Add LegacyObject to keep Flow Object as Object in the TypeScript API

packages/react-native-codegen/src/parsers/__tests__/parsers-primitives-test.js

@@ -1902,6 +1902,26 @@ describe('emitUnion', () => {
       });
     });
 
+    describe("when 'typeAnnotation.id.name' is 'LegacyObject'", () => {
+      const typeAnnotation = {
+        typeParameters: {
+          params: [1, 2],
+          type: 'GenericObjectTypeAnnotation',
+        },
+        id: {
+          name: 'LegacyObject',
+        },
+      };
+      const expected = {
+        type: 'GenericObjectTypeAnnotation',
+      };
+      const result = emitCommonTypesForUnitTest(typeAnnotation, false);
+
+      it("returns 'GenericObjectTypeAnnotation'", () => {
+        expect(result).toEqual(expected);
+      });
+    });
+
     describe("when 'typeAnnotation.id.name' is 'Object'", () => {
       const typeAnnotation = {
         typeParameters: {

packages/react-native-codegen/src/parsers/parsers-primitives.js

@@ -667,6 +667,7 @@ function emitCommonTypes(
     Double: emitDouble,
     Float: emitFloat,
     UnsafeObject: emitGenericObject,
+    LegacyObject: emitGenericObject,
     Object: emitGenericObject,
     $Partial: emitPartial,
     Partial: emitPartial,

packages/react-native-codegen/src/parsers/utils.js

@@ -34,10 +34,10 @@ function extractNativeModuleName(filename: string): string {
 export type ParserErrorCapturer = <T>(fn: () => T) => ?T;
 
 // $FlowFixMe[unclear-type] there's no flowtype for ASTs
-export type PropAST = Object;
+export type PropAST = any;
 
 // $FlowFixMe[unclear-type] there's no flowtype for ASTs
-export type ASTNode = Object;
+export type ASTNode = any;
 
 function createParserErrorCapturer(): [
   Array<ParserError>,

packages/react-native/Libraries/EventEmitter/NativeEventEmitter.js

@@ -45,8 +45,7 @@ export type {EventSubscription, EmitterSubscription};
 /** @deprecated Use `EventSubscription` instead. */
 export type NativeEventSubscription = EventSubscription;
 
-// $FlowFixMe[unclear-type] unclear type of events
-type UnsafeNativeEventObject = Object;
+type UnsafeNativeEventObject = LegacyObject;
 
 /**
  * `NativeEventEmitter` is intended for use by Native Modules to emit events to

packages/react-native/Libraries/PushNotificationIOS/PushNotificationIOS.js

@@ -123,8 +123,7 @@ export interface PushNotification {
   /**
    * An alias for `getAlert` to get the notification's main message string
    */
-  // $FlowFixMe[unclear-type]
-  getMessage(): ?string | ?Object;
+  getMessage(): ?string | ?LegacyObject;
 
   /**
    * Gets the sound string from the `aps` object
@@ -139,8 +138,7 @@ export interface PushNotification {
   /**
    * Gets the notification's main message from the `aps` object
    */
-  // $FlowFixMe[unclear-type]
-  getAlert(): ?string | ?Object;
+  getAlert(): ?string | ?LegacyObject;
 
   /**
    * Gets the content-available number from the `aps` object
@@ -155,8 +153,7 @@ export interface PushNotification {
   /**
    * Gets the data object on the notif
    */
-  // $FlowFixMe[unclear-type]
-  getData(): ?Object;
+  getData(): ?LegacyObject;
 
   /**
    * Gets the thread ID on the notif
@@ -550,8 +547,7 @@ class PushNotificationIOS {
    * `getInitialNotification` is sufficient.
    *
    */
-  // $FlowFixMe[unclear-type]
-  constructor(nativeNotif: Object) {
+  constructor(nativeNotif: LegacyObject) {
     this._data = {};
     this._remoteNotificationCompleteCallbackCalled = false;
     this._isRemote = nativeNotif.remote;
@@ -615,8 +611,7 @@ class PushNotificationIOS {
   /**
    * An alias for `getAlert` to get the notification's main message string.
    */
-  // $FlowFixMe[unclear-type]
-  getMessage(): ?string | ?Object {
+  getMessage(): ?string | ?LegacyObject {
     // alias because "alert" is an ambiguous name
     return this._alert;
   }
@@ -646,8 +641,7 @@ class PushNotificationIOS {
    *
    * See https://reactnative.dev/docs/pushnotificationios#getalert
    */
-  // $FlowFixMe[unclear-type]
-  getAlert(): ?string | ?Object {
+  getAlert(): ?string | ?LegacyObject {
     return this._alert;
   }
 
@@ -674,8 +668,7 @@ class PushNotificationIOS {
    *
    * See https://reactnative.dev/docs/pushnotificationios#getdata
    */
-  // $FlowFixMe[unclear-type]
-  getData(): ?Object {
+  getData(): ?LegacyObject {
     return this._data;
   }
 

packages/react-native/Libraries/Types/CodegenTypes.js

@@ -29,8 +29,7 @@ export type DirectEventHandler<
 export type Double = number;
 export type Float = number;
 export type Int32 = number;
-/* $FlowFixMe[unclear-type] Object is forbidden in strict mode */
-export type UnsafeObject = Object;
+export type UnsafeObject = LegacyObject;
 export type UnsafeMixed = unknown;
 
 type DefaultTypes = number | boolean | string | ReadonlyArray<string>;

packages/react-native/Libraries/vendor/emitter/EventEmitter.js

@@ -8,8 +8,7 @@
  * @format
  */
 
-// $FlowFixMe[unclear-type] unclear type of events
-type UnsafeEventObject = Object;
+type UnsafeEventObject = LegacyObject;
 
