v3.4.0

will be merged into strict formatters in next major
TODO: rewrite all module formatters as they've gotten out of han

.jshintrc

@@ -2,6 +2,7 @@
   "esnext": true,
   "indent": 2,
   "freeze": true,
+  "validthis": true,
   "camelcase": true,
   "unused": true,
   "eqnull": true,

CHANGELOG.md

@@ -11,6 +11,27 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 3.4.0
+
+ * **New Feature**
+  * Add `commonStandard` module formatter.
+ * **Bug Fix**
+  * Fix conflicting `--module-ids` shorthand arg in `$ 6to5`.
+ * **Internal**
+  * Lots of internal refactoring with scope tracking and traversal.
+ * **Polish**
+  * Don't return `map` in the API result if `sourceMap` was set to `"inline"`.
+
+## 3.3.12
+
+ * **Bug Fix**
+  * Don't override `MemberExpression`s with `core-js` in `selfContained` if a local binding exists.
+
+## 3.3.11
+
+ * **Bug Fix**
+  * Fix the require cache.
+
 ## 3.3.10
 
  * **Internal**

Makefile

@@ -92,7 +92,7 @@ publish:
 	make publish-core
 	make publish-runtime
 
-	rm -rf templates.json browser.js browser-polyfill.js
+	rm -rf templates.json browser.js browser-polyfill.js runtime.js
 
 publish-runtime:
 	cd packages; \

bin/6to5/index.js

@@ -23,7 +23,7 @@ commander.option("-L, --loose [list]", "List of transformers to enable loose mod
 commander.option("-o, --out-file [out]", "Compile all input files into a single file");
 commander.option("-d, --out-dir [out]", "Compile an input directory of modules into an output directory");
 commander.option("-c, --remove-comments", "Remove comments from the compiled code", false);
-commander.option("-m, --module-ids", "Insert module id in modules", false);
+commander.option("-i, --module-ids", "Insert module id in modules", false);
 commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
 commander.option("--keep-module-id-extensions", "Keep extensions when generating module ids", false);
 

bin/6to5/util.js

@@ -2,7 +2,7 @@ var readdir = require("fs-readdir-recursive");
 var index   = require("./index");
 var util    = require("../../lib/6to5/util");
 var path    = require("path");
-var to5     = require("../../lib/6to5");
+var to5     = require("../../lib/6to5/api/node");
 var fs      = require("fs");
 var _       = require("lodash");
 

bin/_6to5-node

@@ -4,7 +4,7 @@ var commander = require("commander");
 var Module    = require("module");
 var path      = require("path");
 var repl      = require("repl");
-var to5       = require("../lib/6to5");
+var to5       = require("../lib/6to5/api/node");
 var util      = require("../lib/6to5/util");
 var vm        = require("vm");
 var _         = require("lodash");

lib/6to5/api/browser.js

@@ -1,8 +1,8 @@
 "use strict";
 
-var transform = module.exports = require("./transformation");
+var transform = module.exports = require("../transformation");
 
-transform.version = require("../../package").version;
+transform.version = require("../../../package").version;
 
 transform.transform = transform;
 

lib/6to5/api/node.js

@@ -1,24 +1,24 @@
 "use strict";
 
-var transform  = require("./transformation");
-var util       = require("./util");
-var fs         = require("fs");
 var isFunction = require("lodash/lang/isFunction");
+var transform  = require("../transformation");
+var util       = require("../util");
+var fs         = require("fs");
 
-exports.version = require("../../package").version;
+exports.version = require("../../../package").version;
 
-exports.runtime = require("./build-runtime");
+exports.runtime = require("../build-runtime");
 
-exports.types = require("./types");
+exports.types = require("../types");
 
 exports.register = function (opts) {
-  var register = require("./register");
+  var register = require("./register/node");
   if (opts != null) register(opts);
   return register;
 };
 
 exports.polyfill = function () {
-  require("./polyfill");
+  require("../polyfill");
 };
 
 exports.canCompile = util.canCompile;

lib/6to5/api/register/browser.js

@@ -4,4 +4,4 @@
 
 module.exports = function () {};
 
-require("./polyfill");
+require("../../polyfill");

lib/6to5/api/register/cache.js

@@ -12,14 +12,6 @@ exports.save = function () {
 };
 
 exports.load = function () {
-  if (!fs.existsSync(FILENAME)) return;
-
-  try {
-    data = JSON.parse(fs.readFileSync(FILENAME));
-  } catch (err) {
-    return;
-  }
-
   process.on("exit", exports.save);
 
   var sigint = function () {
@@ -29,6 +21,14 @@ exports.load = function () {
   };
 
   process.on("SIGINT", sigint);
+
+  if (!fs.existsSync(FILENAME)) return;
+
+  try {
+    data = JSON.parse(fs.readFileSync(FILENAME));
+  } catch (err) {
+    return;
+  }
 };
 
 exports.get = function () {

lib/6to5/api/register/node.js

@@ -1,14 +1,14 @@
 "use strict";
 
-require("./polyfill");
+require("../../polyfill");
 
 var sourceMapSupport = require("source-map-support");
-var registerCache    = require("./register-cache");
-var util             = require("./util");
-var to5              = require("./index");
-var fs               = require("fs");
+var registerCache    = require("./cache");
 var extend           = require("lodash/object/extend");
 var each             = require("lodash/collection/each");
+var util             = require("../../util");
+var to5              = require("../node");
+var fs               = require("fs");
 
 sourceMapSupport.install({
   retrieveSourceMap: function (source) {

lib/6to5/build-helpers.js

@@ -1,4 +1,4 @@
-var File = require("./file");
+var File = require("./transformation/file");
 var util = require("./util");
 var each = require("lodash/collection/each");
 var t    = require("./types");

lib/6to5/detection/index.js

@@ -1,7 +1,7 @@
 module.exports = detect;
 
 var SYNTAX_KEYS = require("./syntax-keys");
-var traverse    = require("../traverse");
+var traverse    = require("../traversal");
 var visitors    = traverse.explode(require("./visitors"));
 
 function detect(ast) {

lib/6to5/generation/buffer.js

@@ -2,10 +2,10 @@
 
 module.exports = Buffer;
 
-var util      = require("../util");
-var isNumber  = require("lodash/lang/isNumber");
 var isBoolean = require("lodash/lang/isBoolean");
 var contains  = require("lodash/collection/contains");
+var isNumber  = require("lodash/lang/isNumber");
+var util      = require("../util");
 
 function Buffer(position, format) {
   this.position = position;

lib/6to5/generation/generators/jsx.js

@@ -75,6 +75,4 @@ exports.JSXClosingElement = function (node, print) {
   this.push(">");
 };
 
-exports.JSXEmptyExpression = function () {
-
-};
+exports.JSXEmptyExpression = function () {};

lib/6to5/generation/index.js

@@ -12,12 +12,12 @@ var Whitespace   = require("./whitespace");
 var SourceMap    = require("./source-map");
 var Position     = require("./position");
 var Buffer       = require("./buffer");
+var extend       = require("lodash/object/extend");
+var merge        = require("lodash/object/merge");
+var each         = require("lodash/collection/each");
 var util         = require("../util");
 var n            = require("./node");
 var t            = require("../types");
-var each         = require("lodash/collection/each");
-var extend       = require("lodash/object/extend");
-var merge        = require("lodash/object/merge");
 
 function CodeGenerator(ast, opts, code) {
   opts = opts || {};
@@ -25,6 +25,7 @@ function CodeGenerator(ast, opts, code) {
   this.comments = ast.comments || [];
   this.tokens   = ast.tokens || [];
   this.format   = CodeGenerator.normalizeOptions(code, opts);
+  this.opts     = opts;
   this.ast      = ast;
 
   this.whitespace = new Whitespace(this.tokens, this.comments);

lib/6to5/helpers/normalize-ast.js

@@ -0,0 +1,9 @@
+var t = require("../types");
+
+module.exports = function (ast, comments, tokens) {
+  if (ast && ast.type === "Program") {
+    return t.file(ast, comments || [], tokens || []);
+  } else {
+    throw new Error("Not a valid ast?");
+  }
+};

lib/6to5/helpers/parse.js

@@ -0,0 +1,49 @@
+var normalizeAst = require("./normalize-ast");
+var estraverse   = require("estraverse");
+var codeFrame    = require("./code-frame");
+var acorn        = require("acorn-6to5");
+
+module.exports = function (opts, code, callback) {
+  try {
+    var comments = [];
+    var tokens   = [];
+
+    var ast = acorn.parse(code, {
+      allowImportExportEverywhere: opts.allowImportExportEverywhere,
+      allowReturnOutsideFunction:  !opts._anal,
+      ecmaVersion:                 opts.experimental ? 7 : 6,
+      playground:                  opts.playground,
+      strictMode:                  opts.strictMode,
+      onComment:                   comments,
+      locations:                   true,
+      onToken:                     tokens,
+      ranges:                      true
+    });
+
+    estraverse.attachComments(ast, comments, tokens);
+
+    ast = normalizeAst(ast, comments, tokens);
+
+    if (callback) {
+      return callback(ast);
+    } else {
+      return ast;
+    }
+  } catch (err) {
+    if (!err._6to5) {
+      err._6to5 = true;
+      var message = opts.filename + ": " + err.message;
+
+      var loc = err.loc;
+      if (loc) {
+        var frame = codeFrame(code, loc.line, loc.column + 1);
+        message += frame;
+      }
+
+      if (err.stack) err.stack = err.stack.replace(err.message, message);
+      err.message = message;
+    }
+
+    throw err;
+  }
+};

lib/6to5/patch.js

@@ -1,7 +1,7 @@
 "use strict";
 
