v2.11.0

Whitelist constructors aliasable to core-js

CHANGELOG.md

@@ -11,6 +11,26 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 2.11.0
+
+ * **Bug Fix**
+  * Fix unnecessary IIFE in default parameters on method calls.
+  * Add support for supers inside of closures.
+ * **New Feature**
+  * Add `--keep-module-id-extensions`/`keepModuleIdExtensions` option to keep extensions in module ids.
+ * **Polish**
+  * Special case single argument spread properties in `super` inside classes.
+  * Don't use a variable declaration for class declaration IFFE.
+  * Rename `inherits` helper parameters.
+  * `coreAliasing` transformer now aliases `Promise`, `Set`, `Map` and more. Thanks [@AluisioASG](https://github.com/AluisioASG).
+
+## 2.10.1
+
+ * **Internal**
+  * Upgrade `core-js` to `0.4.4`.
+ * **New Feature**
+  * Added `--include-regenerator` option to CLI and `includeRegenerator` option to API that includes the regenerator runtime if necessary.
+
 ## 2.10.0
 
  * **New Feature**

NOTES.md

@@ -10,3 +10,4 @@
  * Split up ES5 getter/setter transforming and ES6 property methods into separate transformers.
  * Add autoindentation.
  * Move `super` transformation from classes into a separate transformer that also supports object expressions.
+ * Prefix all fast transformers with `fast`, make them declare that they're a fast transformer similar to optional transformers and add a `--fast` flag to enable them all.

bin/6to5/index.js

@@ -25,6 +25,8 @@ commander.option("-I, --indent [width]", "Indent width [2]", 2);
 commander.option("-a, --amd-module-ids", "Insert module id in AMD modules", false); // todo: remove in 3.0.0
 commander.option("-m, --module-ids", "Insert module id in modules", false);
 commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
+commander.option("-E, --include-regenerator", "Include the regenerator runtime if necessary", false);
+commander.option("--keep-module-id-extensions", "Keep extensions when generating module ids", false);
 
 commander.on("--help", function(){
   var outKeys = function (title, obj) {
@@ -100,18 +102,20 @@ if (errors.length) {
 //
 
 exports.opts = {
-  sourceMapName: commander.outFile,
-  experimental:  commander.experimental,
-  playground:    commander.playground,
-  moduleIds:     commander.amdModuleIds || commander.moduleIds,
-  blacklist:     commander.blacklist,
-  whitelist:     commander.whitelist,
-  sourceMap:     commander.sourceMaps || commander.sourceMapsInline,
-  optional:      commander.optional,
-  comments:      !commander.removeComments,
-  runtime:       commander.runtime,
-  modules:       commander.modules,
-  reactCompat:   commander.reactCompat,
+  keepModuleIdExtensions: commander.keepModuleIdExtensions,
+  includeRegenerator:     commander.includeRegenerator,
+  sourceMapName:          commander.outFile,
+  experimental:           commander.experimental,
+  reactCompat:            commander.reactCompat,
+  playground:             commander.playground,
+  moduleIds:              commander.amdModuleIds || commander.moduleIds,
+  blacklist:              commander.blacklist,
+  whitelist:              commander.whitelist,
+  sourceMap:              commander.sourceMaps || commander.sourceMapsInline,
+  optional:               commander.optional,
+  comments:               !commander.removeComments,
+  runtime:                commander.runtime,
+  modules:                commander.modules,
   format: {
     indent: {
       style:     util.repeat(parseInt(commander.indent))

lib/6to5/file.js

@@ -48,21 +48,23 @@ File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
 
   _.defaults(opts, {
-    experimental: false,
-    reactCompat:  false,
-    playground:   false,
-    whitespace:   true,
-    moduleIds:    opts.amdModuleIds || false,
-    blacklist:    [],
-    whitelist:    [],
-    sourceMap:    false,
-    optional:     [],
-    comments:     true,
-    filename:     "unknown",
-    modules:      "common",
-    runtime:      false,
-    code:         true,
-    ast:          true
+    keepModuleIdExtensions: false,
+    includeRegenerator:     false,
+    experimental:           false,
+    reactCompat:            false,
+    playground:             false,
+    whitespace:             true,
+    moduleIds:              opts.amdModuleIds || false,
+    blacklist:              [],
+    whitelist:              [],
+    sourceMap:              false,
+    optional:               [],
+    comments:               true,
+    filename:               "unknown",
+    modules:                "common",
+    runtime:                false,
+    code:                   true,
+    ast:                    true
   });
 
