a bit more deduplication

Author: Lms24

packages/browser-utils/src/metrics/cls.ts

@@ -17,7 +17,7 @@ import {
 import { DEBUG_BUILD } from '../debug-build';
 import { addClsInstrumentationHandler } from './instrument';
 import type { WebVitalReportEvent } from './utils';
-import { msToSec, startStandaloneWebVitalSpan } from './utils';
+import { msToSec, startStandaloneWebVitalSpan, supportsWebVital } from './utils';
 import { onHidden } from './web-vitals/lib/onHidden';
 import { runOnce } from './web-vitals/lib/runOnce';
 
@@ -35,7 +35,7 @@ export function trackClsAsStandaloneSpan(): void {
   let standaloneClsEntry: LayoutShift | undefined;
   let pageloadSpanId: string | undefined;
 
-  if (!supportsLayoutShift()) {
+  if (!supportsWebVital('layout-shift')) {
     return;
   }
 
@@ -139,11 +139,3 @@ function sendStandaloneClsSpan(
     span.end(startTime);
   }
 }
-
-function supportsLayoutShift(): boolean {
-  try {
-    return PerformanceObserver.supportedEntryTypes.includes('layout-shift');
-  } catch {
-    return false;
-  }
-}

packages/browser-utils/src/metrics/lcp.ts

@@ -17,7 +17,7 @@ import {
 import { DEBUG_BUILD } from '../debug-build';
 import { addLcpInstrumentationHandler } from './instrument';
 import type { WebVitalReportEvent } from './utils';
-import { msToSec, startStandaloneWebVitalSpan } from './utils';
+import { msToSec, startStandaloneWebVitalSpan, supportsWebVital } from './utils';
 import { onHidden } from './web-vitals/lib/onHidden';
 import { runOnce } from './web-vitals/lib/runOnce';
 
@@ -35,7 +35,7 @@ export function trackLcpAsStandaloneSpan(): void {
   let standaloneLcpEntry: LargestContentfulPaint | undefined;
   let pageloadSpanId: string | undefined;
 
-  if (!supportsLargestContentfulPaint()) {
+  if (!supportsWebVital('largest-contentful-paint')) {
     return;
   }
 
@@ -151,11 +151,3 @@ export function _sendStandaloneLcpSpan(
     span.end(startTime);
   }
 }
-
-function supportsLargestContentfulPaint(): boolean {
-  try {
-    return PerformanceObserver.supportedEntryTypes.includes('largest-contentful-paint');
-  } catch {
-    return false;
-  }
-}

packages/browser-utils/src/metrics/utils.ts

@@ -170,3 +170,14 @@ export function extractNetworkProtocol(nextHopProtocol: string): { name: string;
   }
   return { name, version };
 }
+
+/**
+ * Generic support check for web vitals
+ */
+export function supportsWebVital(entryType: 'layout-shift' | 'largest-contentful-paint'): boolean {
+  try {
+    return PerformanceObserver.supportedEntryTypes.includes(entryType);
+  } catch {
+    return false;
+  }
+}