-var t      = require("./types");
 var extend = require("lodash/object/extend");
+var t      = require("./types");
 
 require("./types/node");
 

lib/6to5/transformation/file.js

@@ -5,16 +5,17 @@ module.exports = File;
 var SHEBANG_REGEX = /^\#\!.*/;
 
 var isFunction = require("lodash/lang/isFunction");
-var transform  = require("./transformation");
-var generate   = require("./generation");
+var transform  = require("./index");
+var generate   = require("../generation");
 var defaults   = require("lodash/object/defaults");
 var contains   = require("lodash/collection/contains");
-var clone      = require("./helpers/clone");
-var Scope      = require("./traverse/scope");
-var util       = require("./util");
+var clone      = require("../helpers/clone");
+var parse      = require("../helpers/parse");
+var Scope      = require("../traversal/scope");
+var util       = require("../util");
 var path       = require("path");
 var each       = require("lodash/collection/each");
-var t          = require("./types");
+var t          = require("../types");
 
 function File(opts) {
   this.dynamicImportIds = {};
@@ -159,8 +160,8 @@ File.prototype.normalizeOptions = function (opts) {
 
   opts.blacklist = transform._ensureTransformerNames("blacklist", opts.blacklist);
   opts.whitelist = transform._ensureTransformerNames("whitelist", opts.whitelist);
-  opts.optional = transform._ensureTransformerNames("optional", opts.optional);
-  opts.loose = transform._ensureTransformerNames("loose", opts.loose);
+  opts.optional  = transform._ensureTransformerNames("optional", opts.optional);
+  opts.loose     = transform._ensureTransformerNames("loose", opts.loose);
 
   return opts;
 };
@@ -197,6 +198,12 @@ File.prototype.buildTransformers = function () {
   this.transformers = transformers;
 };
 
+File.prototype.debug = function (msg) {
+  var parts = this.opts.filename;
+  if (msg) parts += ": " + msg;
+  util.debug(parts);
+};
+
 File.prototype.toArray = function (node, i) {
   if (t.isArrayExpression(node)) {
     return node;
@@ -334,16 +341,14 @@ File.prototype.parse = function (code) {
   opts.allowImportExportEverywhere = this.isLoose("es6.modules");
   //opts.strictMode = this.transformers.useStrict.canRun();
 
-  return util.parse(opts, code, function (tree) {
+  return parse(opts, code, function (tree) {
     self.transform(tree);
     return self.generate();
   });
 };
 
 File.prototype.transform = function (ast) {
-  var self = this;
-
-  util.debug(this.opts.filename);
+  this.debug();
 
   this.ast = ast;
   this.lastStatements = t.getLastStatements(ast.program);
@@ -356,42 +361,46 @@ File.prototype.transform = function (ast) {
 
   this.checkNode(ast);
 
-  var astRun = function (key) {
-    each(self.transformerStack, function (pass) {
-      pass.astRun(key);
-    });
-  };
-
-  astRun("enter");
+  this.call("pre");
 
   each(this.transformerStack, function (pass) {
     pass.transform();
   });
 
-  astRun("exit");
+  this.call("post");
 };
 
-var checkTransformerVisitor = {
-  enter: function (node, parent, scope, context, state) {
-    state.check(node, scope);
+File.prototype.call = function (key) {
+  var stack = this.transformerStack;
+  for (var i = 0; i < stack.length; i++) {
+    var transformer = stack[i].transformer;
+    if (transformer[key]) {
+      transformer[key](this);
+    }
   }
 };
 
+var checkTransformerVisitor = {
+  enter: function (node, parent, scope, state) {
+    checkNode(state.stack, node, scope);
+  }
+};
+
+var checkNode = function (stack, node, scope) {
+  each(stack, function (pass) {
+    if (pass.shouldRun) return;
+    pass.checkNode(node, scope);
+  });
+};
+
 File.prototype.checkNode = function (node, scope) {
-  var self = this;
+  var stack = this.transformerStack;
   scope = scope || this.scope;
 
-  var check = function (node, scope) {
-    each(self.transformerStack, function (pass) {
-      if (pass.shouldRun) return;
-      pass.checkNode(node, scope);
-    });
-  };
-
-  check(node, scope);
+  checkNode(stack, node, scope);
 
   scope.traverse(node, checkTransformerVisitor, {
-    check: check
+    stack: stack
   });
 };
 
@@ -419,6 +428,7 @@ File.prototype.generate = function () {
 
   if (opts.sourceMap === "inline") {
     result.code += "\n" + util.sourceMapToComment(result.map);
+    result.map = null;
   }
 
   return result;

lib/6to5/transformation/helpers/build-binary-assignment-operator-transformer.js

@@ -12,7 +12,7 @@ module.exports = function (exports, opts) {
     return t.assignmentExpression("=", left, right);
   };
 
-  exports.ExpressionStatement = function (node, parent, scope, context, file) {
+  exports.ExpressionStatement = function (node, parent, scope, file) {
     // hit the `AssignmentExpression` one below
     if (file.isConsequenceExpressionStatement(node)) return;
 
@@ -29,7 +29,7 @@ module.exports = function (exports, opts) {
     return nodes;
   };
 
-  exports.AssignmentExpression = function (node, parent, scope, context, file) {
+  exports.AssignmentExpression = function (node, parent, scope, file) {
     if (!isAssignment(node)) return;
 
     var nodes    = [];

lib/6to5/transformation/helpers/build-conditional-assignment-operator-transformer.js

@@ -8,7 +8,7 @@ module.exports = function (exports, opts) {
     return t.assignmentExpression("=", left, right);
   };
 
-  exports.ExpressionStatement = function (node, parent, scope, context, file) {
+  exports.ExpressionStatement = function (node, parent, scope, file) {
     // hit the `AssignmentExpression` one below
     if (file.isConsequenceExpressionStatement(node)) return;
 
@@ -27,7 +27,7 @@ module.exports = function (exports, opts) {
     return nodes;
   };
 
-  exports.AssignmentExpression = function (node, parent, scope, context, file) {
+  exports.AssignmentExpression = function (node, parent, scope, file) {
     if (!opts.is(node, file)) return;
 
     var nodes    = [];

lib/6to5/transformation/helpers/define-map.js

@@ -1,6 +1,6 @@
 var cloneDeep = require("lodash/lang/cloneDeep");
-var traverse  = require("../../traverse");
-var clone      = require("lodash/lang/clone");
+var traverse  = require("../../traversal");
+var clone     = require("lodash/lang/clone");
 var each      = require("lodash/collection/each");
 var has       = require("lodash/object/has");
 var t         = require("../../types");

lib/6to5/transformation/helpers/name-method.js

@@ -4,7 +4,7 @@ var util = require("../../util");
 var t    = require("../../types");
 
 var visitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     // check if this node is an identifier that matches the same as our function id
     if (!t.isIdentifier(node, { name: state.id })) return;
 
@@ -17,7 +17,7 @@ var visitor = {
     if (localDeclar !== state.outerDeclar) return;
 
     state.selfReference = true;
-    context.stop();
+    this.stop();
   }
 };
 

lib/6to5/transformation/helpers/remap-async-to-generator.js

@@ -3,8 +3,8 @@
 var t = require("../../types");
 
 var visitor = {
-  enter: function (node, parent, scope, context) {
-    if (t.isFunction(node)) context.skip();
+  enter: function (node) {
+    if (t.isFunction(node)) this.skip();
 
     if (t.isAwaitExpression(node)) {
       node.type = "YieldExpression";

lib/6to5/transformation/helpers/replace-supers.js

@@ -37,7 +37,12 @@ ReplaceSupers.prototype.setSuperProperty = function (property, value, isStatic,
   return t.callExpression(
     this.file.addHelper("set"),
     [
-      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
+      t.callExpression(
+        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+        [
+          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
+        ]
+      ),
       isComputed ? property : t.literal(property.name),
       value,
       thisExpression
@@ -63,7 +68,12 @@ ReplaceSupers.prototype.getSuperProperty = function (property, isStatic, isCompu
   return t.callExpression(
     this.file.addHelper("get"),
     [
-      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
+      t.callExpression(
+        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+        [
+          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
+        ]
+      ),
       isComputed ? property : t.literal(property.name),
       thisExpression
     ]
@@ -79,19 +89,19 @@ ReplaceSupers.prototype.replace = function () {
 };
 
 var visitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     var topLevel = state.topLevel;
     var self = state.self;
 
     if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
       // we need to call traverseLevel again so we're context aware
       self.traverseLevel(node, false);
-      return context.skip();
+      return this.skip();
     }
 
     if (t.isProperty(node, { method: true }) || t.isMethodDefinition(node)) {
       // break on object methods
-      return context.skip();
+      return this.skip();
     }
 
     var getThisReference = topLevel ?
@@ -212,13 +222,13 @@ ReplaceSupers.prototype.specHandle = function (getThisReference, node, parent) {
   var args;
   var thisReference;
 