   // normalise windows path separators to unix

lib/6to5/generation/generator.js

@@ -125,7 +125,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
 
     var lines = 0;
 
-    if (node.start != null) {
+    if (node.start != null && !node._ignoreUserWhitespace) {
       // user node
       if (leading) {
         lines = self.whitespace.getNewlinesBefore(node);

lib/6to5/generation/node/whitespace.js

@@ -62,11 +62,15 @@ _.each({
   CallExpression: { after: 1 },
   Literal: { after: 1 }
 }, function (amounts, type) {
-  if (_.isNumber(amounts)) amounts = { after: amounts, before: amounts };
+  if (_.isNumber(amounts)) {
+    amounts = { after: amounts, before: amounts };
+  }
 
-  _.each(amounts, function (amount, key) {
-    exports[key].nodes[type] = function () {
-      return amount;
-    };
+  _.each([type].concat(t.FLIPPED_ALIAS_KEYS[type] || []), function (type) {
+    _.each(amounts, function (amount, key) {
+      exports[key].nodes[type] = function () {
+        return amount;
+      };
+    });
   });
 });

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

@@ -156,8 +156,10 @@ DefaultFormatter.prototype.getModuleName = function () {
     filenameRelative = filenameRelative.replace(sourceRootRegEx, "");
   }
 
-  // remove extension
-  filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  if (!opts.keepModuleIdExtensions) {
+    // remove extension
+    filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  }
 
   moduleName += filenameRelative;
 

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

@@ -31,15 +31,17 @@ UMDFormatter.prototype.transform = function (ast) {
 
   var factory = t.functionExpression(null, args, t.blockStatement(body));
 
-  // runner
+  // amd
 
   var defineArgs = [t.literal("exports")];
   if (this.passModuleArg) defineArgs.push(t.literal("module"));
   defineArgs = defineArgs.concat(names);
   defineArgs = [t.arrayExpression(defineArgs)];
 
+  // common
+
   var testExports = util.template("test-exports");
-  var testModule = util.template("test-module");
+  var testModule  = util.template("test-module");
   var commonTests = this.passModuleArg ? t.logicalExpression("&&", testExports, testModule) : testExports;
 
   var commonArgs = [t.identifier("exports")];
@@ -48,6 +50,12 @@ UMDFormatter.prototype.transform = function (ast) {
     return t.callExpression(t.identifier("require"), [name]);
   }));
 
+  // globals
+
+  //var umdArgs = [];
+
+  //
+
   var moduleName = this.getModuleName();
   if (moduleName) defineArgs.unshift(t.literal(moduleName));
 

lib/6to5/transformation/templates/inherits.js

@@ -1,14 +1,14 @@
-(function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+(function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 })

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

@@ -50,16 +50,20 @@ Class.prototype.run = function () {
 
   var body = this.body = [];
 
-  var constructor = t.functionExpression(null, [], t.blockStatement([]));
-  if (this.node.id) constructor.id = className;
+  var constructor;
+  if (this.node.id) {
+    constructor = t.functionDeclaration(className, [], t.blockStatement([]));
+    body.push(constructor);
+  } else {
+    constructor = t.functionExpression(null, [], t.blockStatement([]));
+    body.push(t.variableDeclaration("var", [
+      t.variableDeclarator(className, constructor)
+    ]));
+  }
   this.constructor = constructor;
 
