Special case plain CJS requires and conditional imports using __esModule

This models if the server tries to import .default or a plain require.
We should replicate the same thing on the client when we load that
module reference.

fixtures/flight/server/handler.server.js

@@ -36,6 +36,16 @@ module.exports = async function(req, res) {
         chunks: ['3'],
         name: 'default',
       },
+      '': {
+        id: './src/ShowMore.client.js',
+        chunks: ['3'],
+        name: '',
+      },
+      '*': {
+        id: './src/ShowMore.client.js',
+        chunks: ['3'],
+        name: '*',
+      },
     },
   });
 };

packages/react-transport-dom-webpack/src/ReactFlightClientWebpackBundlerConfig.js

@@ -59,5 +59,16 @@ export function requireModule<T>(moduleData: ModuleReference<T>): T {
       throw entry;
     }
   }
-  return __webpack_require__(moduleData.id)[moduleData.name];
+  const moduleExports = __webpack_require__(moduleData.id);
+  if (moduleData.name === '*') {
+    // This is a placeholder value that represents that the caller imported this
+    // as a CommonJS module as is.
+    return moduleExports;
+  }
+  if (moduleData.name === '') {
+    // This is a placeholder value that represents that the caller accessed the
+    // default property of this if it was an ESM interop module.
+    return moduleExports.__esModule ? moduleExports.default : moduleExports;
+  }
+  return moduleExports[moduleData.name];
 }

scripts/flow/environment.js

@@ -68,4 +68,4 @@ declare module 'EventListener' {
 }
 
 declare function __webpack_chunk_load__(id: string): Promise<mixed>;
-declare function __webpack_require__(id: string): {default: any};
+declare function __webpack_require__(id: string): any;