Support non-dev builds in development environment

packages/react-reconciler/src/ReactFiberAct.js

@@ -45,10 +45,7 @@ export function isConcurrentActEnvironment(): void | boolean {
           IS_REACT_ACT_ENVIRONMENT
         : undefined;
 
-    if (
-      !isReactActEnvironmentGlobal &&
-      ReactSharedInternals.actQueue !== null
-    ) {
+    if (!isReactActEnvironmentGlobal && ReactSharedInternals.actQueue) {
       // TODO: Include link to relevant documentation page.
       console.error(
         'The current testing environment is not configured to support ' +

packages/react-reconciler/src/ReactFiberErrorLogger.js

@@ -169,7 +169,7 @@ export function logUncaughtError(
       errorBoundaryName = null;
     }
     const error = (errorInfo.value: any);
-    if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+    if (__DEV__ && ReactSharedInternals.actQueue) {
       // For uncaught errors inside act, we track them on the act and then
       // rethrow them into the test.
       ReactSharedInternals.thrownErrors.push(error);

packages/react-reconciler/src/ReactFiberRootScheduler.js

@@ -125,7 +125,7 @@ export function ensureRootIsScheduled(root: FiberRoot): void {
 
   // At the end of the current event, go through each of the roots and ensure
   // there's a task scheduled for each one at the correct priority.
-  if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+  if (__DEV__ && ReactSharedInternals.actQueue) {
     // We're inside an `act` scope.
     if (!didScheduleMicrotask_act) {
       didScheduleMicrotask_act = true;
@@ -394,7 +394,7 @@ function scheduleTaskForRootDuringMicrotask(
       // on the `act` queue.
       !(
         __DEV__ &&
-        ReactSharedInternals.actQueue !== null &&
+        ReactSharedInternals.actQueue &&
         existingCallbackNode !== fakeActCallbackNode
       )
     ) {
@@ -555,7 +555,7 @@ function scheduleCallback(
   priorityLevel: PriorityLevel,
   callback: RenderTaskFn,
 ) {
-  if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+  if (__DEV__ && ReactSharedInternals.actQueue) {
     // Special case: We're inside an `act` scope (a testing utility).
     // Instead of scheduling work in the host environment, add it to a
     // fake internal queue that's managed by the `act` implementation.
@@ -576,7 +576,7 @@ function cancelCallback(callbackNode: mixed) {
 }
 
 function scheduleImmediateRootScheduleTask() {
-  if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+  if (__DEV__ && ReactSharedInternals.actQueue) {
     // Special case: Inside an `act` scope, we push microtasks to the fake `act`
     // callback queue. This is because we currently support calling `act`
     // without awaiting the result. The plan is to deprecate that, and require

packages/react-reconciler/src/ReactFiberThenable.js

@@ -102,7 +102,7 @@ export function trackUsedThenable<T>(
   thenable: Thenable<T>,
   index: number,
 ): T {
-  if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+  if (__DEV__ && ReactSharedInternals.actQueue) {
     ReactSharedInternals.didUsePromise = true;
   }
   const trackedThenables = getThenablesFromState(thenableState);

packages/react-reconciler/src/ReactFiberWorkLoop.js

@@ -2677,7 +2677,7 @@ function renderRootConcurrent(root: FiberRoot, lanes: Lanes) {
         }
       }
 
-      if (__DEV__ && ReactSharedInternals.actQueue !== null) {
+      if (__DEV__ && ReactSharedInternals.actQueue) {
         // `act` special case: If we're inside an `act` scope, don't consult
         // `shouldYield`. Always keep working until the render is complete.
         // This is not just an optimization: in a unit test environment, we
@@ -4637,7 +4637,7 @@ function scheduleCallback(priorityLevel: any, callback) {
     // If we're currently inside an `act` scope, bypass Scheduler and push to
     // the `act` queue instead.
     const actQueue = ReactSharedInternals.actQueue;
-    if (actQueue !== null) {
+    if (actQueue) {
       actQueue.push(callback);
       return fakeActCallbackNode;
     } else {
@@ -4651,7 +4651,7 @@ function scheduleCallback(priorityLevel: any, callback) {
 
 function shouldForceFlushFallbacksInDEV() {
   // Never force flush in production. This function should get stripped out.
-  return __DEV__ && ReactSharedInternals.actQueue !== null;
+  return __DEV__ && !!ReactSharedInternals.actQueue;
 }
 
 function warnIfUpdatesNotWrappedWithActDEV(fiber: Fiber): void {

packages/react/src/ReactAct.js

@@ -46,8 +46,9 @@ export function act<T>(callback: () => T | Thenable<T>): Thenable<T> {
     const prevActQueue = ReactSharedInternals.actQueue;
     const prevActScopeDepth = actScopeDepth;
     actScopeDepth++;
-    const queue = (ReactSharedInternals.actQueue =
-      prevActQueue !== null ? prevActQueue : []);
+    const queue = (ReactSharedInternals.actQueue = prevActQueue
+      ? prevActQueue
+      : []);
     // Used to reproduce behavior of `batchedUpdates` in legacy mode. Only
     // set to `true` while the given callback is executed, not for updates
     // triggered during an async event, because this is how the legacy