Add annotations to fix future natural inference errors in xplat/js: 4/n (#53469)

Summary:
Pull Request resolved: #53469

Changelog: [Internal]

Reviewed By: marcoww6

Differential Revision: D81067843

fbshipit-source-id: f75116da9be89d35c5befb4c90272ecc67d52caf

Author: SamChou19815

packages/dev-middleware/src/inspector-proxy/Device.js

@@ -970,7 +970,10 @@ export default class Device {
     socket: WS,
   ): void {
     const sendSuccessResponse = (scriptSource: string) => {
-      const result = {scriptSource};
+      const result: {
+        scriptSource: string,
+        bytecode?: string,
+      } = {scriptSource};
       const response: CDPResponse<'Debugger.getScriptSource'> = {
         id: req.id,
         result,

packages/react-native/Libraries/Utilities/SceneTracker.js

@@ -14,7 +14,7 @@ export type Scene = {name: string, [string]: mixed, ...};
 
 let _listeners: Array<(scene: Scene) => void> = [];
 
-let _activeScene = {name: 'default'};
+let _activeScene: Scene = {name: 'default'};
 
 const SceneTracker = {
   setActiveScene(scene: Scene) {

packages/react-native/src/private/webapis/dom/nodes/__tests__/ReactNativeElement-traversal-benchmark-itest.js

@@ -11,6 +11,7 @@
 import '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
 
 import type {HostInstance} from 'react-native';
+import type {FnOptions} from 'tinybench';
 
 import ensureInstance from '../../../../__tests__/utilities/ensureInstance';
 import ReactNativeElement from '../ReactNativeElement';
@@ -21,7 +22,7 @@ import {View} from 'react-native';
 let root;
 let node;
 
-const commonOptions = {
+const commonOptions: FnOptions = {
   beforeAll: () => {
     root = Fantom.createRoot();