diff --git a/packages/react-dom/src/events/DOMModernPluginEventSystem.js b/packages/react-dom/src/events/DOMModernPluginEventSystem.js
index 61c707bad6a13..b8c07cc4e914f 100644
--- a/packages/react-dom/src/events/DOMModernPluginEventSystem.js
+++ b/packages/react-dom/src/events/DOMModernPluginEventSystem.js
@@ -12,6 +12,7 @@ import type {DOMTopLevelEventType} from 'legacy-events/TopLevelEventTypes';
 import type {EventSystemFlags} from 'legacy-events/EventSystemFlags';
 import type {Fiber} from 'react-reconciler/src/ReactFiber';
 import type {PluginModule} from 'legacy-events/PluginModuleType';
+import type {ReactSyntheticEvent} from 'legacy-events/ReactSyntheticEventType';
 
 import {registrationNameDependencies} from 'legacy-events/EventPluginRegistry';
 import {batchedEventUpdates} from 'legacy-events/ReactGenericBatching';
@@ -102,11 +103,11 @@ function dispatchEventsForPlugins(
   rootContainer: Element | Document,
 ): void {
   const nativeEventTarget = getEventTarget(nativeEvent);
-  const syntheticEvents = [];
+  const syntheticEvents: Array<ReactSyntheticEvent> = [];
 
   for (let i = 0; i < plugins.length; i++) {
     const possiblePlugin: PluginModule<AnyNativeEvent> = plugins[i];
-    if (possiblePlugin) {
+    if (possiblePlugin !== undefined) {
       const extractedEvents = possiblePlugin.extractEvents(
         topLevelType,
         targetInst,
@@ -115,12 +116,13 @@ function dispatchEventsForPlugins(
         eventSystemFlags,
         rootContainer,
       );
-      if (extractedEvents) {
-        if (isArray(extractedEvents)) {
-          syntheticEvents.push(...(extractedEvents: any));
-        } else {
-          syntheticEvents.push(extractedEvents);
-        }
+      if (isArray(extractedEvents)) {
+        // Flow complains about @@iterator being missing in ReactSyntheticEvent,
+        // so we cast to avoid the Flow error.
+        const arrOfExtractedEvents = ((extractedEvents: any): Array<ReactSyntheticEvent>);
+        syntheticEvents.push(...arrOfExtractedEvents);
+      } else if (extractedEvents != null) {
+        syntheticEvents.push(extractedEvents);
       }
     }
   }
diff --git a/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js b/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
index 5a82c1d238237..66c670b7ca3ec 100644
--- a/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
+++ b/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
@@ -13,16 +13,12 @@ let React;
 let ReactFeatureFlags;
 let ReactDOM;
 
-function dispatchEvent(element, type) {
+function dispatchClickEvent(element) {
   const event = document.createEvent('Event');
-  event.initEvent(type, true, true);
+  event.initEvent('click', true, true);
   element.dispatchEvent(event);
 }
 
-function dispatchClickEvent(element) {
-  dispatchEvent(element, 'click');
-}
-
 describe('DOMModernPluginEventSystem', () => {
   let container;
 
diff --git a/packages/react-native-renderer/src/ReactNativeBridgeEventPlugin.js b/packages/react-native-renderer/src/ReactNativeBridgeEventPlugin.js
index 789a4f25061c5..076ef7126aa53 100644
--- a/packages/react-native-renderer/src/ReactNativeBridgeEventPlugin.js
+++ b/packages/react-native-renderer/src/ReactNativeBridgeEventPlugin.js
@@ -34,7 +34,7 @@ const ReactNativeBridgeEventPlugin = {
     nativeEvent: AnyNativeEvent,
     nativeEventTarget: null | Object,
     eventSystemFlags: EventSystemFlags,
-  ): ?Object {
+  ): Object | null {
     if (targetInst == null) {
       // Probably a node belonging to another renderer's tree.
       return null;