react-native code-gen > Add a C++ only TurboModule example (for Android/iOS/macOS/Windows) (#35138)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35138

Changelog:

[General][Added] - Add a C++ only TurboModule example (for Android/iOS/macOS/Windows)

react-native@0.69 introduced a new bridging layer to ease integration for pure C++ TurboModules using C++ std:: types directly instead of the lower level jsi:: types:
https://github.com/facebook/react-native/tree/v0.69.0/ReactCommon/react/bridging

This bridging layer can be used in JSI functions or more conveniently in C++ TurboModules.

Here is a example of an C++ only TurboModule which will work on Android and iOS and macOS/Windows (using microsoft/react-native-macos|windows) only using flow/TypeScript and standard C++ types.

C++ only TurboModules are very handy as they do not require to work with JSI APIs - instead std:: or custom C++ can by used.

Reviewed By: javache

Differential Revision: D39011736

fbshipit-source-id: 84c833d8540671fde8505f1aeb0265074b248730

packages/rn-tester/NativeCxxModuleExample/NativeCxxModuleExample.js

@@ -0,0 +1,64 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+import type {TurboModule} from 'react-native/Libraries/TurboModule/RCTExport';
+
+import {TurboModuleRegistry} from 'react-native';
+
+/** FIXME: Enable flow-enum support
+export enum EnumInt {
+  A = 23,
+  B = 42,
+}
+*/
+
+export type UnionFloat = 1.44 | 2.88 | 5.76;
+export type UnionString = 'One' | 'Two' | 'Three';
+export type UnionObject = {value: number} | {low: string};
+
+export type ConstantsStruct = {|
+  const1: boolean,
+  const2: number,
+  const3: string,
+|};
+
+export type ObjectStruct = {|
+  a: number,
+  b: string,
+  c?: ?string,
+|};
+
+export type ValueStruct = {|
+  x: number,
+  y: string,
+  z: ObjectStruct,
+|};
+
+export interface Spec extends TurboModule {
+  +getArray: (arg: Array<ObjectStruct | null>) => Array<ObjectStruct | null>;
+  +getBool: (arg: boolean) => boolean;
+  +getConstants: () => ConstantsStruct;
+  // FIXME: Enable flow-enum support
+  +getEnum: (arg: number /*EnumInt*/) => number /*EnumInt*/;
+  +getMap: (arg: {[key: string]: ?number}) => {[key: string]: ?number};
+  +getNumber: (arg: number) => number;
+  +getObject: (arg: ObjectStruct) => ObjectStruct;
+  +getSet: (arg: Array<number>) => Array<number>;
+  +getString: (arg: string) => string;
+  +getUnion: (x: UnionFloat, y: UnionString, z: UnionObject) => string;
+  +getValue: (x: number, y: string, z: ObjectStruct) => ValueStruct;
+  +getValueWithCallback: (callback: (value: string) => void) => void;
+  +getValueWithPromise: (error: boolean) => Promise<string>;
+  +voidFunc: () => void;
+}
+
+export default (TurboModuleRegistry.get<Spec>(
+  'NativeCxxModuleExampleCxx',
+): ?Spec);