From df9fa32b8281f84f349f8438b0ec756e035f9f57 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Tue, 13 Jan 2015 01:12:14 +1100
Subject: [PATCH] add optional to keep module id extensions - fixes #420

---
 bin/6to5/index.js                           | 28 +++++++++--------
 lib/6to5/file.js                            | 33 +++++++++++----------
 lib/6to5/transformation/modules/_default.js |  6 ++--
 3 files changed, 36 insertions(+), 31 deletions(-)

diff --git a/bin/6to5/index.js b/bin/6to5/index.js
index 09d7925e43..ea5cc727d5 100755
--- a/bin/6to5/index.js
+++ b/bin/6to5/index.js
@@ -26,6 +26,7 @@ commander.option("-a, --amd-module-ids", "Insert module id in AMD modules", fals
 commander.option("-m, --module-ids", "Insert module id in modules", false);
 commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
 commander.option("-E, --include-regenerator", "Include the regenerator runtime if necessary", false);
+commander.option("--keep-module-id-extensions", "Keep extensions when generating module ids", false);
 
 commander.on("--help", function(){
   var outKeys = function (title, obj) {
@@ -101,19 +102,20 @@ if (errors.length) {
 //
 
 exports.opts = {
-  includeRegenerator: commander.includeRegenerator,
-  sourceMapName:      commander.outFile,
-  experimental:       commander.experimental,
-  reactCompat:        commander.reactCompat,
-  playground:         commander.playground,
-  moduleIds:          commander.amdModuleIds || commander.moduleIds,
-  blacklist:          commander.blacklist,
-  whitelist:          commander.whitelist,
-  sourceMap:          commander.sourceMaps || commander.sourceMapsInline,
-  optional:           commander.optional,
-  comments:           !commander.removeComments,
-  runtime:            commander.runtime,
-  modules:            commander.modules,
+  keepModuleIdExtensions: commander.keepModuleIdExtensions,
+  includeRegenerator:     commander.includeRegenerator,
+  sourceMapName:          commander.outFile,
+  experimental:           commander.experimental,
+  reactCompat:            commander.reactCompat,
+  playground:             commander.playground,
+  moduleIds:              commander.amdModuleIds || commander.moduleIds,
+  blacklist:              commander.blacklist,
+  whitelist:              commander.whitelist,
+  sourceMap:              commander.sourceMaps || commander.sourceMapsInline,
+  optional:               commander.optional,
+  comments:               !commander.removeComments,
+  runtime:                commander.runtime,
+  modules:                commander.modules,
   format: {
     indent: {
       style:     util.repeat(parseInt(commander.indent))
diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index 17d29b3e99..70a0b900b6 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -48,22 +48,23 @@ File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
 
   _.defaults(opts, {
-    includeRegenerator: false,
-    experimental:       false,
-    reactCompat:        false,
-    playground:         false,
-    whitespace:         true,
-    moduleIds:          opts.amdModuleIds || false,
-    blacklist:          [],
-    whitelist:          [],
-    sourceMap:          false,
-    optional:           [],
-    comments:           true,
-    filename:           "unknown",
-    modules:            "common",
-    runtime:            false,
-    code:               true,
-    ast:                true
+    keepModuleIdExtensions: false,
+    includeRegenerator:     false,
+    experimental:           false,
+    reactCompat:            false,
+    playground:             false,
+    whitespace:             true,
+    moduleIds:              opts.amdModuleIds || false,
+    blacklist:              [],
+    whitelist:              [],
+    sourceMap:              false,
+    optional:               [],
+    comments:               true,
+    filename:               "unknown",
+    modules:                "common",
+    runtime:                false,
+    code:                   true,
+    ast:                    true
   });
 
   // normalise windows path separators to unix
diff --git a/lib/6to5/transformation/modules/_default.js b/lib/6to5/transformation/modules/_default.js
index a70db37f50..5e8ceb12a7 100644
--- a/lib/6to5/transformation/modules/_default.js
+++ b/lib/6to5/transformation/modules/_default.js
@@ -156,8 +156,10 @@ DefaultFormatter.prototype.getModuleName = function () {
     filenameRelative = filenameRelative.replace(sourceRootRegEx, "");
   }
 
-  // remove extension
-  filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  if (!opts.keepModuleIdExtensions) {
+    // remove extension
+    filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  }
 
   moduleName += filenameRelative;