Avoid dynamic dispatch for scheduler calls

Author: gaearon

packages/react-art/src/ReactARTHostConfig.js

@@ -5,22 +5,24 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {
-  unstable_scheduleCallback as scheduleDeferredCallback,
-  unstable_cancelCallback as cancelDeferredCallback,
-} from 'scheduler';
-export {
-  unstable_now as now,
-  unstable_scheduleCallback as scheduleDeferredCallback,
-  unstable_shouldYield as shouldYield,
-  unstable_cancelCallback as cancelDeferredCallback,
-} from 'scheduler';
 import Transform from 'art/core/transform';
 import Mode from 'art/modes/current';
+import * as Scheduler from 'scheduler';
 import invariant from 'shared/invariant';
 
 import {TYPES, EVENT_TYPES, childrenAsString} from './ReactARTInternals';
 
+// Intentionally not named imports because Rollup would
+// use dynamic dispatch for CommonJS interop named imports.
+const {
+  unstable_now: now,
+  unstable_scheduleCallback: scheduleDeferredCallback,
+  unstable_shouldYield: shouldYield,
+  unstable_cancelCallback: cancelDeferredCallback,
+} = Scheduler;
+
+export {now, scheduleDeferredCallback, shouldYield, cancelDeferredCallback};
+
 const pooledTransform = new Transform();
 
 const NO_CONTEXT = {};

packages/react-cache/src/LRU.js

@@ -7,7 +7,11 @@
  * @flow
  */
 
-import {unstable_scheduleCallback as scheduleCallback} from 'scheduler';
+import * as Scheduler from 'scheduler';
+
+// Intentionally not named imports because Rollup would
+// use dynamic dispatch for CommonJS interop named imports.
+const {unstable_scheduleCallback: scheduleCallback} = Scheduler;
 
 type Entry<T> = {|
   value: T,

packages/react-dom/src/client/ReactDOMHostConfig.js

@@ -7,6 +7,8 @@
  * @flow
  */
 
+import * as Scheduler from 'scheduler';
+
 import {precacheFiberNode, updateFiberProps} from './ReactDOMComponentTree';
 import {
   createElement,
@@ -70,17 +72,18 @@ export type ChildSet = void; // Unused
 export type TimeoutHandle = TimeoutID;
 export type NoTimeout = -1;
 
-import {
-  unstable_scheduleCallback as scheduleDeferredCallback,
-  unstable_cancelCallback as cancelDeferredCallback,
-} from 'scheduler';
 import {enableSuspenseServerRenderer} from 'shared/ReactFeatureFlags';
-export {
-  unstable_now as now,
-  unstable_scheduleCallback as scheduleDeferredCallback,
-  unstable_shouldYield as shouldYield,
-  unstable_cancelCallback as cancelDeferredCallback,
-} from 'scheduler';
+
+// Intentionally not named imports because Rollup would
+// use dynamic dispatch for CommonJS interop named imports.
+const {
+  unstable_now: now,
+  unstable_scheduleCallback: scheduleDeferredCallback,
+  unstable_shouldYield: shouldYield,
+  unstable_cancelCallback: cancelDeferredCallback,
+} = Scheduler;
+
+export {now, scheduleDeferredCallback, shouldYield, cancelDeferredCallback};
 
 let SUPPRESS_HYDRATION_WARNING;
 if (__DEV__) {

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -17,16 +17,7 @@ import {
   __subscriberRef,
   unstable_wrap as Scheduler_tracing_wrap,
 } from 'scheduler/tracing';
-import {
-  unstable_next as Scheduler_next,
-  unstable_getCurrentPriorityLevel as getCurrentPriorityLevel,
-  unstable_runWithPriority as runWithPriority,
-  unstable_ImmediatePriority as ImmediatePriority,
-  unstable_UserBlockingPriority as UserBlockingPriority,
-  unstable_NormalPriority as NormalPriority,
-  unstable_LowPriority as LowPriority,
-  unstable_IdlePriority as IdlePriority,
-} from 'scheduler';
+import * as Scheduler from 'scheduler';
 import {
   invokeGuardedCallback,
   hasCaughtError,
@@ -181,6 +172,19 @@ export type Thenable = {
   then(resolve: () => mixed, reject?: () => mixed): mixed,
 };
 
+// Intentionally not named imports because Rollup would
+// use dynamic dispatch for CommonJS interop named imports.
+const {
+  unstable_next: Scheduler_next,
+  unstable_getCurrentPriorityLevel: getCurrentPriorityLevel,
+  unstable_runWithPriority: runWithPriority,
+  unstable_ImmediatePriority: ImmediatePriority,
+  unstable_UserBlockingPriority: UserBlockingPriority,
+  unstable_NormalPriority: NormalPriority,
+  unstable_LowPriority: LowPriority,
+  unstable_IdlePriority: IdlePriority,
+} = Scheduler;
+
 const {ReactCurrentDispatcher, ReactCurrentOwner} = ReactSharedInternals;
 
 let didWarnAboutStateTransition;

packages/react/src/ReactSharedInternals.js

@@ -6,35 +6,8 @@
  */
 
 import assign from 'object-assign';
-import {
-  unstable_cancelCallback,
-  unstable_shouldYield,
-  unstable_now,
-  unstable_scheduleCallback,
-  unstable_runWithPriority,
-  unstable_next,
-  unstable_getFirstCallbackNode,
-  unstable_pauseExecution,
-  unstable_continueExecution,
-  unstable_wrapCallback,
-  unstable_getCurrentPriorityLevel,
-  unstable_IdlePriority,
-  unstable_ImmediatePriority,
-  unstable_LowPriority,
-  unstable_NormalPriority,
-  unstable_UserBlockingPriority,
-} from 'scheduler';
-import {
-  __interactionsRef,
-  __subscriberRef,
-  unstable_clear,
-  unstable_getCurrent,
-  unstable_getThreadID,
-  unstable_subscribe,
-  unstable_trace,
-  unstable_unsubscribe,
-  unstable_wrap,
-} from 'scheduler/tracing';
+import * as Scheduler from 'scheduler';
+import * as SchedulerTracing from 'scheduler/tracing';
 import ReactCurrentDispatcher from './ReactCurrentDispatcher';
 import ReactCurrentOwner from './ReactCurrentOwner';
 import ReactDebugCurrentFrame from './ReactDebugCurrentFrame';
@@ -53,35 +26,8 @@ if (__UMD__) {
   // This re-export is only required for UMD bundles;
   // CJS bundles use the shared NPM package.
   Object.assign(ReactSharedInternals, {
-    Scheduler: {
-      unstable_cancelCallback,
-      unstable_shouldYield,
-      unstable_now,
-      unstable_scheduleCallback,
-      unstable_runWithPriority,
-      unstable_next,
-      unstable_wrapCallback,
-      unstable_getFirstCallbackNode,
-      unstable_pauseExecution,
-      unstable_continueExecution,
-      unstable_getCurrentPriorityLevel,
-      unstable_IdlePriority,
-      unstable_ImmediatePriority,
-      unstable_LowPriority,
-      unstable_NormalPriority,
-      unstable_UserBlockingPriority,
-    },
-    SchedulerTracing: {
-      __interactionsRef,
-      __subscriberRef,
-      unstable_clear,
-      unstable_getCurrent,
-      unstable_getThreadID,
-      unstable_subscribe,
-      unstable_trace,
-      unstable_unsubscribe,
-      unstable_wrap,
-    },
+    Scheduler,
+    SchedulerTracing,
   });
 }