Metro windows path resolution

packages/metro-core/project.json

@@ -27,6 +27,14 @@
       "options": {
         "lintFilePatterns": ["packages/metro-core/**/*.{ts,tsx,js,jsx}"]
       }
+    },
+    "test": {
+      "executor": "@nx/jest:jest",
+      "outputs": ["{workspaceRoot}/coverage/packages/metro-core"],
+      "options": {
+        "jestConfig": "packages/metro-core/jest.config.ts",
+        "passWithNoTests": true
+      }
     }
   }
 }

packages/metro-core/src/babel/transformer.js

@@ -1,5 +1,5 @@
 /* eslint-disable no-undef */
-const babelTransformer = require('__BABEL_TRANSFORMER_PATH__');
+const babelTransformer = require(__BABEL_TRANSFORMER_PATH__);
 const babelPlugins = __BABEL_PLUGINS__;
 /* eslint-enable no-undef */
 

packages/metro-core/src/plugin/__tests__/babel-transformer.test.ts

@@ -0,0 +1,39 @@
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { createBabelTransformer } from '../babel-transformer';
+import type { ModuleFederationConfigNormalized } from '../../types';
+
+function createConfig(): ModuleFederationConfigNormalized {
+  return {
+    name: 'test-app',
+    filename: 'remote.js',
+    remotes: {},
+    exposes: {},
+    shared: {},
+    shareStrategy: 'loaded-first',
+    plugins: [],
+  };
+}
+
+describe('createBabelTransformer', () => {
+  it('escapes Windows paths for require()', () => {
+    const tmpDirPath = fs.mkdtempSync(path.join(os.tmpdir(), 'mf-metro-'));
+    const windowsPath =
+      'C:\\Users\\someone\\project\\node_modules\\metro-babel-transformer\\src\\index.js';
+
+    const outputPath = createBabelTransformer({
+      blacklistedPaths: [],
+      federationConfig: createConfig(),
+      originalBabelTransformerPath: windowsPath,
+      tmpDirPath,
+      enableInitializeCorePatching: false,
+      enableRuntimeRequirePatching: false,
+    });
+
+    const output = fs.readFileSync(outputPath, 'utf-8');
+    expect(output).toContain(`require(${JSON.stringify(windowsPath)})`);
+
+    fs.rmSync(tmpDirPath, { recursive: true, force: true });
+  });
+});

packages/metro-core/src/plugin/babel-transformer.ts

@@ -41,7 +41,10 @@ export function createBabelTransformer({
   ].filter(Boolean);
 
   const babelTransformer = transformerTemplate
-    .replaceAll('__BABEL_TRANSFORMER_PATH__', originalBabelTransformerPath)
+    .replaceAll(
+      '__BABEL_TRANSFORMER_PATH__',
+      JSON.stringify(originalBabelTransformerPath),
+    )
     .replaceAll('__BABEL_PLUGINS__', JSON.stringify(plugins));
 
   fs.writeFileSync(outputPath, babelTransformer, 'utf-8');