export as module.exports if there are no other ExportDeclarations in commonInterop module formatter @guybedford

doc/modules.md

@@ -51,6 +51,69 @@ var test = 5; exports.test = test;
 exports.default = test;
 ```
 
+### Common interop
+
+**In**
+
+```javascript
+import "foo";
+
+import foo from "foo";
+import * as foo from "foo";
+
+import {bar} from "foo";
+import {foo as bar} from "foo";
+
+export {test};
+export var test = 5;
+
+export default test;
+```
+
+**Out**
+
+```javascript
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+require("foo");
+
+var foo = _interopRequire(require("foo"));
+var foo = require("foo");
+
+var bar = require("foo").bar;
+var bar = require("foo").foo;
+
+exports.test = test;
+var test = exports.test = 5;
+
+exports["default"] = test;
+```
+
+#### module.exports behaviour
+
+If there exist no other non-default `export`s then `default exports` are
+exported as `module.exports` instead of `exports.default`.
+
+**In**
+
+```javascript
+export default function foo() {
+
+}
+```
+
+**Out**
+
+```javascript
+module.exports = foo;
+
+function foo() {
+
+}
+```
+
 ### AMD
 
 **In**

lib/6to5/templates/exports-default-module.js

@@ -0,0 +1 @@
+module.exports = VALUE;

lib/6to5/transformation/modules/common-interop.js

@@ -3,9 +3,11 @@ module.exports = CommonJSInteropFormatter;
 var CommonJSFormatter = require("./common");
 var util              = require("../../util");
 var t                 = require("../../types");
+var _                 = require("lodash");
 
 function CommonJSInteropFormatter(file) {
-  this.file = file;
+  this.has = false;
+  CommonJSFormatter.apply(this, arguments);
 }
 
 util.inherits(CommonJSInteropFormatter, CommonJSFormatter);
@@ -26,3 +28,27 @@ CommonJSInteropFormatter.prototype.importSpecifier = function (specifier, node,
     CommonJSFormatter.prototype.importSpecifier.apply(this, arguments);
   }
 };
+
+CommonJSInteropFormatter.prototype.export = function (node, nodes, parent) {
+  if (node.default && !this.has) {
+    var declar = node.declaration;
+
+    // module.exports = VALUE;
+    var assign = util.template("exports-default-module", {
+      VALUE: this._pushStatement(declar, nodes)
+    }, true);
+
+    // hoist to the top if this default is a function
+    nodes.push(this._hoistExport(declar, assign));
+    return;
+  } else {
+    this.has = true;
+  }
+
+  CommonJSFormatter.prototype.export.apply(this, arguments);
+};
+
+CommonJSInteropFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
+  this.has = true;
+  CommonJSFormatter.prototype.exportSpecifier.apply(this, arguments);
+};

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

@@ -38,23 +38,32 @@ CommonJSFormatter.prototype.importSpecifier = function (specifier, node, nodes)
   }));
 };
 
+CommonJSFormatter.prototype._hoistExport = function (declar, assign) {
+  if (t.isFunctionDeclaration(declar)) {
+    assign._blockHoist = true;
+  }
+
+  return assign;
+};
+
+CommonJSFormatter.prototype._pushStatement = function (ref, nodes) {
+  if (t.isClass(ref) || t.isFunction(ref)) {
+    if (ref.id) {
+      nodes.push(t.toStatement(ref));
+      ref = ref.id;
+    }
+  }
+  return ref;
+};
+
 CommonJSFormatter.prototype.export = function (node, nodes) {
   var declar = node.declaration;
 
   if (node.default) {
-    var ref = declar;
-
-    if (t.isClass(ref) || t.isFunction(ref)) {
-      if (ref.id) {
-        nodes.push(t.toStatement(ref));
-        ref = ref.id;
-      }
-    }
-
     nodes.push(util.template("exports-default", {
       //inherits: node,
 
-      VALUE: ref
+      VALUE: this._pushStatement(declar, nodes)
     }, true));
   } else {
     var assign;
@@ -83,9 +92,7 @@ CommonJSFormatter.prototype.export = function (node, nodes) {
       nodes.push(t.toStatement(declar));
       nodes.push(assign);
 
-      if (t.isFunctionDeclaration(declar)) {
-        assign._blockHoist = true;
-      }
+      this._hoistExport(declar, assign);
     }
   }
 };
@@ -126,7 +133,7 @@ CommonJSFormatter.prototype._exportSpecifier = function (getRef, specifier, node
 };
 
 CommonJSFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
-  return this._exportSpecifier(function () {
+  this._exportSpecifier(function () {
     return t.callExpression(t.identifier("require"), [node.source]);
   }, specifier, node, nodes);
 };

lib/6to5/transformation/transformers/es6-modules.js

@@ -5,10 +5,10 @@ exports.ImportDeclaration = function (node, parent, file) {
 
   if (node.specifiers.length) {
     _.each(node.specifiers, function (specifier) {
-      file.moduleFormatter.importSpecifier(specifier, node, nodes);
+      file.moduleFormatter.importSpecifier(specifier, node, nodes, parent);
     });
   } else {
-    file.moduleFormatter.import(node, nodes);
+    file.moduleFormatter.import(node, nodes, parent);
   }
 
   return nodes;
@@ -18,10 +18,10 @@ exports.ExportDeclaration = function (node, parent, file) {
   var nodes = [];
 
   if (node.declaration) {
-    file.moduleFormatter.export(node, nodes);
+    file.moduleFormatter.export(node, nodes, parent);
   } else {
     _.each(node.specifiers, function (specifier) {
-      file.moduleFormatter.exportSpecifier(specifier, node, nodes);
+      file.moduleFormatter.exportSpecifier(specifier, node, nodes, parent);
     });
   }
 

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

@@ -1,13 +1,13 @@
 "use strict";
 
-exports["default"] = 42;
-exports["default"] = {};
-exports["default"] = [];
-exports["default"] = foo;
-exports["default"] = function () {};
-exports["default"] = function () {};
+module.exports = foo;
+module.exports = 42;
+module.exports = {};
+module.exports = [];
+module.exports = foo;
+module.exports = function () {};
+module.exports = function () {};
 function foo() {}
-exports["default"] = foo;
 var Foo = function Foo() {};
 
-exports["default"] = Foo;
+module.exports = Foo;

test/fixtures/transformation/es6-rest-parameters/arrow-functions/expected.js

@@ -1,6 +1,5 @@
 "use strict";
 
-var _arguments = arguments;
 var _argumentsToArray = function (args) {
   var target = new Array(args.length);
   for (var i = 0; i < args.length; i++) {
@@ -11,5 +10,5 @@ var _argumentsToArray = function (args) {
 };
 
 var concat = function () {
-  var arrs = _argumentsToArray(_arguments);
+  var arrs = _argumentsToArray(arguments);
 };