From 3fdf492dcf9c4edcbd61a90f851926478c7dfaf8 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sun, 25 Jan 2015 14:03:25 +1100
Subject: [PATCH] safer common interop - closes #493

---
 lib/6to5/transformation/modules/amd-strict.js |  3 --
 lib/6to5/transformation/modules/amd.js        |  2 +-
 lib/6to5/transformation/modules/common.js     | 35 +++++++------------
 .../templates/common-export-default-assign.js |  1 -
 ...lt-module.js => exports-default-assign.js} |  0
 .../exports-default-module-override.js        |  1 -
 .../templates/exports-module-declaration.js   |  1 +
 .../templates/interop-require-wildcard.js     |  2 +-
 .../templates/interop-require.js              |  2 +-
 .../es6-modules-amd/exports-from/expected.js  |  2 +-
 .../imports-default/expected.js               |  2 +-
 .../imports-mixing/expected.js                |  4 +--
 .../es6-modules-amd/overview/expected.js      | 15 ++------
 .../exports-default-non-function/expected.js  | 13 +------
 .../exports-from/expected.js                  |  2 +-
 .../imports-default/expected.js               |  2 +-
 .../imports-glob/expected.js                  |  2 +-
 .../imports-mixing/expected.js                |  2 +-
 .../es6-modules-common/overview/expected.js   |  4 +--
 .../es6-modules-umd/exports-from/expected.js  |  2 +-
 .../imports-default/expected.js               |  2 +-
 .../imports-mixing/expected.js                |  4 +--
 .../es6-modules-umd/overview/expected.js      | 15 ++------
 23 files changed, 36 insertions(+), 82 deletions(-)
 delete mode 100644 lib/6to5/transformation/modules/amd-strict.js
 delete mode 100644 lib/6to5/transformation/templates/common-export-default-assign.js
 rename lib/6to5/transformation/templates/{exports-default-module.js => exports-default-assign.js} (100%)
 delete mode 100644 lib/6to5/transformation/templates/exports-default-module-override.js
 create mode 100644 lib/6to5/transformation/templates/exports-module-declaration.js

diff --git a/lib/6to5/transformation/modules/amd-strict.js b/lib/6to5/transformation/modules/amd-strict.js
deleted file mode 100644
index a055b94763..0000000000
--- a/lib/6to5/transformation/modules/amd-strict.js
+++ /dev/null
@@ -1,3 +0,0 @@
-"use strict";
-
-module.exports = require("./_strict")(require("./amd"));
diff --git a/lib/6to5/transformation/modules/amd.js b/lib/6to5/transformation/modules/amd.js
index 9c46440cb5..cdc8252443 100644
--- a/lib/6to5/transformation/modules/amd.js
+++ b/lib/6to5/transformation/modules/amd.js
@@ -107,7 +107,7 @@ AMDFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
 };
 
 AMDFormatter.prototype.exportDeclaration = function (node) {
-  if (node.default) {
+  if (node.default && !this.noInteropRequire) {
     this.passModuleArg = true;
   }
 
diff --git a/lib/6to5/transformation/modules/common.js b/lib/6to5/transformation/modules/common.js
index 2bf7f61f1b..d8be6f82d5 100644
--- a/lib/6to5/transformation/modules/common.js
+++ b/lib/6to5/transformation/modules/common.js
@@ -20,6 +20,7 @@ function CommonJSFormatter(file) {
   var state = { hasNonDefaultExports: false };
   traverse(file.ast, visitor, file.scope, state);
 
+  this.insertedModuleDeclaration = false;
   this.hasNonDefaultExports = state.hasNonDefaultExports;
 }
 
@@ -71,33 +72,23 @@ CommonJSFormatter.prototype.exportDeclaration = function (node, nodes) {
     var declar = node.declaration;
     var assign;
 
-    // module.exports = VALUE;
-    var templateName = "exports-default-module";
-
-    // exports = module.exports = VALUE;
-    if (this.hasNonDefaultExports) templateName = "exports-default-module-override";
-
-    if (t.isFunctionDeclaration(declar) || !this.hasNonDefaultExports) {
-      assign = util.template(templateName, {
+    if (this.hasNonDefaultExports) {
+      if (!this.insertedModuleDeclaration) {
+        nodes.push(util.template("exports-module-declaration", true));
+        this.insertedModuleDeclaration = true;
+      }
+    } else {
+      var assign = util.template("exports-default-assign", {
         VALUE: this._pushStatement(declar, nodes)
       }, true);
 
