Define reportError in the Jest preset so React does not mask errors on Node 26

Author: ahmdshrif

packages/jest-preset/jest/__tests__/setup-test.js

@@ -8,6 +8,8 @@
  * @format
  */
 
+import * as React from 'react';
+
 const NativeExceptionsManager = jest.requireMock(
   'react-native/Libraries/Core/NativeExceptionsManager',
 ).default;
@@ -54,3 +56,28 @@ test('native component mocks work with a partial react-native mock', () => {
     }).not.toThrow();
   });
 });
+
+test('reportError is defined so React does not mistake this for a DOM', () => {
+  // `window` is aliased to `global`, so React only avoids constructing and
+  // dispatching a DOM `ErrorEvent` (which this environment cannot do) when
+  // `reportError` is available.
+  // $FlowFixMe[prop-missing] - `reportError` is not in Flow's global defs.
+  expect(typeof global.reportError).toBe('function');
+});
+
+test('an error thrown in a transition is reported unchanged', () => {
+  const error = new Error('Original error');
+  const handler = jest.fn();
+
+  process.on('uncaughtException', handler);
+
+  try {
+    React.startTransition(() => {
+      throw error;
+    });
+  } finally {
+    process.off('uncaughtException', handler);
+  }
+
+  expect(handler).toHaveBeenCalledWith(error);
+});

packages/jest-preset/jest/setup.js

@@ -55,6 +55,21 @@ Object.defineProperties(global, {
     value: jest.requireActual<unknown>('regenerator-runtime/runtime'),
     writable: true,
   },
+  // `window` is aliased to `global` below, so React's `reportGlobalError`
+  // treats this environment as a DOM as soon as Node exposes an `ErrorEvent`
+  // global (Node >= 26 does), and then calls `window.dispatchEvent`, which
+  // does not exist here. The resulting `TypeError` replaces whatever error
+  // React was trying to report. Defining `reportError` keeps React on a code
+  // path that works: like `window.reportError` on the web, it reports the
+  // error as if it were uncaught, which in Node means `uncaughtException`.
+  reportError: {
+    configurable: true,
+    enumerable: true,
+    value(error: unknown): void {
+      process.emit('uncaughtException', error);
+    },
+    writable: true,
+  },
   requestAnimationFrame: {
     configurable: true,
     enumerable: true,