Use type aliases for native module getConstants where applicable

Summary:
## Changelog:
[Internal] -

This replaces object literal return types in `getConstants()` for core RN native modules with type aliases.

This is a valid change from the point of view of binary compatibility between native/JS, and provides a couple of benefits, such as clearer code in general, but also ability to employ C++ codegen for the corresponding types and their marshalling.

bypass-github-export-checks

Reviewed By: christophpurrer

Differential Revision: D48685992

fbshipit-source-id: f21358b12448d30a7b5e25e81f62ef77964d1fcd

packages/react-native/Libraries/AppState/NativeAppState.js

@@ -12,10 +12,12 @@ import type {TurboModule} from '../TurboModule/RCTExport';
 
 import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
 
+export type AppStateConstants = {|
+  initialAppState: string,
+|};
+
 export interface Spec extends TurboModule {
-  +getConstants: () => {|
-    initialAppState: string,
-  |};
+  +getConstants: () => AppStateConstants;
   +getCurrentAppState: (
     success: (appState: {|app_state: string|}) => void,
     error: (error: Object) => void,

packages/react-native/Libraries/ReactNative/I18nManager.js

@@ -8,15 +8,13 @@
  * @format
  */
 
+import type {I18nManagerConstants} from './NativeI18nManager';
+
 import NativeI18nManager from './NativeI18nManager';
 
-const i18nConstants: {|
-  doLeftAndRightSwapInRTL: boolean,
-  isRTL: boolean,
-  localeIdentifier?: ?string,
-|} = getI18nManagerConstants();
+const i18nConstants: I18nManagerConstants = getI18nManagerConstants();
 
-function getI18nManagerConstants() {
+function getI18nManagerConstants(): I18nManagerConstants {
   if (NativeI18nManager) {
     const {isRTL, doLeftAndRightSwapInRTL, localeIdentifier} =
       NativeI18nManager.getConstants();
@@ -30,11 +28,7 @@ function getI18nManagerConstants() {
 }
 
 module.exports = {
-  getConstants: (): {|
-    doLeftAndRightSwapInRTL: boolean,
-    isRTL: boolean,
-    localeIdentifier: ?string,
-  |} => {
+  getConstants: (): I18nManagerConstants => {
     return i18nConstants;
   },
 

packages/react-native/Libraries/ReactNative/NativeI18nManager.js

@@ -12,12 +12,14 @@ import type {TurboModule} from '../TurboModule/RCTExport';
 
 import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
 
+export type I18nManagerConstants = {|
+  doLeftAndRightSwapInRTL: boolean,
+  isRTL: boolean,
+  localeIdentifier?: ?string,
+|};
+
 export interface Spec extends TurboModule {
-  +getConstants: () => {|
-    isRTL: boolean,
-    doLeftAndRightSwapInRTL: boolean,
-    localeIdentifier: ?string,
-  |};
+  +getConstants: () => I18nManagerConstants;
   allowRTL: (allowRTL: boolean) => void;
   forceRTL: (forceRTL: boolean) => void;
   swapLeftAndRightInRTL: (flipStyles: boolean) => void;

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

@@ -40,10 +40,7 @@ export type DeviceInfoConstants = {|
 |};
 
 export interface Spec extends TurboModule {
-  +getConstants: () => {|
-    +Dimensions: DimensionsPayload,
-    +isIPhoneX_deprecated?: boolean,
-  |};
+  +getConstants: () => DeviceInfoConstants;
 }
 
 const NativeModule: Spec = TurboModuleRegistry.getEnforcing<Spec>('DeviceInfo');

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

@@ -12,26 +12,30 @@ import type {TurboModule} from '../TurboModule/RCTExport';
 
 import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
 
+export type ReactNativeVersionAndroid = {|
+  major: number,
+  minor: number,
+  patch: number,
+  prerelease: ?number,
+|};
+
+export type PlatformConstantsAndroid = {|
+  isTesting: boolean,
+  isDisableAnimations?: boolean,
+  reactNativeVersion: ReactNativeVersionAndroid,
+  Version: number,
+  Release: string,
+  Serial: string,
+  Fingerprint: string,
+  Model: string,
+  ServerHost?: string,
+  uiMode: string,
+  Brand: string,
+  Manufacturer: string,
+|};
+
 export interface Spec extends TurboModule {
-  +getConstants: () => {|
-    isTesting: boolean,
-    isDisableAnimations?: boolean,
-    reactNativeVersion: {|
-      major: number,
-      minor: number,
-      patch: number,
-      prerelease: ?number,
-    |},
-    Version: number,
-    Release: string,
-    Serial: string,
-    Fingerprint: string,
-    Model: string,
-    ServerHost?: string,
-    uiMode: string,
-    Brand: string,
-    Manufacturer: string,
-  |};
+  +getConstants: () => PlatformConstantsAndroid;
   +getAndroidID: () => string;
 }
 

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

@@ -12,21 +12,23 @@ import type {TurboModule} from '../TurboModule/RCTExport';
 
 import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
 
+export type PlatformConstantsIOS = {|
+  isTesting: boolean,
+  isDisableAnimations?: boolean,
+  reactNativeVersion: {|
+    major: number,
+    minor: number,
+    patch: number,
+    prerelease: ?number,
+  |},
+  forceTouchAvailable: boolean,
+  osVersion: string,
+  systemName: string,
+  interfaceIdiom: string,
+|};
+
 export interface Spec extends TurboModule {
-  +getConstants: () => {|
-    isTesting: boolean,
-    isDisableAnimations?: boolean,
-    reactNativeVersion: {|
-      major: number,
-      minor: number,
-      patch: number,
-      prerelease: ?number,
-    |},
-    forceTouchAvailable: boolean,
-    osVersion: string,
-    systemName: string,
-    interfaceIdiom: string,
-  |};
+  +getConstants: () => PlatformConstantsIOS;
 }
 
 export default (TurboModuleRegistry.getEnforcing<Spec>(