Switch Platform Constansts to use typedConstants structs

Summary: It's actually the first module in OSS which is typed with taking advantages of codegen.

Reviewed By: RSNara

Differential Revision: D16620334

fbshipit-source-id: 65d6656506f2a4c68d493939ecfa65ba975abead

Author: osdnk

React/CoreModules/RCTPlatform.mm

@@ -50,23 +50,28 @@ - (dispatch_queue_t)methodQueue
 }
 
 // TODO: Use the generated struct return type.
-- (NSDictionary<NSString *, id> *)constantsToExport
+- (ModuleConstants<JS::NativePlatformConstantsIOS::Constants>)constantsToExport
 {
-  return [self getConstants];
+  return (ModuleConstants<JS::NativePlatformConstantsIOS::Constants>)[self getConstants];
 }
 
-// TODO: Use the generated struct return type.
-- (NSDictionary<NSString *, id> *)getConstants
+- (ModuleConstants<JS::NativePlatformConstantsIOS::Constants>)getConstants
 {
   UIDevice *device = [UIDevice currentDevice];
-  return @{
-    @"forceTouchAvailable": @(RCTForceTouchAvailable()),
-    @"osVersion": [device systemVersion],
-    @"systemName": [device systemName],
-    @"interfaceIdiom": interfaceIdiom([device userInterfaceIdiom]),
-    @"isTesting": @(RCTRunningInTestEnvironment()),
-    @"reactNativeVersion": RCTGetReactNativeVersion(),
-  };
+  auto versions = RCTGetReactNativeVersion();
+  return typedConstants<JS::NativePlatformConstantsIOS::Constants>({
+    .forceTouchAvailable = @(RCTForceTouchAvailable()),
+    .osVersion = [device systemVersion],
+    .systemName = [device systemName],
+    .interfaceIdiom = interfaceIdiom([device userInterfaceIdiom]),
+    .isTesting = @(RCTRunningInTestEnvironment()),
+    .reactNativeVersion = JS::NativePlatformConstantsIOS::ConstantsReactNativeVersion::Builder({
+      .minor = [versions[@"minor"] doubleValue],
+      .major = [versions[@"major"] doubleValue],
+      .patch = [versions[@"patch"] doubleValue],
+      .prerelease = [versions[@"prerelease"] isKindOfClass: [NSNull class]] ? folly::Optional<double>{} : [versions[@"prerelease"] doubleValue]
+    }),
+  });
 }
 
 - (std::shared_ptr<TurboModule>)getTurboModuleWithJsInvoker:(std::shared_ptr<JSCallInvoker>)jsInvoker