-  body.push(t.variableDeclaration("let", [
-    t.variableDeclarator(className, constructor)
-  ]));
-
-  var closureArgs = [];
   var closureParams = [];
+  var closureArgs = [];
 
   //
 
@@ -85,7 +89,7 @@ Class.prototype.run = function () {
 
   if (body.length === 1) {
     // only a constructor so no need for a closure container
-    init = constructor;
+    init = t.toExpression(constructor);
   } else {
     body.push(t.returnStatement(className));
     init = t.callExpression(
@@ -225,54 +229,85 @@ Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
   var method = methodNode.value;
   var self   = this;
 
-  traverse(method, {
-    enter: function (node, parent) {
-      var property;
-      var computed;
-      var args;
+  var topLevelThisReference;
 
-      if (t.isIdentifier(node, { name: "super" })) {
-        if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
-          throw self.file.errorWithNode(node, "illegal use of bare super");
+  traverse2(method, true);
+
+  if (topLevelThisReference) {
+    method.body.body.unshift(t.variableDeclaration("var", [
+      t.variableDeclarator(topLevelThisReference, t.thisExpression())
+    ]));
+  }
+
+  function traverse2(node, topLevel) {
+    traverse(node, {
+      enter: function (node, parent) {
+        if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
+          traverse2(node, false);
+          return this.skip();
         }
-      } else if (t.isCallExpression(node)) {
-        var callee = node.callee;
-        if (t.isIdentifier(callee, { name: "super" })) {
-          // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
-          property = methodNode.key;
-          computed = methodNode.computed;
-          args = node.arguments;
-        } else {
-          if (!t.isMemberExpression(callee)) return;
-          if (callee.object.name !== "super") return;
 
-          // super.test(); -> _get(Object.getPrototypeOf(ClassName.prototype), "test", this).call(this);
-          property = callee.property;
-          computed = callee.computed;
-          args = node.arguments;
+        var property;
+        var computed;
+        var args;
+
+        if (t.isIdentifier(node, { name: "super" })) {
+          if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
+            throw self.file.errorWithNode(node, "illegal use of bare super");
+          }
+        } else if (t.isCallExpression(node)) {
+          var callee = node.callee;
+          if (t.isIdentifier(callee, { name: "super" })) {
+            // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
+            property = methodNode.key;
+            computed = methodNode.computed;
+            args = node.arguments;
+          } else {
+            if (!t.isMemberExpression(callee)) return;
+            if (callee.object.name !== "super") return;
+
+            // super.test(); -> _get(Object.getPrototypeOf(ClassName.prototype), "test", this).call(this);
+            property = callee.property;
+            computed = callee.computed;
+            args = node.arguments;
+          }
+        } else if (t.isMemberExpression(node)) {
+          if (!t.isIdentifier(node.object, { name: "super" })) return;
+
+          // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
+          property = node.property;
+          computed = node.computed;
         }
-      } else if (t.isMemberExpression(node)) {
-        if (!t.isIdentifier(node.object, { name: "super" })) return;
 
-        // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
-        property = node.property;
-        computed = node.computed;
-      }
+        if (property) {
+          var thisReference;
+          if (topLevel) {
+            thisReference = t.thisExpression();
+          } else {
+            topLevelThisReference = thisReference = topLevelThisReference || self.file.generateUidIdentifier("this");
+          }
 
-      if (property) {
-        var thisExpression = t.thisExpression();
-        var superProperty = self.superProperty(property, methodNode.static, computed, thisExpression);
-        if (args) {
-          return t.callExpression(
-            t.memberExpression(superProperty, t.identifier("call"), false),
-            [thisExpression].concat(args)
-          );
-        } else {
-          return superProperty;
+          var superProperty = self.superProperty(property, methodNode.static, computed, thisReference);
+          if (args) {
+            if (args.length === 1 && t.isSpreadElement(args[0])) {
+              // super(...arguments);
+              return t.callExpression(
+                t.memberExpression(superProperty, t.identifier("apply"), false),
+                [thisReference, args[0].argument]
+              );
+            } else {
+              return t.callExpression(
+                t.memberExpression(superProperty, t.identifier("call"), false),
+                [thisReference].concat(args)
+              );
+            }
+          } else {
+            return superProperty;
+          }
         }
       }
-    }
-  });
+    });
+  }
 };
 
