Add behind feature flag

Author: trueadm

packages/react-dom/src/events/ReactDOMUpdateBatching.js

@@ -9,6 +9,7 @@ import {
   needsStateRestore,
   restoreStateIfNeeded,
 } from './ReactDOMControlledComponent';
+import {enableDiscreteEventFlushingChange} from 'shared/ReactFeatureFlags';
 
 // Used as a way to call batchedUpdates when we don't have a reference to
 // the renderer. Such as when we're dispatching events or if third party
@@ -89,24 +90,31 @@ export function discreteUpdates(fn, a, b, c, d) {
 
 let lastFlushedEventTimeStamp = 0;
 export function flushDiscreteUpdatesIfNeeded(timeStamp: number) {
-  // event.timeStamp isn't overly reliable due to inconsistencies in
-  // how different browsers have historically provided the time stamp.
-  // Some browsers provide high-resolution time stamps for all events,
-  // some provide low-resolution time stamps for all events. FF < 52
-  // even mixes both time stamps together. Some browsers even report
-  // negative time stamps or time stamps that are 0 (iOS9) in some cases.
-  // Given we are only comparing two time stamps with equality (!==),
-  // we are safe from the resolution differences. If the time stamp is 0
-  // we bail-out of preventing the flush, which can affect semantics,
-  // such as if an earlier flush removes or adds event listeners that
-  // are fired in the subsequent flush. However, this is the same
-  // behaviour as we had before this change, so the risks are low.
-  if (
-    !isInsideEventHandler &&
-    (timeStamp === 0 || lastFlushedEventTimeStamp !== timeStamp)
-  ) {
-    lastFlushedEventTimeStamp = timeStamp;
-    flushDiscreteUpdatesImpl();
+  if (enableDiscreteEventFlushingChange) {
+    // event.timeStamp isn't overly reliable due to inconsistencies in
+    // how different browsers have historically provided the time stamp.
+    // Some browsers provide high-resolution time stamps for all events,
+    // some provide low-resolution time stamps for all events. FF < 52
+    // even mixes both time stamps together. Some browsers even report
+    // negative time stamps or time stamps that are 0 (iOS9) in some cases.
+    // Given we are only comparing two time stamps with equality (!==),
+    // we are safe from the resolution differences. If the time stamp is 0
+    // we bail-out of preventing the flush, which can affect semantics,
+    // such as if an earlier flush removes or adds event listeners that
+    // are fired in the subsequent flush. However, this is the same
+    // behaviour as we had before this change, so the risks are low.
+    if (
+      !isInsideEventHandler &&
+      (timeStamp === 0 || lastFlushedEventTimeStamp !== timeStamp)
+    ) {
+      lastFlushedEventTimeStamp = timeStamp;
+      flushDiscreteUpdatesImpl();
+    }
+  } else {
+    if (!isInsideEventHandler) {
+      lastFlushedEventTimeStamp = timeStamp;
+      flushDiscreteUpdatesImpl();
+    }
   }
 }
 

packages/shared/ReactFeatureFlags.js

@@ -125,3 +125,5 @@ export const deferRenderPhaseUpdateToNextBatch = true;
 
 // Replacement for runWithPriority in React internals.
 export const decoupleUpdatePriorityFromScheduler = false;
+
+export const enableDiscreteEventFlushingChange = false;

packages/shared/forks/ReactFeatureFlags.native-fb.js

@@ -48,6 +48,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.native-oss.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.test-renderer.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.test-renderer.native.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.test-renderer.www.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.testing.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = false;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.testing.www.js

@@ -47,6 +47,7 @@ export const enableFilterEmptyStringAttributesDOM = false;
 export const enableNewReconciler = false;
 export const deferRenderPhaseUpdateToNextBatch = true;
 export const decoupleUpdatePriorityFromScheduler = false;
+export const enableDiscreteEventFlushingChange = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.www.js

@@ -75,6 +75,8 @@ export const disableTextareaChildren = __EXPERIMENTAL__;
 
 export const warnUnstableRenderSubtreeIntoContainer = false;
 
+export const enableDiscreteEventFlushingChange = true;
+
 // Enable forked reconciler. Piggy-backing on the "variant" global so that we
 // don't have to add another test dimension. The build system will compile this
 // to the correct value.