-      // hoist to the top if this default is a function
-      nodes.push(this._hoistExport(declar, assign, 3));
-      return;
-    } else {
-      // this export isn't a function so we can't hoist it to the top so we need to set it
-      // at the very end of the file with something like:
-      //
-      //   module.exports = _extends(exports["default"], exports)
-      //
-
-      assign = util.template("common-export-default-assign", {
-        EXTENDS_HELPER: this.file.addHelper("extends")
-      }, true);
-      assign._blockHoist = 0;
+      if (t.isFunctionDeclaration(declar)) {
+        // we can hoist this assignment to the top of the file
+        assign._blockHoist = 3;
+      }
 
       nodes.push(assign);
+      return;
     }
   }
 
diff --git a/lib/6to5/transformation/templates/common-export-default-assign.js b/lib/6to5/transformation/templates/common-export-default-assign.js
deleted file mode 100644
index 557c221edb..0000000000
--- a/lib/6to5/transformation/templates/common-export-default-assign.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = EXTENDS_HELPER(exports["default"], exports);
diff --git a/lib/6to5/transformation/templates/exports-default-module.js b/lib/6to5/transformation/templates/exports-default-assign.js
similarity index 100%
rename from lib/6to5/transformation/templates/exports-default-module.js
rename to lib/6to5/transformation/templates/exports-default-assign.js
diff --git a/lib/6to5/transformation/templates/exports-default-module-override.js b/lib/6to5/transformation/templates/exports-default-module-override.js
deleted file mode 100644
index 4ce92a4fd1..0000000000
--- a/lib/6to5/transformation/templates/exports-default-module-override.js
+++ /dev/null
@@ -1 +0,0 @@
-exports = module.exports = VALUE;
diff --git a/lib/6to5/transformation/templates/exports-module-declaration.js b/lib/6to5/transformation/templates/exports-module-declaration.js
new file mode 100644
index 0000000000..32b83d4a5a
--- /dev/null
+++ b/lib/6to5/transformation/templates/exports-module-declaration.js
@@ -0,0 +1 @@
+exports.__esModule = true;
diff --git a/lib/6to5/transformation/templates/interop-require-wildcard.js b/lib/6to5/transformation/templates/interop-require-wildcard.js
index 89287917c8..92ade67d5c 100644
--- a/lib/6to5/transformation/templates/interop-require-wildcard.js
+++ b/lib/6to5/transformation/templates/interop-require-wildcard.js
@@ -1,3 +1,3 @@
 (function (obj) {
-  return obj && obj.constructor === Object ? obj : { default: obj };
+  return obj && obj.__esModule ? obj.default : { default: obj };
 })
diff --git a/lib/6to5/transformation/templates/interop-require.js b/lib/6to5/transformation/templates/interop-require.js
index b48ee8c30e..55911c817c 100644
--- a/lib/6to5/transformation/templates/interop-require.js
+++ b/lib/6to5/transformation/templates/interop-require.js
@@ -1,3 +1,3 @@
 (function (obj) {
-  return obj && (obj["default"] || obj);
+  return obj && obj.__esModule ? obj.default : obj;
 })
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
index 374e2f4043..7601d9d483 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
@@ -2,7 +2,7 @@ define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var _interopRequireWildcard = function (obj) {
-    return obj && obj.constructor === Object ? obj : {
+    return obj && obj.__esModule ? obj["default"] : {
       "default": obj
     };
   };
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
index bcc4b497c9..b983b462ed 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
@@ -2,7 +2,7 @@ define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
index 8acd23bf34..8d9fb05272 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
@@ -2,10 +2,10 @@ define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
 
   var xyz = _foo.baz;
-});
\ No newline at end of file
+});
diff --git a/test/fixtures/transformation/es6-modules-amd/overview/expected.js b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
index 563f241fd3..b8ed01c2b6 100644
--- a/test/fixtures/transformation/es6-modules-amd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
@@ -1,19 +1,8 @@
 define(["exports", "module", "foo", "foo-bar", "./directory/foo-bar"], function (exports, module, _foo, _fooBar, _directoryFooBar) {
   "use strict";
 
-  var _extends = function (target) {
-    for (var i = 1; i < arguments.length; i++) {
-      var source = arguments[i];
-      for (var key in source) {
-        target[key] = source[key];
-      }
-    }
-
-    return target;
-  };
-
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
@@ -24,6 +13,6 @@ define(["exports", "module", "foo", "foo-bar", "./directory/foo-bar"], function
   exports.test = test;
   var test2 = exports.test2 = 5;
 
+  exports.__esModule = true;
   exports["default"] = test;
-  module.exports = _extends(exports["default"], exports);
 });
diff --git a/test/fixtures/transformation/es6-modules-common/exports-default-non-function/expected.js b/test/fixtures/transformation/es6-modules-common/exports-default-non-function/expected.js
index a8d178e952..0f6c24422b 100644
--- a/test/fixtures/transformation/es6-modules-common/exports-default-non-function/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/exports-default-non-function/expected.js
@@ -1,17 +1,6 @@
 "use strict";
 