 /**
@@ -294,8 +329,9 @@ Class.prototype.pushConstructor = function (method) {
   t.inherits(construct, fn);
   t.inheritsComments(construct, method);
 
-  construct.defaults = fn.defaults;
-  construct.params   = fn.params;
-  construct.body     = fn.body;
-  construct.rest     = fn.rest;
+  construct._ignoreUserWhitespace = true;
+  construct.defaults              = fn.defaults;
+  construct.params                = fn.params;
+  construct.body                  = fn.body;
+  construct.rest                  = fn.rest;
 };

lib/6to5/transformation/transformers/es6-default-parameters.js

@@ -31,7 +31,7 @@ exports.Function = function (node, parent, file, scope) {
           throw file.errorWithNode(node, "Temporal dead zone - accessing a variable before it's initialized");
         }
 
-        if (scope.has(node.name)) {
+        if (scope.has(node.name, true)) {
           iife = true;
         }
       };

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

@@ -1,3 +1,9 @@
+var regenerator = require("regenerator");
+
 exports.ast = {
-  before: require("regenerator").transform
+  before: function (ast, file) {
+    regenerator.transform(ast, {
+      includeRuntime: file.opts.includeRegenerator && "if used"
+    });
+  }
 };

lib/6to5/transformation/transformers/es6-let-scoping.js

@@ -37,6 +37,7 @@ exports.VariableDeclaration = function (node, parent) {
 exports.Loop = function (node, parent, file, scope) {
   var init = node.left || node.init;
   if (isLet(init, node)) {
+    t.ensureBlock(node);
     node.body._letDeclars = [init];
   }
 

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -8,6 +8,16 @@ var coreHas = function (node) {
   return node.name !== "_" && _.has(core, node.name);
 };
 
+var ALIASABLE_CONSTRUCTORS = [
+  "Symbol",
+  "Promise",
+  "Map",
+  "WeakMap",
+  "Set",
+  "WeakSet",
+  "Dict",
+];
+
 exports.optional = true;
 
 exports.ast = {
@@ -31,8 +41,8 @@ exports.ast = {
             this.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && node.name === "Symbol") {
-          // new Symbol -> new _core.Symbol
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && _.contains(ALIASABLE_CONSTRUCTORS, node.name)) {
+          // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)

lib/6to5/transformation/transformers/react.js

@@ -42,6 +42,7 @@ var isTag = function(tagName) {
 
 exports.XJSOpeningElement = {
   exit: function (node, parent, file) {
+    console.log(node);
     var reactCompat = file.opts.reactCompat;
     var tagExpr = node.name;
     var args = [];
@@ -61,11 +62,16 @@ exports.XJSOpeningElement = {
       }
     }
 
-    var props = node.attributes;
-    if (props.length) {
+    var attribs = node.attributes;
+    if (attribs.length) {
       var _props = [];
       var objs = [];
 
+      // so basically in order to support spread elements we
+      // loop over all the attributes, breaking on spreads
+      // we then push a new object containing all prior attributes
+      // to an array for later processing
+
       var pushProps = function () {
         if (!_props.length) return;
 
@@ -73,8 +79,8 @@ exports.XJSOpeningElement = {
         _props = [];
       };
 
-      while (props.length) {
-        var prop = props.shift();
+      while (attribs.length) {
+        var prop = attribs.shift();
         if (t.isXJSSpreadAttribute(prop)) {
           pushProps();
           objs.push(prop.argument);
@@ -86,22 +92,25 @@ exports.XJSOpeningElement = {
       pushProps();
 
       if (objs.length === 1) {
-        props = objs[0];
+        // only one object
+        attribs = objs[0];
       } else {
+        // looks like we have multiple objects
         if (!t.isObjectExpression(objs[0])) {
           objs.unshift(t.objectExpression([]));
         }
 
