Add transaction op default

CHANGELOG.md

@@ -6,6 +6,9 @@
 
 - Add `lastEventId` method to the API ([#2675](https://github.com/getsentry/sentry-react-native/pull/2675))
 
+### Fix
+- `Sentry.startTransaction` doesn't require `op` ([#2691](https://github.com/getsentry/sentry-react-native/pull/2691))
+
 ### Dependencies
 
 - Bump Cocoa SDK from v7.31.2 to v7.31.3 ([#2647](https://github.com/getsentry/sentry-react-native/pull/2647))

src/js/measurements.ts

@@ -28,7 +28,7 @@ export function _addTracingExtensions(): void {
   }
 }
 
-type StartTransactionFunction = (
+export type StartTransactionFunction = (
   this: Hub,
   transactionContext: TransactionContext,
   customSamplingContext?: CustomSamplingContext
@@ -48,6 +48,10 @@ const _patchStartTransaction = (
     transactionContext: TransactionContext,
     customSamplingContext?: CustomSamplingContext
   ): Transaction {
+    if (!transactionContext.op) {
+      transactionContext.op = 'default';
+    }
+
     const transaction: Transaction = originalStartTransaction.apply(this, [
       transactionContext,
       customSamplingContext,

test/measurements.test.ts

@@ -0,0 +1,27 @@
+import { getCurrentHub,getMainCarrier } from '@sentry/core';
+
+import { _addTracingExtensions, StartTransactionFunction } from '../src/js/measurements';
+
+describe('Tracing extensions', () => {
+  test('transaction has default op', async () => {
+    _addTracingExtensions();
+    const hub = getCurrentHub();
+    const carrier = getMainCarrier();
+    const startTransaction = carrier.__SENTRY__?.extensions?.startTransaction as StartTransactionFunction | undefined;
+
+    const transaction = startTransaction?.apply(hub, [{}]);
+
+    expect(transaction).toEqual(expect.objectContaining({ op: 'default' }));
+  });
+
+  test('transaction does not overwrite custom op', async () => {
+    _addTracingExtensions();
+    const hub = getCurrentHub();
+    const carrier = getMainCarrier();
+    const startTransaction = carrier.__SENTRY__?.extensions?.startTransaction as StartTransactionFunction | undefined;
+
+    const transaction = startTransaction?.apply(hub, [{ op: 'custom' }]);
+
+    expect(transaction).toEqual(expect.objectContaining({ op: 'custom' }));
+  });
+});