ModernEventSystem: refine Flow types

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

@@ -7,7 +7,6 @@
  * @flow
  */
 
-import type {DOMTopLevelEventType} from 'legacy-events/TopLevelEventTypes';
 import type {RootType} from './ReactDOMRoot';
 
 import {
@@ -1112,7 +1111,7 @@ export function registerEvent(
   // Add the event listener to the target container (falling back to
   // the target if we didn't find one).
   listenToTopLevelEvent(
-    ((type: any): DOMTopLevelEventType),
+    type,
     rootContainerInstance,
     listenerMap,
     passive,

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

@@ -7,6 +7,7 @@
  * @flow
  */
 
+import type {DOMTopLevelEventType} from 'legacy-events/TopLevelEventTypes';
 import type {EventPriority} from 'shared/ReactTypes';
 import type {
   ReactDOMListenerEvent,
@@ -41,13 +42,13 @@ function resolveDispatcher() {
 }
 
 export function useEvent(
-  type: string,
+  type: DOMTopLevelEventType,
   options?: EventOptions,
 ): ReactDOMListenerMap {
   const dispatcher = resolveDispatcher();
   let capture = false;
   let passive = undefined; // Undefined means to use the browser default
-  let priority = getEventPriorityForListenerSystem((type: any));
+  let priority;
 
   if (options != null) {
     const optionsCapture = options.capture;
@@ -64,6 +65,9 @@ export function useEvent(
       priority = optionsPriority;
     }
   }
+  if (priority === undefined) {
+    priority = getEventPriorityForListenerSystem(type);
+  }
   const event: ReactDOMListenerEvent = {
     capture,
     passive,

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

@@ -224,8 +224,10 @@ export function getEventPriorityForPluginSystem(
   return priority === undefined ? ContinuousEvent : priority;
 }
 
-export function getEventPriorityForListenerSystem(type: string): EventPriority {
-  const priority = eventPriorities.get(((type: any): TopLevelType));
+export function getEventPriorityForListenerSystem(
+  type: DOMTopLevelEventType,
+): EventPriority {
+  const priority = eventPriorities.get(type);
   if (priority !== undefined) {
     return priority;
   }

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

@@ -404,7 +404,7 @@ export function attachElementListener(listener: ReactDOMListener): void {
   // Add the event listener to the target container (falling back to
   // the target if we didn't find one).
   listenToTopLevelEvent(
-    ((type: any): DOMTopLevelEventType),
+    type,
     containerEventTarget,
     listenerMap,
     passive,

packages/shared/ReactDOMTypes.js

@@ -13,6 +13,7 @@ import type {
   ReactEventResponderInstance,
   EventPriority,
 } from 'shared/ReactTypes';
+import type {DOMTopLevelEventType} from 'legacy-events/TopLevelEventTypes';
 
 type AnyNativeEvent = Event | KeyboardEvent | MouseEvent | Touch;
 
@@ -80,7 +81,7 @@ export type ReactDOMListenerEvent = {|
   capture: boolean,
   passive: void | boolean,
   priority: EventPriority,
-  type: string,
+  type: DOMTopLevelEventType,
 |};
 
 export type ReactDOMListenerMap = {|