-        props = t.callExpression(
+        // spread it
+        attribs = t.callExpression(
           t.memberExpression(t.identifier("React"), t.identifier("__spread")),
           objs
         );
       }
     } else {
-      props = t.literal(null);
+      attribs = t.literal(null);
     }
 
-    args.push(props);
+    args.push(attribs);
 
     if (reactCompat) {
       if (tagName && isTag(tagName)) {

lib/6to5/types/builder-keys.json

@@ -9,6 +9,7 @@
   "ExpressionStatement":     ["expression"],
   "File":                    ["program", "comments", "tokens"],
   "FunctionExpression":      ["id", "params", "body", "generator"],
+  "FunctionDeclaration":     ["id", "params", "body", "generator"],
   "Identifier":              ["name"],
   "IfStatement":             ["test", "consequent", "alternate"],
   "ImportDeclaration":       ["specifiers", "source"],

lib/6to5/types/index.js

@@ -307,6 +307,31 @@ t.toStatement = function (node, ignore) {
   return node;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @returns {Object}
+ */
+
+exports.toExpression = function (node) {
+  if (t.isExpressionStatement(node)) {
+    node = node.expression;
+  }
+
+  if (t.isClass(node)) {
+    node.type = "ClassExpression";
+  } else if (t.isFunction(node)) {
+    node.type = "FunctionExpression";
+  }
+
+  if (t.isExpression(node)) {
+    return node;
+  } else {
+    throw new Error("cannot turn " + node.type + " to an expression");
+  }
+};
+
 /**
  * Description
  *

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.10.0",
+  "version": "2.11.0",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -43,7 +43,7 @@
     "ast-types": "~0.6.1",
     "chokidar": "0.11.1",
     "commander": "2.5.0",
-    "core-js": "^0.4.1",
+    "core-js": "^0.4.4",
     "estraverse": "1.8.0",
     "esutils": "1.1.6",
     "esvalid": "^1.1.0",

test/browserify.js

@@ -12,7 +12,7 @@ suite("browserify", function() {
       assert.ok(bundle.length, "bundle output code");
 
       // ensure that the code runs without throwing an exception
-      vm.runInNewContext(bundle, {});
+      vm.runInNewContext("var global = this;\n" + bundle, {});
       done();
     })
   })

test/fixtures/transformation/es6-classes/accessing-super-class/expected.js

@@ -28,44 +28,44 @@ var _get = function get(object, property, receiver) {
   }
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
-    var _get2, _get3, _get4, _get5;
+  function Test() {
+    var _get2, _get3;
     woops["super"].test();
     _get(Object.getPrototypeOf(Test.prototype), "constructor", this).call(this);
     _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
 
-    (_get2 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get2, [this].concat(_slice.call(arguments)));
-    (_get3 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get3, [this, "test"].concat(_slice.call(arguments)));
+    _get(Object.getPrototypeOf(Test.prototype), "constructor", this).apply(this, arguments);
+    (_get2 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
 
-    (_get4 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get4, [this].concat(_slice.call(arguments)));
-    (_get5 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get5, [this, "test"].concat(_slice.call(arguments)));
-  };
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
+    (_get3 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get3, [this, "test"].concat(_slice.call(arguments)));
+  }
 
   _inherits(Test, Foo);
 