-var _extends = function (target) {
-  for (var i = 1; i < arguments.length; i++) {
-    var source = arguments[i];
-    for (var key in source) {
-      target[key] = source[key];
-    }
-  }
-
-  return target;
-};
-
 exports.Cachier = Cachier;
+exports.__esModule = true;
 exports["default"] = new Cachier();
 function Cachier(databaseName) {}
-module.exports = _extends(exports["default"], exports);
diff --git a/test/fixtures/transformation/es6-modules-common/exports-from/expected.js b/test/fixtures/transformation/es6-modules-common/exports-from/expected.js
index 5a4b431d17..690de1d0fa 100644
--- a/test/fixtures/transformation/es6-modules-common/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/exports-from/expected.js
@@ -1,7 +1,7 @@
 "use strict";
 
 var _interopRequireWildcard = function (obj) {
-  return obj && obj.constructor === Object ? obj : {
+  return obj && obj.__esModule ? obj["default"] : {
     "default": obj
   };
 };
diff --git a/test/fixtures/transformation/es6-modules-common/imports-default/expected.js b/test/fixtures/transformation/es6-modules-common/imports-default/expected.js
index 02c8997cb6..1a287b128a 100644
--- a/test/fixtures/transformation/es6-modules-common/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/imports-default/expected.js
@@ -1,7 +1,7 @@
 "use strict";
 
 var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
+  return obj && obj.__esModule ? obj["default"] : obj;
 };
 
 var foo = _interopRequire(require("foo"));
diff --git a/test/fixtures/transformation/es6-modules-common/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-common/imports-glob/expected.js
index d885f06222..b6b74312f4 100644
--- a/test/fixtures/transformation/es6-modules-common/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/imports-glob/expected.js
@@ -1,7 +1,7 @@
 "use strict";
 
 var _interopRequireWildcard = function (obj) {
-  return obj && obj.constructor === Object ? obj : {
+  return obj && obj.__esModule ? obj["default"] : {
     "default": obj
   };
 };
diff --git a/test/fixtures/transformation/es6-modules-common/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-common/imports-mixing/expected.js
index 09ea4cec86..2ea5ac36b3 100644
--- a/test/fixtures/transformation/es6-modules-common/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/imports-mixing/expected.js
@@ -1,7 +1,7 @@
 "use strict";
 
 var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
+  return obj && obj.__esModule ? obj["default"] : obj;
 };
 
 var foo = _interopRequire(require("foo"));
diff --git a/test/fixtures/transformation/es6-modules-common/overview/expected.js b/test/fixtures/transformation/es6-modules-common/overview/expected.js
index a15f34dd81..dfe2d85e62 100644
--- a/test/fixtures/transformation/es6-modules-common/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-common/overview/expected.js
@@ -1,13 +1,13 @@
 "use strict";
 
 var _interopRequireWildcard = function (obj) {
-  return obj && obj.constructor === Object ? obj : {
+  return obj && obj.__esModule ? obj["default"] : {
     "default": obj
   };
 };
 
 var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
+  return obj && obj.__esModule ? obj["default"] : obj;
 };
 
 require("foo");
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
index 2b8ca3d179..15f8cabf4c 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
@@ -8,7 +8,7 @@
   "use strict";
 
   var _interopRequireWildcard = function (obj) {
-    return obj && obj.constructor === Object ? obj : {
+    return obj && obj.__esModule ? obj["default"] : {
       "default": obj
     };
   };
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
index 30aa739b11..9dffd5ee3e 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
@@ -8,7 +8,7 @@
   "use strict";
 
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
index f677ceee86..85c3161db2 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
@@ -8,10 +8,10 @@
   "use strict";
 
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
 
   var xyz = _foo.baz;
-});
\ No newline at end of file
+});
diff --git a/test/fixtures/transformation/es6-modules-umd/overview/expected.js b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
index adbd4539cc..efc240bcf5 100644
--- a/test/fixtures/transformation/es6-modules-umd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
@@ -7,19 +7,8 @@
 })(function (exports, module, _foo, _fooBar, _directoryFooBar) {
   "use strict";
 
-  var _extends = function (target) {
-    for (var i = 1; i < arguments.length; i++) {
-      var source = arguments[i];
-      for (var key in source) {
-        target[key] = source[key];
-      }
-    }
-
-    return target;
-  };
-
   var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
+    return obj && obj.__esModule ? obj["default"] : obj;
   };
 
   var foo = _interopRequire(_foo);
@@ -30,6 +19,6 @@
   exports.test = test;
   var test2 = exports.test2 = 5;
 
+  exports.__esModule = true;
   exports["default"] = test;
-  module.exports = _extends(exports["default"], exports);
 });