 export interface EventSubscription {
   remove(): void;
@@ -78,8 +77,7 @@ export default class EventEmitter<
   TEventToArgsMap extends Readonly<
     Record<string, ReadonlyArray<UnsafeEventObject>>,
   > = Readonly<Record<string, ReadonlyArray<UnsafeEventObject>>>,
-> implements IEventEmitter<TEventToArgsMap>
-{
+> implements IEventEmitter<TEventToArgsMap> {
   #registry: Registry<TEventToArgsMap>;
 
   constructor() {

packages/react-native/flow/LegacyObject.js

@@ -0,0 +1,13 @@
+/**
+ * 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
+ * @format
+ */
+
+// The legacy Flow `Object` type, which is `any`. The generated TypeScript API
+// (scripts/js-api/build-types) translates this type to `Object`.
+declare type LegacyObject = any;

packages/react-native/src/private/specs_DEPRECATED/modules/NativeExceptionsManager.js

@@ -29,8 +29,7 @@ export type ExceptionData = {
   stack: Array<StackFrame>,
   id: number,
   isFatal: boolean,
-  // flowlint-next-line unclear-type:off
-  extraData?: Object,
+  extraData?: LegacyObject,
   ...
 };
 export interface Spec extends TurboModule {

packages/react-native/src/private/specs_DEPRECATED/modules/NativeSegmentFetcher.js

@@ -15,13 +15,13 @@ import * as TurboModuleRegistry from '../../../../Libraries/TurboModule/TurboMod
 export interface Spec extends TurboModule {
   readonly fetchSegment: (
     segmentId: number,
-    options: Object, // flowlint-line unclear-type: off
-    callback: (error: ?Object) => void, // flowlint-line unclear-type: off
+    options: LegacyObject,
+    callback: (error: ?LegacyObject) => void,
   ) => void;
   readonly getSegment?: (
     segmentId: number,
-    options: Object, // flowlint-line unclear-type: off
-    callback: (error: ?Object, path: ?string) => void, // flowlint-line unclear-type: off
+    options: LegacyObject,
+    callback: (error: ?LegacyObject, path: ?string) => void,
   ) => void;
 }
 

scripts/js-api/build-types/transforms/flow/__tests__/replaceLegacyObjectWithObject-test.js

@@ -0,0 +1,49 @@
+/**
+ * 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
+ */
+
+const replaceLegacyObjectWithObject = require('../replaceLegacyObjectWithObject');
+const {parse, print} = require('flow-transform');
+
+const prettierOptions = {parser: 'babel'};
+
+async function translate(code: string): Promise<string> {
+  const parsed = await parse(code);
+  const result = await replaceLegacyObjectWithObject(parsed);
+  return print(result.ast, result.mutatedCode, prettierOptions);
+}
+
+describe('replaceLegacyObjectWithObject', () => {
+  test('should replace LegacyObject with Object in return annotation', async () => {
+    const code = `function foo(): LegacyObject {}`;
+    const result = await translate(code);
+    expect(result).toMatchInlineSnapshot(`
+      "function foo(): Object {}
+      "
+    `);
+  });
+
+  test('should replace LegacyObject with Object in nullable union', async () => {
+    const code = `let foo: ?string | ?LegacyObject;`;
+    const result = await translate(code);
+    expect(result).toMatchInlineSnapshot(`
+      "let foo: ?string | ?Object;
+      "
+    `);
+  });
+
+  test('should replace LegacyObject with Object in type alias', async () => {
+    const code = `type Foo = LegacyObject;`;
+    const result = await translate(code);
+    expect(result).toMatchInlineSnapshot(`
+      "type Foo = Object;
+      "
+    `);
+  });
+});

scripts/js-api/build-types/transforms/flow/replaceLegacyObjectWithObject.js

@@ -0,0 +1,43 @@
+/**
+ * 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 {TransformVisitor} from 'flow-transform';
+import type {ParseResult} from 'flow-transform/dist/transform/parse';
+import type {TransformASTResult} from 'flow-transform/dist/transform/transformAST';
+
+const {transformAST} = require('flow-transform/dist/transform/transformAST');
+
+const visitors: TransformVisitor = context => ({
+  GenericTypeAnnotation(node): void {
+    if (node.id.name === 'LegacyObject') {
+      // $FlowExpectedError[incompatible-type] - replaceNode doesn't accept a GenericTypeAnnotation object literal
+      context.replaceNode(node, {
+        type: 'GenericTypeAnnotation',
+        id: {
+          type: 'Identifier',
+          name: 'Object',
+          optional: false,
+        },
+      });
+    }
+  },
+});
+
+/**
+ * Replaces all LegacyObject type references with Object. LegacyObject is
+ * `any` in Flow, but should keep the `Object` type in the TypeScript API.
+ */
+async function replaceLegacyObjectWithObject(
+  source: ParseResult,
+): Promise<TransformASTResult> {
+  return transformAST(source, visitors);
+}
+
+module.exports = replaceLegacyObjectWithObject;

scripts/js-api/build-types/translateSourceFile.js

@@ -24,6 +24,7 @@ const preTransforms: Array<PreTransformFn> = [
   require('./transforms/flow/replaceRequiresWithImports'),
   require('./transforms/flow/replaceEmptyWithNever'),
   require('./transforms/flow/replaceStringishWithString'),
+  require('./transforms/flow/replaceLegacyObjectWithObject'),
   require('./transforms/flow/replaceNullablePropertiesWithUndefined'),
   require('./transforms/flow/reattachDocComments'),
   require('./transforms/flow/ensureNoUnprefixedProps'),