   _prototypeProperties(Test, {
     foo: {
       value: function () {
-        var _get6, _get7;
+        var _get4;
         _get(Object.getPrototypeOf(Test), "foo", this).call(this);
-        (_get6 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get6, [this].concat(_slice.call(arguments)));
-        (_get7 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get7, [this, "test"].concat(_slice.call(arguments)));
+        _get(Object.getPrototypeOf(Test), "foo", this).apply(this, arguments);
+        (_get4 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get4, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       enumerable: true,
@@ -74,10 +74,10 @@ var Test = (function (Foo) {
   }, {
     test: {
       value: function () {
-        var _get8, _get9;
+        var _get5;
         _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
-        (_get8 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get8, [this].concat(_slice.call(arguments)));
-        (_get9 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get9, [this, "test"].concat(_slice.call(arguments)));
+        _get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
+        (_get5 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get5, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       enumerable: true,

test/fixtures/transformation/es6-classes/accessing-super-properties/expected.js

@@ -22,26 +22,26 @@ var _get = function get(object, property, receiver) {
   }
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     _get(Object.getPrototypeOf(Test.prototype), "test", this);
     _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever;
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/es6-classes/calling-super-properties/expected.js

@@ -27,26 +27,26 @@ var _get = function get(object, property, receiver) {
   }
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever();
     _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
-  };
+  }
 
   _inherits(Test, Foo);
 

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

@@ -1,18 +1,18 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = function Test() {
@@ -20,9 +20,9 @@ var Test = function Test() {
 };
 
 var Foo = (function (Bar) {
-  var Foo = function Foo() {
+  function Foo() {
     this.state = "test";
-  };
+  }
 
   _inherits(Foo, Bar);
 

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var Test = (function () {
-  var Test = function Test() {};
+  function Test() {}
 
   _prototypeProperties(Test, null, {
     test: {

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var Test = (function () {
-  var Test = function Test() {};
+  function Test() {}
 
   _prototypeProperties(Test, null, {
     test: {

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var Test = (function () {
-  var Test = function Test() {};
+  function Test() {}
 
   _prototypeProperties(Test, null, {
     test: {

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var Test = (function () {
-  var Test = function Test() {};
+  function Test() {}
 
   _prototypeProperties(Test, null, {
     test: {

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var A = (function () {
-  var A = function A() {};
+  function A() {}
 
   _prototypeProperties(A, {
     a: {

test/fixtures/transformation/es6-classes/super-class-id-member-expression/expected.js

@@ -1,26 +1,26 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var BaseController = (function (_Chaplin$Controller) {
-  var BaseController = function BaseController() {
+  function BaseController() {
     if (Object.getPrototypeOf(BaseController) !== null) {
       Object.getPrototypeOf(BaseController).apply(this, arguments);
     }
-  };
+  }
 
   _inherits(BaseController, _Chaplin$Controller);
 
@@ -28,11 +28,11 @@ var BaseController = (function (_Chaplin$Controller) {
 })(Chaplin.Controller);
 
 var BaseController2 = (function (_Chaplin$Controller$Another) {
-  var BaseController2 = function BaseController2() {
+  function BaseController2() {
     if (Object.getPrototypeOf(BaseController2) !== null) {
       Object.getPrototypeOf(BaseController2).apply(this, arguments);
     }
-  };
+  }
 
   _inherits(BaseController2, _Chaplin$Controller$Another);
 

test/fixtures/transformation/es6-classes/super-class/expected.js

@@ -1,26 +1,26 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     if (Object.getPrototypeOf(Test) !== null) {
       Object.getPrototypeOf(Test).apply(this, arguments);
     }
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/es7-abstract-references/private/expected.js

@@ -7,7 +7,7 @@ var D = (function () {
   var F = new WeakMap(),
       G = new WeakMap();
   var E = new WeakMap();
-  var D = function D() {};
+  function D() {}
 
   return D;
 })();

test/fixtures/transformation/optional-classes-fast-super/accessing-super-class/expected.js

@@ -6,23 +6,23 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     var _Foo$prototype$test, _Foo$prototype$test2;
     woops["super"].test();
     Foo.call(this);
@@ -33,7 +33,7 @@ var Test = (function (Foo) {
 
     (_Foo$prototype$test = Foo.prototype.test).call.apply(_Foo$prototype$test, [this].concat(_slice.call(arguments)));
     (_Foo$prototype$test2 = Foo.prototype.test).call.apply(_Foo$prototype$test2, [this, "test"].concat(_slice.call(arguments)));
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/optional-classes-fast-super/accessing-super-properties/expected.js

