Add a post transform to rename the default export names (#50397)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/50397

Changelog: [Internal]

Reviewed By: huntie

Differential Revision: D72170157

fbshipit-source-id: 9067a83c5e941ef8ade7b846799d9a09f7dc4e62

packages/react-native/Libraries/Animated/nodes/AnimatedValue.js

@@ -10,7 +10,8 @@
 
 import type {EventSubscription} from '../../vendor/emitter/EventEmitter';
 import type {PlatformConfig} from '../AnimatedPlatformConfig';
-import type Animation, {EndCallback} from '../animations/Animation';
+import type Animation from '../animations/Animation';
+import type {EndCallback} from '../animations/Animation';
 import type {InterpolationConfigType} from './AnimatedInterpolation';
 import type AnimatedNode from './AnimatedNode';
 import type {AnimatedNodeConfig} from './AnimatedNode';

packages/virtualized-lists/Lists/VirtualizeUtils.js

@@ -10,9 +10,8 @@
 
 'use strict';
 
-import type ListMetricsAggregator, {
-  CellMetricProps,
-} from './ListMetricsAggregator';
+import type ListMetricsAggregator from './ListMetricsAggregator';
+import type {CellMetricProps} from './ListMetricsAggregator';
 
 import * as ReactNativeFeatureFlags from 'react-native/src/private/featureflags/ReactNativeFeatureFlags';
 

scripts/build/build-types/transforms/__tests__/replaceDefaultExportName-test.js

@@ -0,0 +1,42 @@
+/**
+ * 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
+ * @oncall react_native
+ */
+
+const createReplaceDefaultExportName = require('../replaceDefaultExportName.js');
+const babel = require('@babel/core');
+const flowApiTranslator = require('flow-api-translator');
+
+const prettierOptions = {parser: 'babel'};
+
+async function translate(code: string, fileName: string): Promise<string> {
+  const tsDef = await flowApiTranslator.translateFlowToTSDef(
+    code,
+    prettierOptions,
+  );
+  const result = await babel.transformAsync(tsDef, {
+    plugins: [
+      '@babel/plugin-syntax-typescript',
+      createReplaceDefaultExportName(fileName),
+    ],
+  });
+
+  return result.code;
+}
+
+describe('replaceDefaultExportName', () => {
+  test('should replace default export name with unambiguous one', async () => {
+    const code = `export default Foo;`;
+    const result = await translate(code, 'mock/path/to/module/Foo.js');
+    expect(result).toMatchInlineSnapshot(`
+      "declare const Foo_DEFAULT: typeof Foo;
+      export default Foo_DEFAULT;"
+    `);
+  });
+});

scripts/build/build-types/transforms/replaceDefaultExportName.js

@@ -0,0 +1,29 @@
+/**
+ * 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
+ * @oncall react_native
+ */
+
+import type {PluginObj} from '@babel/core';
+
+function createReplaceDefaultExportName(filePath: string): PluginObj<mixed> {
+  return {
+    visitor: {
+      Identifier(node) {
+        const fileName = filePath.split('/').pop() ?? '';
+        const moduleName = fileName.split('.')[0];
+
+        if (node.node.name === '$$EXPORT_DEFAULT_DECLARATION$$') {
+          node.node.name = `${moduleName}_DEFAULT`;
+        }
+      },
+    },
+  };
+}
+
+module.exports = createReplaceDefaultExportName;

scripts/build/build-types/translateSourceFile.js

@@ -14,6 +14,7 @@ import type {ParseResult} from 'hermes-transform/dist/transform/parse';
 import type {TransformASTResult} from 'hermes-transform/dist/transform/transformAST';
 
 const getDependencies = require('./resolution/getDependencies');
+const createReplaceDefaultExportName = require('./transforms/replaceDefaultExportName');
 const babel = require('@babel/core');
 const translate = require('flow-api-translator');
 const {parse, print} = require('hermes-transform');
@@ -77,7 +78,7 @@ async function translateSourceFile(
   }
 
   // Apply post-transforms
-  const result = await applyPostTransforms(tsDefResult);
+  const result = await applyPostTransforms(tsDefResult, filePath);
 
   return {
     result,
@@ -101,14 +102,16 @@ async function applyPreTransforms(source: ParseResult): Promise<ParseResult> {
 /**
  * Apply post-transforms to .d.ts source code containing @build-types directives.
  */
-async function applyPostTransforms(source: string): Promise<string> {
-  if (!source.includes('@build-types')) {
-    // Exiting early, as there are no @build-types directives
-    return source;
-  }
-
+async function applyPostTransforms(
+  source: string,
+  filePath: string,
+): Promise<string> {
   const result = await babel.transformAsync(source, {
-    plugins: ['@babel/plugin-syntax-typescript', ...postTransforms],
+    plugins: [
+      '@babel/plugin-syntax-typescript',
+      ...postTransforms,
+      createReplaceDefaultExportName(filePath),
+    ],
   });
 
   return result.code;