improve options parser

Reviewed By: jeanlauliac

Differential Revision: D4146832

fbshipit-source-id: a54284ccc3fa4d6e1628886b748b21b9b9af2cff

packager/react-packager/src/ModuleGraph/worker.js

@@ -70,7 +70,7 @@ function transformJSON(infile, options, outfile, callback) {
 }
 
 function transformModule(infile, options, outfile, callback) {
-  const filename = options.filename || infile;
+  const filename = infile;
   if (filename.endsWith('.json')) {
     return transformJSON(infile, options, outfile, callback);
   }

packager/react-packager/src/ModuleGraph/worker.js.flow

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @flow
+ */
+'use strict';
+
+declare export function transformModule(
+  infile: string,
+  options: {
+    filename?: string,
+    transform: string,
+    variants?: {[key: string]: Object},
+  },
+  outfile: string,
+  callback: (e?: Error) => void,
+): void
+
+declare export function optimizeModule(
+  infile: string,
+  outfile: string,
+  options: {
+    dev?: boolean,
+    platform?: string,
+  },
+  callback: (e?: Error) => void,
+): void