@@ -1,25 +1,25 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     Foo.prototype.test;
     Foo.prototype.test.whatever;
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/optional-classes-fast-super/calling-super-properties/expected.js

@@ -5,26 +5,26 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     Foo.prototype.test.whatever();
     Foo.prototype.test.call(this);
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/optional-classes-fast-super/super-class-id-member-expression/expected.js

@@ -1,26 +1,26 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var BaseController = (function (_Chaplin$Controller) {
-  var BaseController = function BaseController() {
+  function BaseController() {
     if (Chaplin.Controller != null) {
       Chaplin.Controller.apply(this, arguments);
     }
-  };
+  }
 
   _inherits(BaseController, _Chaplin$Controller);
 
@@ -28,11 +28,11 @@ var BaseController = (function (_Chaplin$Controller) {
 })(Chaplin.Controller);
 
 var BaseController2 = (function (_Chaplin$Controller$Another) {
-  var BaseController2 = function BaseController2() {
+  function BaseController2() {
     if (Chaplin.Controller.Another != null) {
       Chaplin.Controller.Another.apply(this, arguments);
     }
-  };
+  }
 
   _inherits(BaseController2, _Chaplin$Controller$Another);
 

test/fixtures/transformation/optional-classes-fast-super/super-class/expected.js

@@ -1,26 +1,26 @@
 "use strict";
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 };
 
 var Test = (function (Foo) {
-  var Test = function Test() {
+  function Test() {
     if (Foo != null) {
       Foo.apply(this, arguments);
     }
-  };
+  }
 
   _inherits(Test, Foo);
 

test/fixtures/transformation/optional-core-aliasing/aliased-constructors/actual.js

@@ -0,0 +1,7 @@
+obj.constructor === Object;
+obj.constructor === Promise;
+
+Symbol();
+Symbol("test");
+
+new Map();

test/fixtures/transformation/optional-core-aliasing/aliased-constructors/expected.js

@@ -6,5 +6,10 @@ var _interopRequire = function (obj) {
 
 var _core = _interopRequire(require("core-js/library"));
 
-_core.Symbol("test");
+obj.constructor === Object;
+obj.constructor === _core.Promise;
+
 _core.Symbol();
+_core.Symbol("test");
+
+new _core.Map();

test/fixtures/transformation/optional-core-aliasing/ignore-natives/actual.js

@@ -1 +0,0 @@
-obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/ignore-natives/expected.js

@@ -1,9 +0,0 @@
-"use strict";
-
-var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
-};
-
-var _core = _interopRequire(require("core-js/library"));
-
-obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/map-symbol/actual.js

@@ -1,2 +0,0 @@
-Symbol("test");
-Symbol();

test/fixtures/transformation/optional-proto-to-assign/class/expected.js

@@ -10,27 +10,27 @@ var _defaults = function (obj, defaults) {
   return obj;
 };
 
-var _inherits = function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+var _inherits = function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) _defaults(child, parent);
+  if (superClass) _defaults(subClass, superClass);
 };
 
 var Foo = (function (Bar) {
-  var Foo = function Foo() {
+  function Foo() {
     if (Object.getPrototypeOf(Foo) !== null) {
       Object.getPrototypeOf(Foo).apply(this, arguments);
     }
-  };
+  }
 
   _inherits(Foo, Bar);
 

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

@@ -15,7 +15,7 @@ var _defineProperty = function (obj, key, value) {
 };
 
 var Foo = (function () {
-  var Foo = function Foo() {};
+  function Foo() {}
 
   _prototypeProperties(Foo, null, _defineProperty({
     bar: {

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

@@ -6,7 +6,7 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
 };
 
 var Test = (function () {
-  var Test = function Test() {};
+  function Test() {}
 
   _prototypeProperties(Test, null, {
     bar: {