experimental_useEvent (#25229)

This commit adds a new hook `useEvent` per the RFC [here](reactjs/rfcs#220), gated as experimental. 

Co-authored-by: Rick Hanlon <rickhanlonii@gmail.com>
Co-authored-by: Rick Hanlon <rickhanlonii@fb.com>
Co-authored-by: Lauren Tan <poteto@users.noreply.github.com>

packages/react-reconciler/src/ReactFiberCommitWork.new.js

@@ -48,6 +48,7 @@ import {
   enableUpdaterTracking,
   enableCache,
   enableTransitionTracing,
+  enableUseEventHook,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -162,6 +163,7 @@ import {
   Layout as HookLayout,
   Insertion as HookInsertion,
   Passive as HookPassive,
+  Snapshot as HookSnapshot,
 } from './ReactHookEffectTags';
 import {didWarnAboutReassigningProps} from './ReactFiberBeginWork.new';
 import {doesFiberContain} from './ReactFiberTreeReflection';
@@ -407,14 +409,24 @@ function commitBeforeMutationEffectsOnFiber(finishedWork: Fiber) {
 
   if ((flags & Snapshot) !== NoFlags) {
     setCurrentDebugFiberInDEV(finishedWork);
+  }
 
-    switch (finishedWork.tag) {
-      case FunctionComponent:
-      case ForwardRef:
-      case SimpleMemoComponent: {
-        break;
+  switch (finishedWork.tag) {
+    case FunctionComponent: {
+      if (enableUseEventHook) {
+        if ((flags & Update) !== NoFlags) {
+          // useEvent doesn't need to be cleaned up
+          commitHookEffectListMount(HookSnapshot | HookHasEffect, finishedWork);
+        }
       }
-      case ClassComponent: {
+      break;
+    }
+    case ForwardRef:
+    case SimpleMemoComponent: {
+      break;
+    }
+    case ClassComponent: {
+      if ((flags & Snapshot) !== NoFlags) {
         if (current !== null) {
           const prevProps = current.memoizedProps;
           const prevState = current.memoizedState;
@@ -468,29 +480,35 @@ function commitBeforeMutationEffectsOnFiber(finishedWork: Fiber) {
           }
           instance.__reactInternalSnapshotBeforeUpdate = snapshot;
         }
-        break;
       }
-      case HostRoot: {
+      break;
+    }
+    case HostRoot: {
+      if ((flags & Snapshot) !== NoFlags) {
         if (supportsMutation) {
           const root = finishedWork.stateNode;
           clearContainer(root.containerInfo);
         }
-        break;
       }
-      case HostComponent:
-      case HostText:
-      case HostPortal:
-      case IncompleteClassComponent:
-        // Nothing to do for these component types
-        break;
-      default: {
+      break;
+    }
+    case HostComponent:
+    case HostText:
+    case HostPortal:
+    case IncompleteClassComponent:
+      // Nothing to do for these component types
+      break;
+    default: {
+      if ((flags & Snapshot) !== NoFlags) {
         throw new Error(
           'This unit of work tag should not have side-effects. This error is ' +
             'likely caused by a bug in React. Please file an issue.',
         );
       }
     }
+  }
 
+  if ((flags & Snapshot) !== NoFlags) {
     resetCurrentDebugFiberInDEV();
   }
 }

packages/react-reconciler/src/ReactFiberCommitWork.old.js

@@ -48,6 +48,7 @@ import {
   enableUpdaterTracking,
   enableCache,
   enableTransitionTracing,
+  enableUseEventHook,
 } from 'shared/ReactFeatureFlags';
 import {
   FunctionComponent,
@@ -162,6 +163,7 @@ import {
   Layout as HookLayout,
   Insertion as HookInsertion,
   Passive as HookPassive,
+  Snapshot as HookSnapshot,
 } from './ReactHookEffectTags';
 import {didWarnAboutReassigningProps} from './ReactFiberBeginWork.old';
 import {doesFiberContain} from './ReactFiberTreeReflection';
@@ -407,14 +409,24 @@ function commitBeforeMutationEffectsOnFiber(finishedWork: Fiber) {
 
   if ((flags & Snapshot) !== NoFlags) {
     setCurrentDebugFiberInDEV(finishedWork);
+  }
 
-    switch (finishedWork.tag) {
-      case FunctionComponent:
-      case ForwardRef:
-      case SimpleMemoComponent: {
-        break;
+  switch (finishedWork.tag) {
+    case FunctionComponent: {
+      if (enableUseEventHook) {
+        if ((flags & Update) !== NoFlags) {
+          // useEvent doesn't need to be cleaned up
+          commitHookEffectListMount(HookSnapshot | HookHasEffect, finishedWork);
+        }
       }
-      case ClassComponent: {
+      break;
+    }
+    case ForwardRef:
+    case SimpleMemoComponent: {
+      break;
+    }
+    case ClassComponent: {
+      if ((flags & Snapshot) !== NoFlags) {
         if (current !== null) {
           const prevProps = current.memoizedProps;
           const prevState = current.memoizedState;
@@ -468,29 +480,35 @@ function commitBeforeMutationEffectsOnFiber(finishedWork: Fiber) {
           }
           instance.__reactInternalSnapshotBeforeUpdate = snapshot;
         }
-        break;
       }
-      case HostRoot: {
+      break;
+    }
+    case HostRoot: {
+      if ((flags & Snapshot) !== NoFlags) {
         if (supportsMutation) {
           const root = finishedWork.stateNode;
           clearContainer(root.containerInfo);
         }
-        break;
       }
-      case HostComponent:
-      case HostText:
-      case HostPortal:
-      case IncompleteClassComponent:
-        // Nothing to do for these component types
-        break;
-      default: {
+      break;
+    }
+    case HostComponent:
+    case HostText:
+    case HostPortal:
+    case IncompleteClassComponent:
+      // Nothing to do for these component types
+      break;
+    default: {
+      if ((flags & Snapshot) !== NoFlags) {
         throw new Error(
           'This unit of work tag should not have side-effects. This error is ' +
             'likely caused by a bug in React. Please file an issue.',
         );
       }
     }
+  }
 
+  if ((flags & Snapshot) !== NoFlags) {
     resetCurrentDebugFiberInDEV();
   }
 }