react · paradowstack · Aug 13, 2026
diff --git a/packages/react-native-codegen/src/generators/modules/GenerateModuleJavaSpec.js b/packages/react-native-codegen/src/generators/modules/GenerateModuleJavaSpec.js
@@ -25,11 +25,7 @@ import type {AliasResolver} from './Utils';
 const {unwrapNullable} = require('../../parsers/parsers-commons');
 const {wrapOptional} = require('../TypeUtils/Java');
 const {parseValidUnionType, toPascalCase} = require('../Utils');
-const {
-  createAliasResolver,
-  getModules,
-  throwIfUnsupportedPromiseArrayBuffer,
-} = require('./Utils');
+const {createAliasResolver, getModules} = require('./Utils');
 
 type FilesOutput = Map<string, string>;
 
@@ -590,11 +586,6 @@ module.exports = {
             method.typeAnnotation,
           );
 
-        throwIfUnsupportedPromiseArrayBuffer(
-          method.name,
-          methodTypeAnnotation.returnTypeAnnotation,
-        );
-
         // Handle return type
         const translatedReturnType = translateFunctionReturnTypeToJavaType(
           methodTypeAnnotation.returnTypeAnnotation,

diff --git a/packages/react-native-codegen/src/generators/modules/GenerateModuleJniCpp.js b/packages/react-native-codegen/src/generators/modules/GenerateModuleJniCpp.js
@@ -24,11 +24,7 @@ import type {AliasResolver} from './Utils';
 
 const {unwrapNullable} = require('../../parsers/parsers-commons');
 const {parseValidUnionType} = require('../Utils');
-const {
-  createAliasResolver,
-  getModules,
-  throwIfUnsupportedPromiseArrayBuffer,
-} = require('./Utils');
+const {createAliasResolver, getModules} = require('./Utils');
 
 type FilesOutput = Map<string, string>;
 
@@ -47,15 +43,20 @@ const HostFunctionTemplate = ({
   propertyName,
   jniSignature,
   jsReturnType,
+  promiseResolveSupportsArrayBuffer,
 }: Readonly<{
   hasteModuleName: string,
   propertyName: string,
   jniSignature: string,
   jsReturnType: JSReturnType,
+  promiseResolveSupportsArrayBuffer: boolean,
 }>) => {
+  const promiseResolveSupportsArrayBufferArg = `, ${
+    promiseResolveSupportsArrayBuffer ? 'true' : 'false'
+  }`;
   return `static facebook::jsi::Value __hostFunction_${hasteModuleName}SpecJSI_${propertyName}(facebook::jsi::Runtime& rt, TurboModule &turboModule, const facebook::jsi::Value* args, size_t count) {
   static jmethodID cachedMethodId = nullptr;
-  return static_cast<JavaTurboModule &>(turboModule).invokeJavaMethod(rt, ${jsReturnType}, "${propertyName}", "${jniSignature}", args, count, cachedMethodId);
+  return static_cast<JavaTurboModule &>(turboModule).invokeJavaMethod(rt, ${jsReturnType}, "${propertyName}", "${jniSignature}", args, count, cachedMethodId${promiseResolveSupportsArrayBufferArg});
 }`;
 };
 
@@ -406,6 +407,23 @@ function translateReturnTypeToJniType(
   }
 }
 
+function doesPromiseResolveSupportArrayBuffer(
+  nullableReturnTypeAnnotation: Nullable<NativeModuleReturnTypeAnnotation>,
+): boolean {
+  const [returnTypeAnnotation] =
+    unwrapNullable<NativeModuleReturnTypeAnnotation>(
+      nullableReturnTypeAnnotation,
+    );
+  if (returnTypeAnnotation.type !== 'PromiseTypeAnnotation') {
+    return false;
+  }
+
+  let elementType = returnTypeAnnotation.elementType;
+  [elementType] = unwrapNullable(elementType);
+
+  return elementType.type === 'ArrayBufferTypeAnnotation';
+}
+
 function translateMethodTypeToJniSignature(
   property: NativeModulePropertyShape,
   resolveAlias: AliasResolver,
@@ -453,8 +471,6 @@ function translateMethodForImplementation(
     unwrapNullable<NativeModuleFunctionTypeAnnotation>(property.typeAnnotation);
   const {returnTypeAnnotation} = propertyTypeAnnotation;
 