-  if (t.isIdentifier(node, { name: "super" })) {
-    if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
-      throw this.file.errorWithNode(node, "illegal use of bare super");
-    }
-  } else if (t.isCallExpression(node)) {
+  if (isIllegalBareSuper(node, parent)) {
+    throw this.file.errorWithNode(node, "Illegal use of bare super");
+  }
+
+  if (t.isCallExpression(node)) {
     var callee = node.callee;
-    if (t.isIdentifier(callee, { name: "super" })) {
+    if (isSuper(callee, node)) {
       // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
       property = methodNode.key;
       computed = methodNode.computed;
@@ -231,28 +241,19 @@ ReplaceSupers.prototype.specHandle = function (getThisReference, node, parent) {
         var methodName = methodNode.key.name || "METHOD_NAME";
         throw this.file.errorWithNode(node, "Direct super call is illegal in non-constructor, use super." + methodName + "() instead");
       }
-    } else {
-      if (!t.isMemberExpression(callee)) return;
-      if (callee.object.name !== "super") return;
-
+    } else if (t.isMemberExpression(callee) && isSuper(callee.object, callee)) {
       // 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;
-
+  } else if (t.isMemberExpression(node) && isSuper(node.object, node)) {
     // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
     property = node.property;
     computed = node.computed;
-  } else if (t.isAssignmentExpression(node)) {
-    if (!t.isIdentifier(node.left.object, { name: "super" })) return;
-    if (methodNode.kind !== "set") return;
-
-    thisReference = getThisReference();
+  } else if (t.isAssignmentExpression(node) && isSuper(node.left.object, node.left) && methodNode.kind === "set") {
     // super.name = "val"; -> _set(Object.getPrototypeOf(ClassName.prototype), "name", this);
-    return this.setSuperProperty(node.left.property, node.right, methodNode.static, node.left.computed, thisReference);
+    return this.setSuperProperty(node.left.property, node.right, methodNode.static, node.left.computed, getThisReference());
   }
 
   if (!property) return;
@@ -276,3 +277,14 @@ ReplaceSupers.prototype.specHandle = function (getThisReference, node, parent) {
     return superProperty;
   }
 };
+
+var isIllegalBareSuper = function (node, parent) {
+  if (!isSuper(node, parent)) return false;
+  if (t.isMemberExpression(parent, { computed: false })) return false;
+  if (t.isCallExpression(parent, { callee: node })) return false;
+  return true;
+};
+
+var isSuper = function (node, parent) {
+  return t.isIdentifier(node, { name: "super" }) && t.isReferenced(node, parent);
+};

lib/6to5/transformation/index.js

@@ -2,11 +2,11 @@
 
 module.exports = transform;
 
-var Transformer = require("./transformer");
-var object      = require("../helpers/object");
-var File        = require("../file");
-var util        = require("../util");
-var each        = require("lodash/collection/each");
+var normalizeAst = require("../helpers/normalize-ast");
+var Transformer  = require("./transformer");
+var object       = require("../helpers/object");
+var File         = require("./file");
+var each         = require("lodash/collection/each");
 
 function transform(code, opts) {
   var file = new File(opts);
@@ -14,7 +14,7 @@ function transform(code, opts) {
 }
 
 transform.fromAst = function (ast, code, opts) {
-  ast = util.normalizeAst(ast);
+  ast = normalizeAst(ast);
 
   var file = new File(opts);
   file.addCode(code);

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

@@ -27,7 +27,7 @@ function DefaultFormatter(file) {
 }
 
 DefaultFormatter.prototype.doDefaultExportInterop = function (node) {
-  return node.default && !this.noInteropRequire && !this.hasNonDefaultExports;
+  return node.default && !this.noInteropRequireExport && !this.hasNonDefaultExports;
 };
 
 DefaultFormatter.prototype.bumpImportOccurences = function (node) {
@@ -38,7 +38,7 @@ DefaultFormatter.prototype.bumpImportOccurences = function (node) {
 };
 
 var exportsVisitor = {
-  enter: function (node, parent, scope, context, formatter) {
+  enter: function (node, parent, scope, formatter) {
     var declar = node && node.declaration;
     if (t.isExportDeclaration(node)) {
       formatter.hasLocalImports = true;
@@ -63,7 +63,7 @@ DefaultFormatter.prototype.getLocalExports = function () {
 };
 
 var importsVisitor = {
-  enter: function (node, parent, scope, context, formatter) {
+  enter: function (node, parent, scope, formatter) {
     if (t.isImportDeclaration(node)) {
       formatter.hasLocalImports = true;
       extend(formatter.localImports, t.getBindingIdentifiers(node));
@@ -77,9 +77,9 @@ DefaultFormatter.prototype.getLocalImports = function () {
 };
 
 var remapVisitor = {
-  enter: function (node, parent, scope, context, formatter) {
+  enter: function (node, parent, scope, formatter) {
     if (t.isUpdateExpression(node) && formatter.isLocalReference(node.argument, scope)) {
-      context.skip();
+      this.skip();
 
       // expand to long file assignment expression
       var assign = t.assignmentExpression(node.operator[0] + "=", node.argument, t.literal(1));
@@ -107,7 +107,7 @@ var remapVisitor = {
     }
 
     if (t.isAssignmentExpression(node) && formatter.isLocalReference(node.left, scope)) {
-      context.skip();
+      this.skip();
       return formatter.remapExportAssignment(node);
     }
   }
@@ -228,7 +228,7 @@ DefaultFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
       // export * from "foo";
       nodes.push(this.buildExportsWildcard(ref, node));
     } else {
-      if (t.isSpecifierDefault(specifier) && !this.noInteropRequire) {
+      if (t.isSpecifierDefault(specifier) && !this.noInteropRequireExport) {
         // importing a default so we need to normalize it
         ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
       } else {

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

@@ -29,9 +29,8 @@ AMDFormatter.prototype.buildDependencyLiterals = function () {
  * Wrap the entire body in a `define` wrapper.
  */
 
-AMDFormatter.prototype.transform = function (ast) {
-  var program = ast.program;
-  var body    = program.body;
+AMDFormatter.prototype.transform = function (program) {
+  var body = program.body;
 
   // build an array of module names
 
@@ -87,7 +86,7 @@ AMDFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
     this.ids[node.source.value] = ref;
   } else if (t.isImportBatchSpecifier(specifier)) {
     // import * as bar from "foo";
-  } else if (t.isSpecifierDefault(specifier) && !this.noInteropRequire) {
+  } else if (t.isSpecifierDefault(specifier) && !this.noInteropRequireImport) {
     // import foo from "foo";
     ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
   } else {

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

@@ -0,0 +1,13 @@
+"use strict";
+
+module.exports = CommonStandardFormatter;
+
+var CommonStrictFormatter = require("./common-strict");
+var util = require("../../util");
+
+function CommonStandardFormatter() {
+  this.noInteropRequireImport = true;
+  CommonStrictFormatter.apply(this, arguments);
+}
+
+util.inherits(CommonStandardFormatter, CommonStrictFormatter);

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

@@ -14,7 +14,7 @@ function CommonJSFormatter() {
 util.inherits(CommonJSFormatter, DefaultFormatter);
 
 CommonJSFormatter.prototype.init = function () {
-  if (this.hasNonDefaultExports) {
+  if (!this.noInteropRequireImport && this.hasNonDefaultExports) {
     this.file.ast.program.body.push(util.template("exports-module-declaration", true));
   }
 };
@@ -27,19 +27,23 @@ CommonJSFormatter.prototype.importSpecifier = function (specifier, node, nodes)
   // import foo from "foo";
   if (t.isSpecifierDefault(specifier)) {
     if (!contains(this.file.dynamicImported, node)) {
-      ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
+      if (this.noInteropRequireImport) {
+        ref = t.memberExpression(ref, t.identifier("default"));
+      } else {
+        ref = t.callExpression(this.file.addHelper("interop-require"), [ref]);
+      }
     }
     nodes.push(t.variableDeclaration("var", [t.variableDeclarator(variableName, ref)]));
   } else {
     if (specifier.type === "ImportBatchSpecifier") {
+
+      if (!this.noInteropRequireImport) {
+        ref = t.callExpression(this.file.addHelper("interop-require-wildcard"), [ref]);
+      }
+
       // import * as bar from "foo";
       nodes.push(t.variableDeclaration("var", [
-        t.variableDeclarator(
-          variableName,
-          t.callExpression(this.file.addHelper("interop-require-wildcard"), [
-            ref
-          ])
-        )
+        t.variableDeclarator(variableName, ref)
       ]));
     } else {
       // import { foo } from "foo";

