Fork ReactSharedInternals for UMD builds

packages/react/src/ReactSharedInternals.js

@@ -6,8 +6,6 @@
  */
 
 import assign from 'object-assign';
-import * as Scheduler from 'scheduler';
-import * as SchedulerTracing from 'scheduler/tracing';
 import ReactCurrentDispatcher from './ReactCurrentDispatcher';
 import ReactCurrentOwner from './ReactCurrentOwner';
 import ReactDebugCurrentFrame from './ReactDebugCurrentFrame';

packages/react/src/forks/ReactSharedInternals.umd.js

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import assign from 'object-assign';
+import * as Scheduler from 'scheduler';
+import * as SchedulerTracing from 'scheduler/tracing';
+import ReactCurrentDispatcher from '../ReactCurrentDispatcher';
+import ReactCurrentOwner from '../ReactCurrentOwner';
+import ReactDebugCurrentFrame from '../ReactDebugCurrentFrame';
+
+const ReactSharedInternals = {
+  ReactCurrentDispatcher,
+  ReactCurrentOwner,
+  // used by act()
+  ReactShouldWarnActingUpdates: {current: false},
+  // Used by renderers to avoid bundling object-assign twice in UMD bundles:
+  assign,
+};
+
+if (__DEV__) {
+  Object.assign(ReactSharedInternals, {
+    // These should not be included in production.
+    ReactDebugCurrentFrame,
+    // Shim for React DOM 16.0.0 which still destructured (but not used) this.
+    // TODO: remove in React 17.0.
+    ReactComponentTreeHook: {},
+  });
+}
+
+// Re-export the schedule API(s) for UMD bundles.
+// This avoids introducing a dependency on a new UMD global in a minor update,
+// Since that would be a breaking change (e.g. for all existing CodeSandboxes).
+// This re-export is only required for UMD bundles;
+// CJS bundles use the shared NPM package.
+Object.assign(ReactSharedInternals, {
+  Scheduler,
+  SchedulerTracing,
+});
+
+export default ReactSharedInternals;

packages/shared/__tests__/ReactDOMFrameScheduling-test.js

@@ -35,7 +35,7 @@ describe('ReactDOMFrameScheduling', () => {
       };
       spyOnDevAndProd(console, 'error');
       require('react-dom');
-      expect(console.error.calls.count()).toEqual(2);
+      expect(console.error.calls.count()).toEqual(1);
       expect(console.error.calls.argsFor(0)[0]).toMatch(
         "This browser doesn't support requestAnimationFrame.",
       );

scripts/rollup/forks.js

@@ -230,6 +230,17 @@ const forks = Object.freeze({
     }
   },
 
+  'react/src/ReactSharedInternals.js': (bundleType, entry) => {
+    switch (bundleType) {
+      case UMD_DEV:
+      case UMD_PROD:
+      case UMD_PROFILING:
+        return 'react/src/forks/ReactSharedInternals.umd.js';
+      default:
+        return null;
+    }
+  },
+
   // Different wrapping/reporting for caught errors.
   'shared/invokeGuardedCallbackImpl': (bundleType, entry) => {
     switch (bundleType) {