always use an IIFE for classes - fixes #435

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

@@ -3,36 +3,11 @@ var util     = require("../../util");
 var t        = require("../../types");
 
 exports.ClassDeclaration = function (node, parent, file, scope) {
-  var closure = true;
-  if (t.isProgram(parent) || t.isBlockStatement(parent)) {
-    closure = false;
-  }
-
-  var factory = new Class(node, file, scope, closure);
-  var newNode = factory.run();
-  if (factory.closure) {
-    if (closure) {
-      // declaration in an expression context...
-      // export default class Foo {}
-      scope.push({
-        kind: "var",
-        key: node.id.key,
-        id: node.id
-      });
-      return t.assignmentExpression("=", node.id, newNode);
-    } else {
-      // has a super class or PrivateDeclaration etc
-      return t.variableDeclaration("let", [
-        t.variableDeclarator(node.id, newNode)
-      ]);
-    }
-  } else {
-    return newNode;
-  }
+  return new Class(node, file, scope, true).run();
 };
 
 exports.ClassExpression = function (node, parent, file, scope) {
-  return new Class(node, file, scope, true).run();
+  return new Class(node, file, scope, false).run();
 };
 
 /**
@@ -44,11 +19,11 @@ exports.ClassExpression = function (node, parent, file, scope) {
  * @param {Boolean} closure
  */
 
-function Class(node, file, scope, closure) {
-  this.closure = closure;
-  this.scope   = scope;
-  this.node    = node;
-  this.file    = file;
+function Class(node, file, scope, isStatement) {
+  this.isStatement = isStatement;
+  this.scope       = scope;
+  this.node        = node;
+  this.file        = file;
 
   this.hasInstanceMutators = false;
   this.hasStaticMutators   = false;
@@ -86,8 +61,6 @@ Class.prototype.run = function () {
   //
 
   if (superName) {
-    this.closure = true;
-
     // so we're only evaluating it once
     var superRef = this.scope.generateUidBasedOnNode(superName, this.file);
     body.unshift(t.variableDeclaration("var", [
@@ -103,19 +76,25 @@ Class.prototype.run = function () {
 
   t.inheritsComments(body[0], this.node);
 
-  if (this.closure) {
-    if (body.length === 1) {
-      // only a constructor so no need for a closure container
-      return constructor;
-    } else {
-      body.push(t.returnStatement(className));
-      return t.callExpression(
-        t.functionExpression(null, [], t.blockStatement(body)),
-        []
-      );
-    }
+  var init;
+
+  if (body.length === 1) {
+    // only a constructor so no need for a closure container
+    init = constructor;
   } else {
-    return body;
+    body.push(t.returnStatement(className));
+    init = t.callExpression(
+      t.functionExpression(null, [], t.blockStatement(body)),
+      []
+    );
+  }
+
+  if (this.isStatement) {
+    return t.variableDeclaration("let", [
+      t.variableDeclarator(className, init)
+    ]);
+  } else {
+    return init;
   }
 };
 

test/fixtures/transformation/es6-classes/instance-getter-and-setter/expected.js

@@ -5,16 +5,20 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    get: function () {
-      return 5 + 5;
-    },
-    set: function (val) {
-      this._test = val;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      get: function () {
+        return 5 + 5;
+      },
+      set: function (val) {
+        this._test = val;
+      },
+      enumerable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-getter/expected.js

@@ -5,13 +5,17 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    get: function () {
-      return 5 + 5;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      get: function () {
+        return 5 + 5;
+      },
+      enumerable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-method/expected.js

@@ -1,7 +1,11 @@
 "use strict";
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-Test.prototype.test = function () {
-  return 5 + 5;
-};
+  Test.prototype.test = function () {
+    return 5 + 5;
+  };
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-setter/expected.js

@@ -5,13 +5,17 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    set: function (val) {
-      this._test = val;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      set: function (val) {
+        this._test = val;
+      },
+      enumerable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/static/expected.js

@@ -5,14 +5,18 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var A = function A() {};
+var A = (function () {
+  var A = function A() {};
 
-A.a = function () {};
+  A.a = function () {};
 
-_prototypeProperties(A, {
-  b: {
-    get: function () {},
-    set: function (b) {},
-    enumerable: true
-  }
-});
+  _prototypeProperties(A, {
+    b: {
+      get: function () {},
+      set: function (b) {},
+      enumerable: true
+    }
+  });
+
+  return A;
+})();

test/fixtures/transformation/playground/object-getter-memoization/expected.js

@@ -14,21 +14,25 @@ var _defineProperty = function (obj, key, value) {
   });
 };
 
-var Foo = function Foo() {};
+var Foo = (function () {
+  var Foo = function Foo() {};
 
-_prototypeProperties(Foo, null, _defineProperty({
-  bar: {
+  _prototypeProperties(Foo, null, _defineProperty({
+    bar: {
+      get: function () {
+        return _defineProperty(this, "bar", complex()).bar;
+      },
+      enumerable: true
+    }
+  }, bar, {
     get: function () {
-      return _defineProperty(this, "bar", complex()).bar;
+      return _defineProperty(this, bar, complex())[bar];
     },
     enumerable: true
-  }
-}, bar, {
-  get: function () {
-    return _defineProperty(this, bar, complex())[bar];
-  },
-  enumerable: true
-}));
+  }));
+
+  return Foo;
+})();
 
 var foo = Object.defineProperties({}, _defineProperty({
   bar: {

test/fixtures/transformation/source-maps/class/expected.js

@@ -5,16 +5,20 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  bar: {
-    get: function () {
-      throw new Error("wow");
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    bar: {
+      get: function () {
+        throw new Error("wow");
+      },
+      enumerable: true
+    }
+  });
+
+  return Test;
+})();
 
 var test = new Test();
 test.bar;

test/fixtures/transformation/source-maps/class/source-mappings.json

@@ -4,7 +4,7 @@
     "column": 10
   },
   "generated": {
-    "line": 13,
-    "column": 13
+    "line": 14,
+    "column": 15
   }
 }]