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

@@ -1,10 +1,11 @@
 module.exports = {
-  commonStrict: require("./common-strict"),
-  amdStrict:    require("./amd-strict"),
-  umdStrict:    require("./umd-strict"),
-  common:       require("./common"),
-  system:       require("./system"),
-  ignore:       require("./ignore"),
-  amd:          require("./amd"),
-  umd:          require("./umd")
+  commonStandard: require("./common-standard"),
+  commonStrict:   require("./common-strict"),
+  amdStrict:      require("./amd-strict"),
+  umdStrict:      require("./umd-strict"),
+  common:         require("./common"),
+  system:         require("./system"),
+  ignore:         require("./ignore"),
+  amd:            require("./amd"),
+  umd:            require("./umd")
 };

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

@@ -13,7 +13,8 @@ var map              = require("lodash/collection/map");
 
 function SystemFormatter(file) {
   this.exportIdentifier = file.generateUidIdentifier("export");
-  this.noInteropRequire = true;
+  this.noInteropRequireExport = true;
+  this.noInteropRequireImport = true;
 
   DefaultFormatter.apply(this, arguments);
 }
@@ -68,7 +69,7 @@ SystemFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
 };
 
 var runnerSettersVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (node._importSource === state.source) {
       if (t.isVariableDeclaration(node)) {
         each(node.declarations, function (declar) {
@@ -81,7 +82,7 @@ var runnerSettersVisitor = {
         state.nodes.push(node);
       }
 
-      context.remove();
+      this.remove();
     }
   }
 };
@@ -103,10 +104,10 @@ SystemFormatter.prototype.buildRunnerSetters = function (block, hoistDeclarators
 };
 
 var hoistVariablesVisitor = {
-  enter: function (node, parent, scope, context, hoistDeclarators) {
+  enter: function (node, parent, scope, hoistDeclarators) {
     if (t.isFunction(node)) {
       // nothing inside is accessible
-      return context.skip();
+      return this.skip();
     }
 
     if (t.isVariableDeclaration(node)) {
@@ -148,19 +149,17 @@ var hoistVariablesVisitor = {
 };
 
 var hoistFunctionsVisitor = {
-  enter: function (node, parent, scope, context, handlerBody) {
-    if (t.isFunction(node)) context.skip();
+  enter: function (node, parent, scope, handlerBody) {
+    if (t.isFunction(node)) this.skip();
 
     if (t.isFunctionDeclaration(node) || node._blockHoist) {
       handlerBody.push(node);
-      context.remove();
+      this.remove();
     }
   }
 };
 
-SystemFormatter.prototype.transform = function (ast) {
-  var program = ast.program;
-
+SystemFormatter.prototype.transform = function (program) {
   var hoistDeclarators = [];
   var moduleName = this.getModuleName();
   var moduleNameLiteral = t.literal(moduleName);

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

@@ -13,9 +13,8 @@ function UMDFormatter() {
 
 util.inherits(UMDFormatter, AMDFormatter);
 
-UMDFormatter.prototype.transform = function (ast) {
-  var program = ast.program;
-  var body    = program.body;
+UMDFormatter.prototype.transform = function (program) {
+  var body = program.body;
 
   // build an array of module names
 

lib/6to5/transformation/transformer-pass.js

@@ -1,6 +1,5 @@
 module.exports = TransformerPass;
 
-var util     = require("../util");
 var contains = require("lodash/collection/contains");
 
 /**
@@ -15,17 +14,6 @@ function TransformerPass(file, transformer) {
   this.file        = file;
 }
 
-TransformerPass.prototype.astRun = function (key) {
-  if (!this.shouldRun) return;
-
-  var handlers = this.handlers;
-  var file = this.file;
-
-  if (handlers.ast && handlers.ast[key]) {
-    handlers.ast[key](file.ast, file);
-  }
-};
-
 TransformerPass.prototype.canRun = function () {
   var transformer = this.transformer;
 
@@ -64,31 +52,12 @@ TransformerPass.prototype.checkNode = function (node) {
   }
 };
 
-var transformVisitor = {
-  enter: function (node, parent, scope, context, state) {
-    var fns = state.handlers[node.type];
-    if (!fns) return;
-    return fns.enter(node, parent, scope, context, state.file, state.pass);
-  },
-
-  exit: function (node, parent, scope, context, state) {
-    var fns = state.handlers[node.type];
-    if (!fns) return;
-    return fns.exit(node, parent, scope, context, state.file, state.pass);
-  }
-};
-
 TransformerPass.prototype.transform = function () {
   if (!this.shouldRun) return;
 
   var file = this.file;
 
-  util.debug(file.opts.filename + ": Running transformer " + this.transformer.key);
+  file.debug("Running transformer " + this.transformer.key);
 
-  this.astRun("before");
-
-  var state = { file: file, handlers: this.handlers, pass: this };
-  file.scope.traverse(file.ast, transformVisitor, state);
-
-  this.astRun("after");
+  file.scope.traverse(file.ast, this.handlers, file);
 };

lib/6to5/transformation/transformer.js

@@ -4,8 +4,9 @@ module.exports = Transformer;
 
 var TransformerPass = require("./transformer-pass");
 var isFunction      = require("lodash/lang/isFunction");
-var traverse        = require("../traverse");
+var traverse        = require("../traversal");
 var isObject        = require("lodash/lang/isObject");
+var clone           = require("../helpers/clone");
 var each            = require("lodash/collection/each");
 
 /**
@@ -15,13 +16,23 @@ var each            = require("lodash/collection/each");
  */
 
 function Transformer(key, transformer, opts) {
-  this.manipulateOptions = transformer.manipulateOptions;
-  this.check             = transformer.check;
+  transformer = clone(transformer);
 
-  this.experimental = !!transformer.experimental;
-  this.playground   = !!transformer.playground;
-  this.secondPass   = !!transformer.secondPass;
-  this.optional     = !!transformer.optional;
+  var take = function (key) {
+    var val = transformer[key];
+    delete transformer[key];
+    return val;
+  };
+
+  this.manipulateOptions = take("manipulateOptions");
+  this.check             = take("check");
+  this.post              = take("post");
+  this.pre               = take("pre");
+
+  this.experimental = !!take("experimental");
+  this.playground   = !!take("playground");
+  this.secondPass   = !!take("secondPass");
+  this.optional     = !!take("optional");
 
   this.handlers = this.normalize(transformer);
   this.opts     = opts || {};

lib/6to5/transformation/transformers/deprecated.json

@@ -34,6 +34,8 @@
   "coreAliasing": "selfContained",
   "undefinedToVoid": "spec.undefinedToVoid",
   "undeclaredVariableCheck": "validation.undeclaredVariableCheck",
-  "specPropertyLiterals": "minification.propertyLiterals",
-  "specMemberExpressionLiterals": "minification.memberExpressionLiterals"
+  "specPropertyLiterals": "es3.propertyLiterals",
+  "specMemberExpressionLiterals": "es3.memberExpressionLiterals",
+  "minification.propertyLiterals": "es3.propertyLiterals",
+  "minification.memberExpressionLiterals": "es3.memberExpressionLiterals"
 }

lib/6to5/transformation/transformers/es6/block-scoping-tdz.js

@@ -3,7 +3,7 @@
 var t = require("../../../types");
 
 var visitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (!t.isReferencedIdentifier(node, parent)) return;
 
     var declared = state.letRefs[node.name];
@@ -36,7 +36,7 @@ exports.optional = true;
 
 exports.Loop =
 exports.Program =
-exports.BlockStatement = function (node, parent, scope, context, file) {
+exports.BlockStatement = function (node, parent, scope, file) {
   var letRefs = node._letReferences;
   if (!letRefs) return;
 

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

@@ -1,6 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
+var traverse = require("../../../traversal");
 var object   = require("../../../helpers/object");
 var util     = require("../../../util");
 var t        = require("../../../types");
@@ -43,7 +43,7 @@ exports.VariableDeclaration = function (node, parent) {
   isLet(node, parent);
 };
 
-exports.Loop = function (node, parent, scope, context, file) {
+exports.Loop = function (node, parent, scope, file) {
   var init = node.left || node.init;
   if (isLet(init, node)) {
     t.ensureBlock(node);
@@ -54,7 +54,7 @@ exports.Loop = function (node, parent, scope, context, file) {
 };
 
 exports.Program =
-exports.BlockStatement = function (block, parent, scope, context, file) {
+exports.BlockStatement = function (block, parent, scope, file) {
   if (!t.isLoop(parent)) {
     var blockScoping = new BlockScoping(false, block, parent, scope, file);
     blockScoping.run();
@@ -108,7 +108,7 @@ BlockScoping.prototype.run = function () {
   }
 };
 
-function replace(node, parent, scope, context, remaps) {
+function replace(node, parent, scope, remaps) {
   if (!t.isReferencedIdentifier(node, parent)) return;
 
   var remap = remaps[node.name];
@@ -120,7 +120,7 @@ function replace(node, parent, scope, context, remaps) {
   } else {
     // scope already has it's own binding that doesn't
     // match the one we have a stored replacement for
-    if (context) context.skip();
+    if (this) this.skip();
   }
 }
 