-  throwIfUnsupportedPromiseArrayBuffer(property.name, returnTypeAnnotation);
-
   if (
     property.name === 'getConstants' &&
     returnTypeAnnotation.type === 'ObjectTypeAnnotation' &&
@@ -468,6 +484,8 @@ function translateMethodForImplementation(
     propertyName: property.name,
     jniSignature: translateMethodTypeToJniSignature(property, resolveAlias),
     jsReturnType: translateReturnTypeToKind(returnTypeAnnotation, resolveAlias),
+    promiseResolveSupportsArrayBuffer:
+      doesPromiseResolveSupportArrayBuffer(returnTypeAnnotation),
   });
 }
 

diff --git a/packages/react-native-codegen/src/generators/modules/GenerateModuleObjCpp/serializeMethod.js b/packages/react-native-codegen/src/generators/modules/GenerateModuleObjCpp/serializeMethod.js
@@ -26,7 +26,6 @@ const {
 } = require('../../../parsers/parsers-commons');
 const {wrapOptional} = require('../../TypeUtils/Objective-C');
 const {capitalize, parseValidUnionType} = require('../../Utils');
-const {throwIfUnsupportedPromiseArrayBuffer} = require('../Utils');
 const {getNamespacedStructName} = require('./Utils');
 const invariant = require('invariant');
 
@@ -104,11 +103,6 @@ function serializeMethod(
     }
   });
 
-  throwIfUnsupportedPromiseArrayBuffer(
-    methodName,
-    propertyTypeAnnotation.returnTypeAnnotation,
-  );
-
   // Unwrap returnTypeAnnotation, so we check if the return type is Promise
   // TODO(T76719514): Disallow nullable PromiseTypeAnnotations
   const [returnTypeAnnotation] = unwrapNullable(

diff --git a/packages/react-native-codegen/src/generators/modules/Utils.js b/packages/react-native-codegen/src/generators/modules/Utils.js
@@ -13,7 +13,6 @@
 import type {
   NativeModuleAliasMap,
   NativeModuleObjectTypeAnnotation,
-  NativeModuleReturnTypeAnnotation,
   NativeModuleSchema,
   NativeModuleTypeAnnotation,
   Nullable,
@@ -78,50 +77,9 @@ function isArrayRecursiveMember(
   );
 }
 
