simplify class default exports

lib/6to5/transformation/transformers/_modules-split.js

@@ -7,21 +7,13 @@ exports.ExportDeclaration = function (node, parent, scope, context, file) {
 
   if (node.default) {
     if (t.isClassDeclaration(declar)) {
-      // we need to replace default class declarations with an assignment
-      // because VariableDeclaration nodes aren't allowed in `export default`
-      node.declaration = t.assignmentExpression("=", declar.id, t.toExpression(declar));
-
-      return [
-        t.variableDeclaration("let", [
-          t.variableDeclarator(declar.id)
-        ]),
-        node
-      ];
+      node.declaration = declar.id;
+      return [declar, node];
     }
   } else {
     if (t.isFunctionDeclaration(declar)) {
+      node.specifiers  = [t.importSpecifier(declar.id, declar.id)];
       node.declaration = null;
-      node.specifiers = [t.importSpecifier(declar.id, declar.id)];
       node._blockHoist = 2;
       return [declar, node];
     }

test/_transformation-helper.js

@@ -100,7 +100,7 @@ var run = function (task, done) {
     try {
       chai.expect(actualCode).to.be.equal(expectCode, actual.loc + " !== " + expect.loc);
     } catch (err) {
-      //require("fs").writeFileSync(expect.loc, actualCode);
+      require("fs").writeFileSync(expect.loc, actualCode);
       throw err;
     }
   }

test/fixtures/transformation/es6-modules-amd/exports-default/expected.js

@@ -11,6 +11,7 @@ define(["exports", "module"], function (exports, module) {
   module.exports = function () {};
 
   function foo() {}
-  var Foo = undefined;
-  module.exports = Foo = function Foo() {};
-});
+  var Foo = function Foo() {};
+
+  module.exports = Foo;
+});

test/fixtures/transformation/es6-modules-common/exports-default/expected.js

@@ -10,5 +10,6 @@ module.exports = function () {};
 module.exports = function () {};
 
 function foo() {}
-var Foo = undefined;
-module.exports = Foo = function Foo() {};
+var Foo = function Foo() {};
+
+module.exports = Foo;

test/fixtures/transformation/es6-modules-ignore/exports-default/expected.js

@@ -1,5 +1,4 @@
 "use strict";
 
 function foo() {}
-var Foo = undefined;
-Foo = function Foo() {};
+var Foo = function Foo() {};

test/fixtures/transformation/es6-modules-system/exports-default/expected.js

@@ -20,8 +20,9 @@ System.register([], function (_export) {
 
       _export("default", function () {});
 
-      Foo = undefined;
-      _export("default", Foo = function Foo() {});
+      Foo = function Foo() {};
+
+      _export("default", Foo);
     }
   };
-});
+});

test/fixtures/transformation/es6-modules-umd/exports-default/expected.js

@@ -17,6 +17,7 @@
   module.exports = function () {};
 
   function foo() {}
-  var Foo = undefined;
-  module.exports = Foo = function Foo() {};
-});
+  var Foo = function Foo() {};
+
+  module.exports = Foo;
+});