add getModuleName option - fixes #844

lib/babel/transformation/file.js

@@ -86,10 +86,12 @@ File.validOptions = [
   "format",
   "playground",
   "experimental",
-  "resolveModuleSource",
   "externalHelpers",
   "auxiliaryComment",
 
+  "resolveModuleSource",
+  "getModuleName",
+
   // these are used by plugins
   "ignore",
   "only",

lib/babel/transformation/modules/_default.js

@@ -146,6 +146,8 @@ DefaultFormatter.prototype.isLocalReference = function (node, scope) {
 
 DefaultFormatter.prototype.getModuleName = function () {
   var opts = this.file.opts;
+  if (opts.getModuleName) return opts.getModuleName(opts.filename);
+
   var filenameRelative = opts.filenameRelative;
   var moduleName = "";