make system module formatter modules anonymous by default - fixes #347

lib/6to5/file.js

@@ -35,6 +35,7 @@ File.normaliseOptions = function (opts) {
     experimental: false,
     playground:   false,
     whitespace:   true,
+    moduleIds:    opts.amdModuleIds || false,
     blacklist:    [],
     whitelist:    [],
     sourceMap:    false,

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

@@ -55,7 +55,7 @@ AMDFormatter.prototype.transform = function (ast) {
  */
 
 AMDFormatter.prototype.getModuleName = function () {
-  if (this.file.opts.amdModuleIds) {
+  if (this.file.opts.moduleIds) {
     return DefaultFormatter.prototype.getModuleName.apply(this, arguments);
   } else {
     return null;

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

@@ -12,14 +12,10 @@ function SystemFormatter(file) {
   this.noInteropRequire = true;
 
   AMDFormatter.apply(this, arguments);
-
-  this.moduleNameLiteral = t.literal(this.getModuleName());
 }
 
 util.inherits(SystemFormatter, AMDFormatter);
 
-SystemFormatter.prototype.getModuleName = DefaultFormatter.prototype.getModuleName;
-
 SystemFormatter.prototype._exportsWildcard = function (objectIdentifier) {
   var leftIdentifier = t.identifier("i");
   var valIdentifier  = t.memberExpression(objectIdentifier, leftIdentifier, true);
@@ -67,8 +63,11 @@ SystemFormatter.prototype.buildRunnerSetters = function () {
 SystemFormatter.prototype.transform = function (ast) {
   var program = ast.program;
 
+  var moduleName = this.getModuleName();
+  var moduleNameLiteral = t.literal(moduleName);
+
   var runner = util.template("system", {
-    MODULE_NAME: this.moduleNameLiteral,
+    MODULE_NAME: moduleNameLiteral,
     MODULE_DEPENDENCIES: t.arrayExpression(this.buildDependencyLiterals()),
     EXPORT_IDENTIFIER: this.exportIdentifier,
     SETTERS: this.buildRunnerSetters(),
@@ -76,6 +75,8 @@ SystemFormatter.prototype.transform = function (ast) {
   }, true);
 
   var handlerBody = runner.expression.arguments[2].body.body;
+  if (!moduleName) runner.expression.arguments.shift();
+
   var returnStatement = handlerBody.pop();
 
   // hoist up function declarations for circular references