adam187
diff --git a/‎packages/replay/src/coreHandlers/handleBeforeSendEvent.ts
Lines changed: 42 additions & 0 deletions b/‎packages/replay/src/coreHandlers/handleBeforeSendEvent.ts
Lines changed: 42 additions & 0 deletions
diff --git a/‎packages/replay/src/replay.ts
Lines changed: 1 addition & 1 deletion b/‎packages/replay/src/replay.ts
Lines changed: 1 addition & 1 deletion
diff --git a/‎packages/replay/src/util/addGlobalListeners.ts
Lines changed: 2 additions & 0 deletions b/‎packages/replay/src/util/addGlobalListeners.ts
Lines changed: 2 additions & 0 deletions
diff --git a/‎packages/replay/test/integration/coreHandlers/handleBeforeSendEvent.test.ts
Lines changed: 80 additions & 0 deletions b/‎packages/replay/test/integration/coreHandlers/handleBeforeSendEvent.test.ts
Lines changed: 80 additions & 0 deletions
@@ -0,0 +1,42 @@
+import type { ErrorEvent, Event } from '@sentry/types';
+
+import type { ReplayContainer } from '../types';
+import { createBreadcrumb } from '../util/createBreadcrumb';
+import { isErrorEvent } from '../util/eventUtils';
+import { addBreadcrumbEvent } from './util/addBreadcrumbEvent';
+
+type BeforeSendEventCallback = (event: Event) => void;
+
+/**
+ * Returns a listener to be added to `client.on('afterSendErrorEvent, listener)`.
+ */
+export function handleBeforeSendEvent(replay: ReplayContainer): BeforeSendEventCallback {
+  return (event: Event) => {
+    if (!replay.isEnabled() || !isErrorEvent(event)) {
+      return;
+    }
+
+    handleHydrationError(replay, event);
+  };
+}
+
+function handleHydrationError(replay: ReplayContainer, event: ErrorEvent): void {
+  const exceptionValue = event.exception && event.exception.values && event.exception.values[0].value;
+  if (typeof exceptionValue !== 'string') {
+    return;
+  }
+
+  if (
+    // Only matches errors in production builds of react-dom
+    // Example https://reactjs.org/docs/error-decoder.html?invariant=423
+    exceptionValue.match(/reactjs\.org\/docs\/error-decoder\.html\?invariant=(418|419|422|423|425)/) ||
+    // Development builds of react-dom
+    // Example Text: content did not match. Server: "A" Client: "B"
+    exceptionValue.match(/(hydration|content does not match|did not match)/i)
+  ) {
+    const breadcrumb = createBreadcrumb({
+      category: 'replay.hydrate-error',
+    });
+    addBreadcrumbEvent(replay, breadcrumb);
+  }
+}
@@ -1,7 +1,7 @@
 /* eslint-disable max-lines */ // TODO: We might want to split this file up
 import { EventType, record } from '@sentry-internal/rrweb';
 import { captureException, getClient, getCurrentHub } from '@sentry/core';
-import type { ReplayRecordingMode, Transaction } from '@sentry/types';
+import type { Event as SentryEvent, ReplayRecordingMode, Transaction } from '@sentry/types';
 import { logger } from '@sentry/utils';
 
 import {
 
@@ -4,6 +4,7 @@ import type { Client, DynamicSamplingContext } from '@sentry/types';
 import { addClickKeypressInstrumentationHandler, addHistoryInstrumentationHandler } from '@sentry/utils';
 
 import { handleAfterSendEvent } from '../coreHandlers/handleAfterSendEvent';
+import { handleBeforeSendEvent } from '../coreHandlers/handleBeforeSendEvent';
 import { handleDomListener } from '../coreHandlers/handleDom';
 import { handleGlobalEventListener } from '../coreHandlers/handleGlobalEvent';
 import { handleHistorySpanListener } from '../coreHandlers/handleHistory';
@@ -35,6 +36,7 @@ export function addGlobalListeners(replay: ReplayContainer): void {
 
   // If a custom client has no hooks yet, we continue to use the "old" implementation
   if (hasHooks(client)) {
+    client.on('beforeSendEvent', handleBeforeSendEvent(replay));
     client.on('afterSendEvent', handleAfterSendEvent(replay));
     client.on('createDsc', (dsc: DynamicSamplingContext) => {
       const replayId = replay.getSessionId();
 
@@ -0,0 +1,80 @@
+import { handleBeforeSendEvent } from '../../../src/coreHandlers/handleBeforeSendEvent';
+import type { ReplayContainer } from '../../../src/replay';
+import { Error } from '../../fixtures/error';
+import { resetSdkMock } from '../../mocks/resetSdkMock';
+import { useFakeTimers } from '../../utils/use-fake-timers';
+
+useFakeTimers();
+let replay: ReplayContainer;
+
+describe('Integration | coreHandlers | handleBeforeSendEvent', () => {
+  afterEach(() => {
+    replay.stop();
+  });
+
+  it('adds a hydration breadcrumb on development hydration error', async () => {
+    ({ replay } = await resetSdkMock({
+      replayOptions: {
+        stickySession: false,
+      },
+      sentryOptions: {
+        replaysSessionSampleRate: 0.0,
+        replaysOnErrorSampleRate: 1.0,
+      },
+    }));
+
+    const handler = handleBeforeSendEvent(replay);
+    const addBreadcrumbSpy = jest.spyOn(replay, 'throttledAddEvent');
+
+    const error = Error();
+    error.exception.values[0].value = 'Text content did not match. Server: "A" Client: "B"';
+    handler(error);
+
+    expect(addBreadcrumbSpy).toHaveBeenCalledTimes(1);
+    expect(addBreadcrumbSpy).toHaveBeenCalledWith({
+      data: {
+        payload: {
+          category: 'replay.hydrate-error',
+          timestamp: expect.any(Number),
+          type: 'default',
+        },
+        tag: 'breadcrumb',
+      },
+      timestamp: expect.any(Number),
+      type: 5,
+    });
+  });
+
+  it('adds a hydration breadcrumb on production hydration error', async () => {
+    ({ replay } = await resetSdkMock({
+      replayOptions: {
+        stickySession: false,
+      },
+      sentryOptions: {
+        replaysSessionSampleRate: 0.0,
+        replaysOnErrorSampleRate: 1.0,
+      },
     }));
+
+    const handler = handleBeforeSendEvent(replay);
+    const addBreadcrumbSpy = jest.spyOn(replay, 'throttledAddEvent');
+
+    const error = Error();
+    error.exception.values[0].value = 'https://reactjs.org/docs/error-decoder.html?invariant=423';
+    handler(error);
+
+    expect(addBreadcrumbSpy).toHaveBeenCalledTimes(1);
+    expect(addBreadcrumbSpy).toHaveBeenCalledWith({
+      data: {
+        payload: {
+          category: 'replay.hydrate-error',
+          timestamp: expect.any(Number),
+          type: 'default',
+        },
+        tag: 'breadcrumb',
+      },
+      timestamp: expect.any(Number),
+      type: 5,
+    });
+  });
+});