@@ -129,7 +129,7 @@ var replaceVisitor = {
 };
 
 function traverseReplace(node, parent, scope, remaps) {
-  replace(node, parent, scope, null, remaps);
+  replace(node, parent, scope, remaps);
   scope.traverse(node, replaceVisitor, remaps);
 }
 
@@ -225,7 +225,7 @@ BlockScoping.prototype.needsClosure = function () {
 };
 
 var letReferenceFunctionVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     // not a direct reference
     if (!t.isReferencedIdentifier(node, parent)) return;
 
@@ -241,10 +241,10 @@ var letReferenceFunctionVisitor = {
 };
 
 var letReferenceBlockVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isFunction(node)) {
       scope.traverse(node, letReferenceFunctionVisitor, state);
-      return context.skip();
+      return this.skip();
     }
   }
 };
@@ -310,7 +310,7 @@ var loopNodeTo = function (node) {
 };
 
 var loopVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     var replace;
 
     if (t.isLoop(node)) {
@@ -320,7 +320,7 @@ var loopVisitor = {
     }
 
     if (t.isFunction(node) || t.isLoop(node)) {
-      return context.skip();
+      return this.skip();
     }
 
     var loopText = loopNodeTo(node);
@@ -362,7 +362,7 @@ var loopVisitor = {
 };
 
 var loopLabelVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isLabeledStatement(node)) {
       state.innerLabels.push(node.label.name);
     }
@@ -395,7 +395,7 @@ BlockScoping.prototype.checkLoop = function () {
 };
 
 var hoistVarDeclarationsVisitor = {
-  enter: function (node, parent, scope, context, self) {
+  enter: function (node, parent, scope, self) {
     if (t.isForStatement(node)) {
       if (isVar(node.init, node)) {
         node.init = t.sequenceExpression(self.pushDeclar(node.init));
@@ -407,7 +407,7 @@ var hoistVarDeclarationsVisitor = {
     } else if (isVar(node, parent)) {
       return self.pushDeclar(node).map(t.expressionStatement);
     } else if (t.isFunction(node)) {
-      return context.skip();
+      return this.skip();
     }
   }
 };

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

@@ -8,11 +8,11 @@ var t             = require("../../../types");
 
 exports.check = t.isClass;
 
-exports.ClassDeclaration = function (node, parent, scope, context, file) {
+exports.ClassDeclaration = function (node, parent, scope, file) {
   return new Class(node, file, scope, true).run();
 };
 
-exports.ClassExpression = function (node, parent, scope, context, file) {
+exports.ClassExpression = function (node, parent, scope, file) {
   if (!node.id) {
     if (t.isProperty(parent) && parent.value === node && !parent.computed && t.isIdentifier(parent.key)) {
       // var o = { foo: class {} };

lib/6to5/transformation/transformers/es6/constants.js

@@ -7,7 +7,7 @@ exports.check = function (node) {
 };
 
 var visitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isAssignmentExpression(node) || t.isUpdateExpression(node)) {
       var ids = t.getBindingIdentifiers(node);
 
@@ -24,18 +24,18 @@ var visitor = {
         // constant so we can just ignore it
         if (id === constant) continue;
 
-        var localBinding = scope.getBinding(key);
-        if (localBinding !== constant) continue;
+        // check if there's been a local binding that shadows this constant
+        if (!scope.bindingEquals(key, constant)) continue;
 
         throw state.file.errorWithNode(id, key + " is read-only");
       }
     } else if (t.isScope(node)) {
-      context.skip();
+      this.skip();
     }
   }
 };
 
-exports.Scope = function (node, parent, scope, context, file) {
+exports.Scope = function (node, parent, scope, file) {
   scope.traverse(node, visitor, {
     constants: scope.getAllDeclarationsOfKind("const"),
     file:      file

lib/6to5/transformation/transformers/es6/destructuring.js

@@ -178,7 +178,7 @@ Destructuring.prototype.init = function (pattern, parentId) {
 };
 
 exports.ForInStatement =
-exports.ForOfStatement = function (node, parent, scope, context, file) {
+exports.ForOfStatement = function (node, parent, scope, file) {
   var declar = node.left;
   if (!t.isVariableDeclaration(declar)) return;
 
@@ -207,7 +207,7 @@ exports.ForOfStatement = function (node, parent, scope, context, file) {
   block.body = nodes.concat(block.body);
 };
 
-exports.Function = function (node, parent, scope, context, file) {
+exports.Function = function (node, parent, scope, file) {
   var nodes = [];
 
   var hasDestructuring = false;
@@ -238,7 +238,7 @@ exports.Function = function (node, parent, scope, context, file) {
   block.body = nodes.concat(block.body);
 };
 
-exports.CatchClause = function (node, parent, scope, context, file) {
+exports.CatchClause = function (node, parent, scope, file) {
   var pattern = node.param;
   if (!t.isPattern(pattern)) return;
 
@@ -258,7 +258,7 @@ exports.CatchClause = function (node, parent, scope, context, file) {
   node.body.body = nodes.concat(node.body.body);
 };
 
-exports.ExpressionStatement = function (node, parent, scope, context, file) {
+exports.ExpressionStatement = function (node, parent, scope, file) {
   var expr = node.expression;
   if (expr.type !== "AssignmentExpression") return;
   if (!t.isPattern(expr.left)) return;
@@ -282,7 +282,7 @@ exports.ExpressionStatement = function (node, parent, scope, context, file) {
   return nodes;
 };
 
-exports.AssignmentExpression = function (node, parent, scope, context, file) {
+exports.AssignmentExpression = function (node, parent, scope, file) {
   if (!t.isPattern(node.left)) return;
 
   var ref = scope.generateUidIdentifier("temp");
@@ -316,7 +316,7 @@ var variableDeclarationhasPattern = function (node) {
   return false;
 };
 
-exports.VariableDeclaration = function (node, parent, scope, context, file) {
+exports.VariableDeclaration = function (node, parent, scope, file) {
   if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
   if (!variableDeclarationhasPattern(node)) return;
 

lib/6to5/transformation/transformers/es6/for-of.js

@@ -5,11 +5,11 @@ var t    = require("../../../types");
 
 exports.check = t.isForOfStatement;
 
-exports.ForOfStatement = function (node, parent, scope, context, file) {
+exports.ForOfStatement = function (node, parent, scope, file) {
   var callback = spec;
   if (file.isLoose("es6.forOf")) callback = loose;
 
-  var build  = callback(node, parent, scope, context, file);
+  var build  = callback(node, parent, scope, file);
   var declar = build.declar;
   var loop   = build.loop;
   var block  = loop.body;
@@ -34,7 +34,7 @@ exports.ForOfStatement = function (node, parent, scope, context, file) {
   return loop;
 };
 
-var loose = function (node, parent, scope, context, file) {
+var loose = function (node, parent, scope, file) {
   var left = node.left;
   var declar, id;
 
@@ -71,7 +71,7 @@ var loose = function (node, parent, scope, context, file) {
   };
 };
 
-var spec = function (node, parent, scope, context, file) {
+var spec = function (node, parent, scope, file) {
   var left = node.left;
   var declar;
 

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

@@ -4,7 +4,7 @@ var t = require("../../../types");
 
 exports.check = require("../internal/modules").check;
 
-exports.ImportDeclaration = function (node, parent, scope, context, file) {
+exports.ImportDeclaration = function (node, parent, scope, file) {
   var nodes = [];
 
   if (node.specifiers.length) {
@@ -23,7 +23,7 @@ exports.ImportDeclaration = function (node, parent, scope, context, file) {
   return nodes;
 };
 
-exports.ExportDeclaration = function (node, parent, scope, context, file) {
+exports.ExportDeclaration = function (node, parent, scope, file) {
   var nodes = [];
   var i;
 

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

@@ -15,10 +15,10 @@ var hasDefaults = function (node) {
 };
 
 var iifeVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isReferencedIdentifier(node, parent) && state.scope.hasOwnReference(node.name)) {
       state.iife = true;
-      context.stop();
+      this.stop();
     }
   }
 };

lib/6to5/transformation/transformers/es6/properties.computed.js

@@ -6,7 +6,7 @@ exports.check = function (node) {
   return t.isProperty(node) && node.computed;
 };
 
-exports.ObjectExpression = function (node, parent, scope, context, file) {
+exports.ObjectExpression = function (node, parent, scope, file) {
   var hasComputed = false;
 
   for (var i = 0; i < node.properties.length; i++) {

lib/6to5/transformation/transformers/es6/properties.shorthand.js

@@ -8,7 +8,7 @@ exports.check = function (node) {
   return t.isProperty(node) && (node.method || node.shorthand);
 };
 
-exports.Property = function (node, parent, scope, context, file) {
+exports.Property = function (node, parent, scope, file) {
   if (node.method) {
     node.method = false;
     nameMethod.property(node, file, scope);

lib/6to5/transformation/transformers/es6/spread.js

@@ -44,7 +44,7 @@ var build = function (props, file) {
   return nodes;
 };
 
-exports.ArrayExpression = function (node, parent, scope, context, file) {
+exports.ArrayExpression = function (node, parent, scope, file) {
   var elements = node.elements;
   if (!hasSpread(elements)) return;
 
