add optional to keep module id extensions - fixes #420

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

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;