add optional to keep module id extensions - fixes #420

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) {
@@ -101,6 +102,7 @@ if (errors.length) {
 //
 
 exports.opts = {
+  keepModuleIdExtensions: commander.keepModuleIdExtensions,
   includeRegenerator:     commander.includeRegenerator,
   sourceMapName:          commander.outFile,
   experimental:           commander.experimental,

lib/6to5/file.js

@@ -48,6 +48,7 @@ File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
 
   _.defaults(opts, {
+    keepModuleIdExtensions: false,
     includeRegenerator:     false,
     experimental:           false,
     reactCompat:            false,

lib/6to5/transformation/modules/_default.js

@@ -156,8 +156,10 @@ DefaultFormatter.prototype.getModuleName = function () {
     filenameRelative = filenameRelative.replace(sourceRootRegEx, "");
   }
 
+  if (!opts.keepModuleIdExtensions) {
     // remove extension
     filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  }
 
   moduleName += filenameRelative;