@@ -59,7 +59,7 @@ exports.ArrayExpression = function (node, parent, scope, context, file) {
   return t.callExpression(t.memberExpression(first, t.identifier("concat")), nodes);
 };
 
-exports.CallExpression = function (node, parent, scope, context, file) {
+exports.CallExpression = function (node, parent, scope, file) {
   var args = node.arguments;
   if (!hasSpread(args)) return;
 
@@ -99,7 +99,7 @@ exports.CallExpression = function (node, parent, scope, context, file) {
   node.arguments.unshift(contextLiteral);
 };
 
-exports.NewExpression = function (node, parent, scope, context, file) {
+exports.NewExpression = function (node, parent, scope, file) {
   var args = node.arguments;
   if (!hasSpread(args)) return;
 

lib/6to5/transformation/transformers/es6/template-literals.js

@@ -10,7 +10,7 @@ exports.check = function (node) {
   return t.isTemplateLiteral(node) || t.isTaggedTemplateExpression(node);
 };
 
-exports.TaggedTemplateExpression = function (node, parent, scope, context, file) {
+exports.TaggedTemplateExpression = function (node, parent, scope, file) {
   var args = [];
   var quasi = node.quasi;
 

lib/6to5/transformation/transformers/es7/abstract-references.js

@@ -23,7 +23,7 @@ var container = function (parent, call, ret, file) {
   }
 };
 
-exports.AssignmentExpression = function (node, parent, scope, context, file) {
+exports.AssignmentExpression = function (node, parent, scope, file) {
   var left = node.left;
   if (!t.isVirtualPropertyExpression(left)) return;
 
@@ -63,7 +63,7 @@ exports.AssignmentExpression = function (node, parent, scope, context, file) {
   return container(parent, call, value, file);
 };
 
-exports.UnaryExpression = function (node, parent, scope, context, file) {
+exports.UnaryExpression = function (node, parent, scope, file) {
   var arg = node.argument;
   if (!t.isVirtualPropertyExpression(arg)) return;
   if (node.operator !== "delete") return;

lib/6to5/transformation/transformers/es7/comprehensions.js

@@ -1,13 +1,13 @@
 "use strict";
 
 var buildComprehension = require("../../helpers/build-comprehension");
-var traverse           = require("../../../traverse");
+var traverse           = require("../../../traversal");
 var util               = require("../../../util");
 var t                  = require("../../../types");
 
 exports.experimental = true;
 
-exports.ComprehensionExpression = function (node, parent, scope, context, file) {
+exports.ComprehensionExpression = function (node, parent, scope, file) {
   var callback = array;
   if (node.generator) callback = generator;
   return callback(node, parent, scope, file);

lib/6to5/transformation/transformers/es7/object-rest-spread.js

@@ -19,7 +19,7 @@ var hasSpread = function (node) {
   return false;
 };
 
-exports.ObjectExpression = function (node, parent, scope, context, file) {
+exports.ObjectExpression = function (node, parent, scope, file) {
   if (!hasSpread(node)) return;
 
   var args = [];

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

@@ -79,8 +79,8 @@ module.exports = {
   "spec.typeofSymbol":                     require("./spec/typeof-symbol"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
 
-  "minification.propertyLiterals":         require("./minification/property-literals"),
-  "minification.memberExpressionLiterals": require("./minification/member-expression-literals"),
+  "es3.propertyLiterals":                  require("./es3/property-literals"),
+  "es3.memberExpressionLiterals":          require("./es3/member-expression-literals"),
 
   "minification.removeDebugger":           require("./minification/remove-debugger"),
   "minification.removeConsoleCalls":       require("./minification/remove-console-calls"),

lib/6to5/transformation/transformers/internal/alias-functions.js

@@ -3,12 +3,12 @@
 var t = require("../../../types");
 
 var functionChildrenVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isFunction(node) && !node._aliasFunction) {
-      return context.skip();
+      return this.skip();
     }
 
-    if (node._ignoreAliasFunctions) return context.skip();
+    if (node._ignoreAliasFunctions) return this.skip();
 
     var getId;
 
@@ -25,11 +25,11 @@ var functionChildrenVisitor = {
 };
 
 var functionVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (!node._aliasFunction) {
       if (t.isFunction(node)) {
         // stop traversal of this node as it'll be hit again by this transformer
-        return context.skip();
+        return this.skip();
       } else {
         return;
       }
@@ -38,7 +38,7 @@ var functionVisitor = {
     // traverse all child nodes of this function and find `arguments` and `this`
     scope.traverse(node, functionChildrenVisitor, state);
 
-    return context.skip();
+    return this.skip();
   }
 };
 

lib/6to5/transformation/transformers/internal/module-formatter.js

@@ -2,16 +2,16 @@
 
 var useStrict = require("../../helpers/use-strict");
 
-exports.ast = {
-  exit: function (ast, file) {
-    if (!file.transformers["es6.modules"].canRun()) return;
+exports.post = function (file) {
+  if (!file.transformers["es6.modules"].canRun()) return;
 
-    useStrict.wrap(ast.program, function () {
-      ast.program.body = file.dynamicImports.concat(ast.program.body);
-    });
+  var program = file.ast.program;
 
-    if (file.moduleFormatter.transform) {
-      file.moduleFormatter.transform(ast);
-    }
+  useStrict.wrap(program, function () {
+    program.body = file.dynamicImports.concat(program.body);
+  });
+
+  if (file.moduleFormatter.transform) {
+    file.moduleFormatter.transform(program);
   }
 };

lib/6to5/transformation/transformers/internal/modules.js

@@ -8,7 +8,7 @@
 
 var t = require("../../../types");
 
-var resolveModuleSource = function (node, parent, scope, context, file) {
+var resolveModuleSource = function (node, parent, scope, file) {
   var resolveModuleSource = file.opts.resolveModuleSource;
   if (node.source && resolveModuleSource) {
     node.source.value = resolveModuleSource(node.source.value);

lib/6to5/transformation/transformers/minification/dead-code-elimination.js

@@ -2,7 +2,7 @@ var t = require("../../../types");
 
 exports.optional = true;
 
-exports.ExpressionStatement = function (node, parent, scope, context) {
+exports.ExpressionStatement = function (node) {
   // remove consequenceless expressions such as local variables and literals
   //
   //   var foo = true; foo; -> var foo = true;
@@ -11,12 +11,12 @@ exports.ExpressionStatement = function (node, parent, scope, context) {
 
   var expr = node.expression;
   if (t.isLiteral(expr) || (t.isIdentifier(node) && t.hasBinding(node.name))) {
-    context.remove();
+    this.remove();
   }
 };
 
 exports.IfStatement = {
-  exit: function (node, parent, scope, context) {
+  exit: function (node) {
     // todo: in scenarios where we can just return the consequent or
     // alternate we should drop the block statement if it contains no
     // block scoped variables
@@ -25,7 +25,7 @@ exports.IfStatement = {
     var alternate  = node.alternate;
     var test       = node.test;
 
-    // we can check if a test will be truthy 100% and if so we can inline
+    // we can check if a test will be truthy 100% and if so then we can inline
     // the consequent and completely ignore the alternate
     //
     //   if (true) { foo; } -> { foo; }
@@ -36,8 +36,8 @@ exports.IfStatement = {
       return alternate;
     }
 
-    // we can check if a test will be falsy 100% and if so we can inline
-    // the alternate if there is one and completely remove the consequent
+    // we can check if a test will be falsy 100% and if so we can inline the
+    // alternate if there is one and completely remove the consequent
     //
     //   if ("") { bar; } else { foo; } -> { foo; }
     //   if ("") { bar; } ->
@@ -47,7 +47,7 @@ exports.IfStatement = {
       if (alternate) {
         return alternate;
       } else {
-        return context.remove();
+        return this.remove();
       }
     }
 
@@ -60,11 +60,10 @@ exports.IfStatement = {
       alternate = node.alternate = null;
     }
 
-    // turn alternate blocks into a consequent and flip the test if the
-    // consequent block is empty
+    // if the consequent block is empty turn alternate blocks into a consequent
+    // and flip the test
     //
-    //   if (foo) {} else { bar; }
-    //   if (!foo) { bar; }
+    //   if (foo) {} else { bar; } -> if (!foo) { bar; }
     //
 
     if (t.blockStatement(consequent) && !consequent.body.length &&

lib/6to5/transformation/transformers/minification/remove-console-calls.js

@@ -6,8 +6,8 @@ var isConsole = t.buildMatchMemberExpression("console", true);
 
 exports.optional = true;
 
-exports.CallExpression = function (node, parent, scope, context) {
+exports.CallExpression = function (node) {
   if (isConsole(node.callee)) {
-    context.remove();
+    this.remove();
   }
 };

lib/6to5/transformation/transformers/minification/remove-debugger.js

@@ -2,8 +2,8 @@ var t = require("../../../types");
 
 exports.optional = true;
 
