundleEndEntries.at(0)?.startTime ?? 0) / 1000);
-        } else {
-            const observer = new PerformanceObserver((list) => {
-                const entries = list.getEntriesByName('runJsBundleEnd');
-                if (entries.length > 0) {
-                    finishJsParseSpan((entries.at(0)?.startTime ?? 0) / 1000);
-                    observer.disconnect();
-                }
-            });
-            observer.observe({type: 'mark', buffered: true});
+    // getEntriesByName() queries the JS-side entry store, which is only populated after
+    // CONTENT_APPEARED fires (emitBufferedMarks). Since this code runs during JS bundle
+    // execution — before content appears — the sync check always returns [].
+    // Use a PerformanceObserver with type 'react-native-mark' (native marks arrive as
+    // PerformanceReactNativeMark, not PerformanceMark) and buffered: true so it fires
+    // when CONTENT_APPEARED flushes the native mark buffer to JS.
+    let jsParseStartMs: number | undefined;
+    const observer = new PerformanceObserver((list) => {
+        for (const entry of list.getEntries()) {
+            if (entry.name === 'runJsBundleStart' && jsParseStartMs === undefined) {
+                jsParseStartMs = entry.startTime;
+                startSpan(CONST.TELEMETRY.SPAN_JS_PARSE_TIME, {
+                    name: CONST.TELEMETRY.SPAN_JS_PARSE_TIME,
+                    op: CONST.TELEMETRY.SPAN_JS_PARSE_TIME,
+                    startTime: jsParseStartMs / 1000,
+                });
+            }
+            if (entry.name === 'runJsBundleEnd' && jsParseStartMs !== undefined) {
+                endSpan(CONST.TELEMETRY.SPAN_JS_PARSE_TIME, entry.startTime / 1000);
+                observer.disconnect();
+            }
         }
-    }
+    });
+    observer.observe({type: 'react-native-mark', buffered: true});
 }