add moduleId option for specifying a custom module id

lib/babel/transformation/file.js

@@ -89,7 +89,7 @@ File.validOptions = [
   "compact",
 
   "resolveModuleSource",
-  "getModuleName",
+  "moduleId",
 
   // legacy
   "format",
@@ -138,6 +138,10 @@ File.prototype.normalizeOptions = function (opts) {
     opts.sourceRoot = slash(opts.sourceRoot);
   }
 
+  if (opts.moduleId) {
+    opts.moduleIds = true;
+  }
+
   opts.basename = path.basename(opts.filename, path.extname(opts.filename));
 
   opts.blacklist = util.arrayify(opts.blacklist);

lib/babel/transformation/modules/_default.js

@@ -146,7 +146,7 @@ DefaultFormatter.prototype.isLocalReference = function (node, scope) {
 
 DefaultFormatter.prototype.getModuleName = function () {
   var opts = this.file.opts;
-  if (opts.getModuleName) return opts.getModuleName(opts.filename);
+  if (opts.moduleId) return opts.moduleId;
 
   var filenameRelative = opts.filenameRelative;
   var moduleName = "";