-exports.ExpressionStatement = function (node, parent, scope, context) {
+exports.ExpressionStatement = function (node) {
   if (t.isIdentifier(node.expression, { name: "debugger" })) {
-    context.remove();
+    this.remove();
   }
 };

lib/6to5/transformation/transformers/minification/rename-local-variables.js

@@ -5,6 +5,7 @@ exports.optional = true;
 exports.Scope = function () {
   // todo: get all binding identifiers, generate compact names
   // that wont collide and then call the remap identifier helper
+
   // this transformer **has** to be ran last as it will absolutley
   // destroy the scope tree
 };

lib/6to5/transformation/transformers/other/async-to-generator.js

@@ -7,7 +7,7 @@ exports.optional = true;
 
 exports.manipulateOptions = bluebirdCoroutines.manipulateOptions;
 
-exports.Function = function (node, parent, scope, context, file) {
+exports.Function = function (node, parent, scope, file) {
   if (!node.async || node.generator) return;
 
   return remapAsyncToGenerator(node, file.addHelper("async-to-generator"), scope);

lib/6to5/transformation/transformers/other/bluebird-coroutines.js

@@ -10,7 +10,7 @@ exports.manipulateOptions = function (opts) {
 
 exports.optional = true;
 
-exports.Function = function (node, parent, scope, context, file) {
+exports.Function = function (node, parent, scope, file) {
   if (!node.async || node.generator) return;
 
   return remapAsyncToGenerator(

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

@@ -26,7 +26,7 @@ exports.JSXIdentifier = function (node, parent) {
   }
 };
 
-exports.JSXNamespacedName = function (node, parent, scope, context, file) {
+exports.JSXNamespacedName = function (node, parent, scope, file) {
   throw file.errorWithNode(node, "Namespace tags are not supported. ReactJSX is not XML.");
 };
 
@@ -53,7 +53,7 @@ var isCompatTag = function (tagName) {
 };
 
 exports.JSXOpeningElement = {
-  exit: function (node, parent, scope, context, file) {
+  exit: function (node, parent, scope, file) {
     var reactCompat = file.opts.reactCompat;
     var tagExpr = node.name;
     var args = [];
@@ -259,7 +259,7 @@ var addDisplayName = function (id, call) {
   }
 };
 
-exports.ExportDeclaration = function (node, parent, scope, context, file) {
+exports.ExportDeclaration = function (node, parent, scope, file) {
   if (node.default && react.isCreateClass(node.declaration)) {
     addDisplayName(file.opts.basename, node.declaration);
   }

lib/6to5/transformation/transformers/other/regenerator.js

@@ -7,10 +7,9 @@ exports.check = function (node) {
   return t.isFunction(node) && (node.async || node.generator);
 };
 
-exports.ast = {
-  before: function (ast, file) {
-    regenerator.transform(ast, {
-      includeRuntime: file.opts.includeRegenerator && "if used"
-    });
+exports.Program = {
+  enter: function (ast) {
+    regenerator.transform(ast);
+    this.stop();
   }
 };

lib/6to5/transformation/transformers/other/self-contained.js

@@ -20,7 +20,7 @@ var ALIASABLE_CONSTRUCTORS = [
 ];
 
 var astVisitor = {
-  enter: function (node, parent, scope, context, file) {
+  enter: function (node, parent, scope, file) {
     var prop;
 
     if (t.isMemberExpression(node) && t.isReferenced(node, parent)) {
@@ -30,8 +30,8 @@ var astVisitor = {
 
       if (!t.isReferenced(obj, node)) return;
 
-      if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name)) {
-        context.skip();
+      if (!node.computed && coreHas(obj) && has(core[obj.name], prop.name) && !scope.getBinding(obj.name)) {
+        this.skip();
         return t.prependToMemberExpression(node, file.get("coreIdentifier"));
       }
     } else if (t.isReferencedIdentifier(node, parent) && !t.isMemberExpression(parent) && contains(ALIASABLE_CONSTRUCTORS, node.name) && !scope.getBinding(node.name)) {
@@ -60,27 +60,29 @@ var astVisitor = {
 
 exports.optional = true;
 
-exports.ast = {
-  enter: function (ast, file) {
-    file.setDynamic("runtimeIdentifier", function () {
-      return file.addImport("6to5-runtime/helpers", "to5Helpers");
-    });
-
-    file.setDynamic("coreIdentifier", function () {
-      return file.addImport("6to5-runtime/core-js", "core");
-    });
-
-    file.setDynamic("regeneratorIdentifier", function () {
-      return file.addImport("6to5-runtime/regenerator", "regeneratorRuntime");
-    });
-  },
-
-  after: function (ast, file) {
-    file.scope.traverse(ast, astVisitor, file);
-  }
+exports.manipulateOptions = function (opts) {
+  if (opts.whitelist.length) opts.whitelist.push("es6.modules");
 };
 
-exports.Identifier = function (node, parent, scope, context, file) {
+exports.post = function (file) {
+  file.scope.traverse(file.ast, astVisitor, file);
+};
+
+exports.pre = function (file) {
+  file.setDynamic("runtimeIdentifier", function () {
+    return file.addImport("6to5-runtime/helpers", "to5Helpers");
+  });
+
+  file.setDynamic("coreIdentifier", function () {
+    return file.addImport("6to5-runtime/core-js", "core");
+  });
+
+  file.setDynamic("regeneratorIdentifier", function () {
+    return file.addImport("6to5-runtime/regenerator", "regeneratorRuntime");
+  });
+};
+
+exports.Identifier = function (node, parent, scope, file) {
   if (node.name === "regeneratorRuntime" && t.isReferenced(node, parent)) {
     return file.get("regeneratorIdentifier");
   }

lib/6to5/transformation/transformers/other/use-strict.js

@@ -3,17 +3,16 @@
 var useStrict = require("../../helpers/use-strict");
 var t         = require("../../../types");
 
-exports.ast = {
-  exit: function (ast) {
-    if (!useStrict.has(ast.program)) {
-      ast.program.body.unshift(t.expressionStatement(t.literal("use strict")));
-    }
+exports.post = function (file) {
+  var program = file.ast.program;
+  if (!useStrict.has(program)) {
+    program.body.unshift(t.expressionStatement(t.literal("use strict")));
   }
 };
 
 exports.FunctionDeclaration =
-exports.FunctionExpression = function (node, parent, scope, context) {
-  context.skip();
+exports.FunctionExpression = function () {
+  this.skip();
 };
 
 exports.ThisExpression = function () {

lib/6to5/transformation/transformers/playground/method-binding.js

@@ -26,7 +26,7 @@ exports.BindMemberExpression = function (node, parent, scope) {
   }
 };
 
-exports.BindFunctionExpression = function (node, parent, scope, context, file) {
+exports.BindFunctionExpression = function (node, parent, scope, file) {
   var buildCall = function (args) {
     var param = scope.generateUidIdentifier("val");
     return t.functionExpression(null, [param], t.blockStatement([

lib/6to5/transformation/transformers/playground/object-getter-memoization.js

@@ -5,8 +5,8 @@ var t = require("../../../types");
 exports.playground = true;
 
 var visitor = {
-  enter: function (node, parent, scope, context, state) {
-    if (t.isFunction(node)) return;
+  enter: function (node, parent, scope, state) {
+    if (t.isFunction(node)) return this.skip();
 
     if (t.isReturnStatement(node) && node.argument) {
       node.argument = t.memberExpression(t.callExpression(state.file.addHelper("define-property"), [
@@ -19,10 +19,9 @@ var visitor = {
 };
 
 exports.Property =
-exports.MethodDefinition = function (node, parent, scope, context, file) {
+exports.MethodDefinition = function (node, parent, scope, file) {
   if (node.kind !== "memo") return;
   node.kind = "get";
-  file.checkNode(node, scope);
 
   var value = node.value;
   t.ensureBlock(value);
@@ -39,4 +38,6 @@ exports.MethodDefinition = function (node, parent, scope, context, file) {
   };
 
   scope.traverse(value, visitor, state);
+
+  return node;
 };

lib/6to5/transformation/transformers/spec/proto-to-assign.js

@@ -19,7 +19,7 @@ var buildDefaultsCallExpression = function (expr, ref, file) {
 exports.optional = true;
 exports.secondPass = true;
 
-exports.AssignmentExpression = function (node, parent, scope, context, file) {
+exports.AssignmentExpression = function (node, parent, scope, file) {
   if (!isProtoAssignmentExpression(node)) return;
 
   var nodes = [];
@@ -33,7 +33,7 @@ exports.AssignmentExpression = function (node, parent, scope, context, file) {
   return t.toSequenceExpression(nodes);
 };
 
-exports.ExpressionStatement = function (node, parent, scope, context, file) {
+exports.ExpressionStatement = function (node, parent, scope, file) {
   var expr = node.expression;
   if (!t.isAssignmentExpression(expr, { operator: "=" })) return;
 
@@ -42,7 +42,7 @@ exports.ExpressionStatement = function (node, parent, scope, context, file) {
   }
 };
 
-exports.ObjectExpression = function (node, parent, scope, context, file) {
+exports.ObjectExpression = function (node, parent, scope, file) {
   var proto;
 
   for (var i = 0; i < node.properties.length; i++) {

lib/6to5/transformation/transformers/spec/typeof-symbol.js

@@ -4,8 +4,8 @@ var t = require("../../../types");
 
 exports.optional = true;
 