-// Platform-native (Java/Kotlin and ObjC) TurboModules copy ArrayBuffer
-// arguments and return ArrayBuffers zero-copy from synchronous methods, but
-// `Promise<ArrayBuffer>` is not part of their contract.
-//
-// On Android it cannot work: the resolve path serializes through
-// folly::dynamic, which cannot carry raw bytes. On iOS the resolve path is a
-// direct ObjC->jsi conversion that would in fact produce an ArrayBuffer for an
-// NSMutableData, so the limitation there is not technical — the guard is
-// applied to ObjC as well to keep one cross-platform contract, so a spec that
-// compiles for iOS cannot fail to build for Android.
-//
-// Reject `Promise<ArrayBuffer>` at codegen time for both native platforms so
-// the unsupported case surfaces as a build error rather than a runtime failure
-// or a silent iOS/Android divergence.
-function throwIfUnsupportedPromiseArrayBuffer(
-  methodName: string,
-  nullableReturnTypeAnnotation: Nullable<NativeModuleReturnTypeAnnotation>,
-): void {
-  const [returnTypeAnnotation] =
-    unwrapNullable<NativeModuleReturnTypeAnnotation>(
-      nullableReturnTypeAnnotation,
-    );
-  if (returnTypeAnnotation.type !== 'PromiseTypeAnnotation') {
-    return;
-  }
-  let elementType = returnTypeAnnotation.elementType;
-  if (elementType.type === 'NullableTypeAnnotation') {
-    elementType = elementType.typeAnnotation;
-  }
-  if (elementType.type === 'ArrayBufferTypeAnnotation') {
-    throw new Error(
-      `Unsupported return type for method "${methodName}": Promise<ArrayBuffer> is not ` +
-        'supported for Android (Java/Kotlin) or iOS (ObjC) TurboModules. Use a C++ ' +
-        '(Cxx) TurboModule, return the ArrayBuffer from a synchronous method, or resolve ' +
-        'the Promise with a different type. ArrayBuffer is still supported as a method ' +
-        'argument and as a synchronous return value on all platforms.',
-    );
-  }
-}
-
 module.exports = {
   createAliasResolver,
   getModules,
   isDirectRecursiveMember,
   isArrayRecursiveMember,
-  throwIfUnsupportedPromiseArrayBuffer,
 };
diff --git a/packages/react-native-codegen/src/generators/modules/__test_fixtures__/fixtures.js b/packages/react-native-codegen/src/generators/modules/__test_fixtures__/fixtures.js
@@ -2661,25 +2661,6 @@ const ARRAY_BUFFER_NATIVE_MODULE: SchemaType = {
               ],
             },
           },
-        ],
-      },
-      moduleName: 'SampleTurboModule',
-    },
-  },
-};
-
-// Promise<ArrayBuffer> is only supported by C++ (Cxx) TurboModules (see
-// throwIfUnsupportedPromiseArrayBuffer), so this fixture is excluded on both
-// Android and iOS. It keeps C++ codegen coverage for the async-return case.
-const ARRAY_BUFFER_PROMISE_NATIVE_MODULE: SchemaType = {
-  modules: {
-    NativeSampleTurboModule: {
-      type: 'NativeModule',
-      aliasMap: {},
-      enumMap: {},
-      spec: {
-        eventEmitters: [],
-        methods: [
           {
             name: 'promiseArrayBuffer',
             optional: false,
@@ -2694,10 +2675,26 @@ const ARRAY_BUFFER_PROMISE_NATIVE_MODULE: SchemaType = {
               params: [],
             },
           },
+          {
+            name: 'promiseNullableArrayBuffer',
+            optional: false,
+            typeAnnotation: {
+              type: 'FunctionTypeAnnotation',
+              returnTypeAnnotation: {
+                type: 'PromiseTypeAnnotation',
+                elementType: {
+                  type: 'NullableTypeAnnotation',
+                  typeAnnotation: {
+                    type: 'ArrayBufferTypeAnnotation',
+                  },
+                },
+              },
+              params: [],
+            },
+          },
         ],
       },
       moduleName: 'SampleTurboModule',
-      excludedPlatforms: ['android', 'iOS'],
     },
   },
 };
@@ -2896,7 +2893,6 @@ const STRING_LITERALS: SchemaType = {
 
 module.exports = {
   array_buffer_native_module: ARRAY_BUFFER_NATIVE_MODULE,
-  array_buffer_promise_native_module: ARRAY_BUFFER_PROMISE_NATIVE_MODULE,
   complex_objects: COMPLEX_OBJECTS,
   two_modules_different_files: TWO_MODULES_DIFFERENT_FILES,
   empty_native_modules: EMPTY_NATIVE_MODULES,

diff --git a/packages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleHObjCpp-test.js b/packages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleHObjCpp-test.js
@@ -10,8 +10,6 @@
 
 'use strict';
 
-import type {SchemaType} from '../../../CodegenSchema';
-
 const fixtures = require('../__test_fixtures__/fixtures.js');
 const generator = require('../GenerateModuleObjCpp');
 
@@ -33,42 +31,4 @@ describe('GenerateModuleHObjCpp', () => {
         ).toMatchSnapshot();
       });
     });
-
-  it('throws for a method returning Promise<ArrayBuffer> (unsupported on iOS)', () => {
-    const schema: SchemaType = {
-      modules: {
-        NativeSampleTurboModule: {
-          type: 'NativeModule',
-          aliasMap: {},
-          enumMap: {},
-          spec: {
-            eventEmitters: [],
-            methods: [
-              {
-                name: 'getAsyncBuffer',
-                optional: false,
-                typeAnnotation: {
-                  type: 'FunctionTypeAnnotation',
-                  returnTypeAnnotation: {
-                    type: 'PromiseTypeAnnotation',
-                    elementType: {type: 'ArrayBufferTypeAnnotation'},
-                  },
-                  params: [],
-                },
-              },
-            ],
-          },
-          moduleName: 'SampleTurboModule',
-        },
-      },
-    };
-    expect(() =>
-      generator.generate(
-        'array_buffer_promise_throws',
-        schema,
-        'com.facebook.fbreact.specs',
-        false,
-      ),
-    ).toThrow(/Promise<ArrayBuffer> is not supported/);
-  });
 });
diff --git a/...ages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleJavaSpec-test.js b/...ages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleJavaSpec-test.js
@@ -10,8 +10,6 @@
 
 'use strict';
 
-import type {SchemaType} from '../../../CodegenSchema';
-
 const fixtures = require('../__test_fixtures__/fixtures.js');
 const generator = require('../GenerateModuleJavaSpec.js');
 
@@ -31,37 +29,4 @@ describe('GenerateModuleJavaSpec', () => {
         ).toMatchSnapshot();
       });
     });
-
-  it('throws for a method returning Promise<ArrayBuffer> (unsupported on Android)', () => {
-    const schema: SchemaType = {
-      modules: {
-        NativeSampleTurboModule: {
-          type: 'NativeModule',
-          aliasMap: {},
-          enumMap: {},
-          spec: {
-            eventEmitters: [],
-            methods: [
-              {
-                name: 'getAsyncBuffer',
-                optional: false,
-                typeAnnotation: {
-                  type: 'FunctionTypeAnnotation',
-                  returnTypeAnnotation: {
-                    type: 'PromiseTypeAnnotation',
-                    elementType: {type: 'ArrayBufferTypeAnnotation'},
-                  },
-                  params: [],
-                },
-              },
-            ],
-          },
-          moduleName: 'SampleTurboModule',
-        },
-      },
-    };
-    expect(() =>
-      generator.generate('array_buffer_promise_throws', schema),
-    ).toThrow(/Promise<ArrayBuffer> is not supported/);
-  });
 });
diff --git a/packages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleJniCpp-test.js b/packages/react-native-codegen/src/generators/modules/__tests__/GenerateModuleJniCpp-test.js
@@ -10,8 +10,6 @@
 
 'use strict';
 
-import type {SchemaType} from '../../../CodegenSchema';
-
 const fixtures = require('../__test_fixtures__/fixtures.js');
 const generator = require('../GenerateModuleJniCpp.js');
 
@@ -31,41 +29,4 @@ describe('GenerateModuleJniCpp', () => {
         ).toMatchSnapshot();
       });
     });
-
-  it('throws for a method returning Promise<ArrayBuffer> (unsupported on Android)', () => {
-    const schema: SchemaType = {
-      modules: {
-        NativeSampleTurboModule: {
-          type: 'NativeModule',
-          aliasMap: {},
-          enumMap: {},
-          spec: {
-            eventEmitters: [],
-            methods: [
-              {
-                name: 'getAsyncBuffer',
-                optional: false,
-                typeAnnotation: {
-                  type: 'FunctionTypeAnnotation',
-                  returnTypeAnnotation: {
-                    type: 'PromiseTypeAnnotation',
-                    elementType: {type: 'ArrayBufferTypeAnnotation'},
-                  },
-                  params: [],
-                },
-              },
-            ],
-          },
-          moduleName: 'SampleTurboModule',
-        },
-      },
-    };
-    expect(() =>
-      generator.generate(
-        'array_buffer_promise_throws',
-        schema,
-        'com.facebook.fbreact.specs',
-      ),
-    ).toThrow(/Promise<ArrayBuffer> is not supported/);
-  });
 });