-exports.UnaryExpression = function (node, parent, scope, context, file) {
-  context.skip();
+exports.UnaryExpression = function (node, parent, scope, file) {
+  this.skip();
 
   if (node.operator === "typeof") {
     var call = t.callExpression(file.addHelper("typeof"), [node.argument]);

lib/6to5/transformation/transformers/validation/no-for-in-of-assignment.js

@@ -3,7 +3,7 @@
 var t = require("../../../types");
 
 exports.ForInStatement =
-exports.ForOfStatement = function (node, parent, scope, context, file) {
+exports.ForOfStatement = function (node, parent, scope, file) {
   var left = node.left;
   if (t.isVariableDeclaration(left)) {
     var declar = left.declarations[0];

lib/6to5/transformation/transformers/validation/setters.js

@@ -1,7 +1,7 @@
 "use strict";
 
 exports.MethodDefinition =
-exports.Property = function (node, parent, scope, context, file) {
+exports.Property = function (node, parent, scope, file) {
   if (node.kind === "set" && node.value.params.length !== 1) {
     throw file.errorWithNode(node.value, "Setters must have only one parameter");
   }

lib/6to5/transformation/transformers/validation/undeclared-variable-check.js

@@ -5,7 +5,7 @@ var t           = require("../../../types");
 
 exports.optional = true;
 
-exports.Identifier = function (node, parent, scope, context, file) {
+exports.Identifier = function (node, parent, scope, file) {
   if (!t.isReferenced(node, parent)) return;
   if (scope.hasBinding(node.name)) return;
 

lib/6to5/traversal/context.js

@@ -0,0 +1,78 @@
+"use strict";
+
+/* jshint maxparams:7 */
+
+module.exports = TraversalContext;
+
+var TraversalPath = require("./path");
+var flatten       = require("lodash/array/flatten");
+var compact       = require("lodash/array/compact");
+
+function TraversalContext(scope, opts, state) {
+  this.shouldFlatten = false;
+
+  this.scope = scope;
+  this.state = state;
+  this.opts  = opts;
+
+  this.reset();
+}
+
+TraversalContext.prototype.flatten = function () {
+  this.shouldFlatten = true;
+};
+
+TraversalContext.prototype.remove = function () {
+  this.shouldRemove = true;
+  this.shouldSkip   = true;
+};
+
+TraversalContext.prototype.skip = function () {
+  this.shouldSkip = true;
+};
+
+TraversalContext.prototype.stop = function () {
+  this.shouldStop = true;
+  this.shouldSkip = true;
+};
+
+TraversalContext.prototype.reset = function () {
+  this.shouldRemove = false;
+  this.shouldSkip   = false;
+  this.shouldStop   = false;
+};
+
+TraversalContext.prototype.visitNode = function (node, obj, key) {
+  this.reset();
+  var iteration = new TraversalPath(this, node, obj, key);
+  return iteration.visit();
+};
+
+TraversalContext.prototype.visit = function (node, key) {
+  var nodes = node[key];
+  if (!nodes) return;
+
+  if (!Array.isArray(nodes)) {
+    return this.visitNode(node, node, key);
+  }
+
+  // nothing to traverse!
+  if (nodes.length === 0) {
+    return;
+  }
+
+  for (var i = 0; i < nodes.length; i++) {
+    if (nodes[i] && this.visitNode(node, nodes, i)) {
+      return true;
+    }
+  }
+
+  if (this.shouldFlatten) {
+    node[key] = flatten(node[key]);
+
+    if (key === "body") {
+      // we can safely compact this
+      node[key] = compact(node[key]);
+    }
+  }
+};

lib/6to5/traversal/index.js

@@ -0,0 +1,121 @@
+"use strict";
+
+module.exports = traverse;
+
+var TraversalContext = require("./context");
+var contains         = require("lodash/collection/contains");
+var t                = require("../types");
+
+function traverse(parent, opts, scope, state) {
+  if (!parent) return;
+
+  if (!opts.noScope && !scope) {
+    if (parent.type !== "Program" && parent.type !== "File") {
+      throw new Error("Must pass a scope unless traversing a Program/File got a " + parent.type + " node");
+    }
+  }
+
+  if (!opts) opts = {};
+  if (!opts.enter) opts.enter = function () { };
+  if (!opts.exit) opts.exit = function () { };
+
+  // array of nodes
+  if (Array.isArray(parent)) {
+    for (var i = 0; i < parent.length; i++) {
+      traverse.node(parent[i], opts, scope, state);
+    }
+  } else {
+    traverse.node(parent, opts, scope, state);
+  }
+}
+
+traverse.node = function (node, opts, scope, state) {
+  var keys = t.VISITOR_KEYS[node.type];
+  if (!keys) return;
+
+  var context = new TraversalContext(scope, opts, state);
+  for (var i = 0; i < keys.length; i++) {
+    if (context.visit(node, keys[i])) {
+      return;
+    }
+  }
+};
+
+function clearNode(node) {
+  node._declarations = null;
+  node.extendedRange = null;
+  node._scopeInfo = null;
+  node.tokens = null;
+  node.range = null;
+  node.start = null;
+  node.end = null;
+  node.loc = null;
+  node.raw = null;
+
+  if (Array.isArray(node.trailingComments)) {
+    clearComments(node.trailingComments);
+  }
+
+  if (Array.isArray(node.leadingComments)) {
+    clearComments(node.leadingComments);
+  }
+}
+
+var clearVisitor = {
+  noScope: true,
+  enter: clearNode
+};
+
+function clearComments(comments) {
+  for (var i = 0; i < comments.length; i++) {
+    clearNode(comments[i]);
+  }
+}
+
+traverse.removeProperties = function (tree) {
+  clearNode(tree);
+  traverse(tree, clearVisitor);
+
+  return tree;
+};
+
+traverse.explode = function (obj) {
+  for (var type in obj) {
+    var fns = obj[type];
+
+    var aliases = t.FLIPPED_ALIAS_KEYS[type];
+    if (aliases) {
+      for (var i = 0; i < aliases.length; i++) {
+        obj[aliases[i]] = fns;
+      }
+    }
+  }
+  return obj;
+};
+
+function hasBlacklistedType(node, parent, scope, state) {
+  if (node.type === state.type) {
+    state.has = true;
+    this.skip();
+  }
+}
+
+traverse.hasType = function (tree, scope, type, blacklistTypes) {
+  // the node we're searching in is blacklisted
+  if (contains(blacklistTypes, tree.type)) return false;
+
+  // the type we're looking for is the same as the passed node
+  if (tree.type === type) return true;
+
+  var state = {
+    has:  false,
+    type: type
+  };
+
+  traverse(tree, {
+    blacklist: blacklistTypes,
+    enter: hasBlacklistedType
+  }, scope, state);
+
+  return state.has;
+};

lib/6to5/traversal/path.js

@@ -0,0 +1,155 @@
+"use strict";
+
+module.exports = TraversalPath;
+
+/* jshint maxparams:7 */
+
+var traverse = require("./index");
+var contains = require("lodash/collection/contains");
+var Scope    = require("./scope");
+var t        = require("../types");
+
+function TraversalPath(context, parent, obj, key) {
+  this.shouldRemove = false;
+  this.shouldSkip   = false;
+  this.shouldStop   = false;
+
+  this.context = context;
+  this.state   = this.context.state;
+  this.opts    = this.context.opts;
+
+  this.key     = key;
+  this.obj     = obj;
+
+  this.parent  = parent;
+  this.scope   = TraversalPath.getScope(this.getNode(), parent, context.scope);
+  this.state   = context.state;
+}
+
+TraversalPath.prototype.remove = function () {
+  this.shouldRemove = true;
+  this.shouldSkip   = true;
+};
+
+TraversalPath.prototype.skip = function () {
+  this.shouldSkip = true;
+};
+
+TraversalPath.prototype.stop = function () {
+  this.shouldStop = true;
+  this.shouldSkip = true;
+};
+
+TraversalPath.prototype.flatten = function () {
+  this.context.flatten();
+};
+
+TraversalPath.getScope = function (node, parent, scope) {
+  var ourScope = scope;
+
+  // we're entering a new scope so let's construct it!
+  if (t.isScope(node)) {
+    ourScope = new Scope(node, parent, scope);
+  }
+
+  return ourScope;
+};
+
+TraversalPath.prototype.maybeRemove = function () {
+  if (this.shouldRemove) {
+    this.setNode(null);
+    this.flatten();
+  }
+};
+
+TraversalPath.prototype.setNode = function (val) {
+  return this.obj[this.key] = val;
+};
+
+TraversalPath.prototype.getNode = function () {
+  return this.obj[this.key];
+};
+
+TraversalPath.prototype.replaceNode = function (replacement, scope) {
+  var isArray = Array.isArray(replacement);
+
+  // inherit comments from original node to the first replacement node
+  var inheritTo = replacement;
+  if (isArray) inheritTo = replacement[0];
+  if (inheritTo) t.inheritsComments(inheritTo, this.getNode());
+
+  // replace the node
+  this.setNode(replacement);
+
+  var file = this.scope && this.scope.file;
+  if (file) {
+    if (isArray) {
+      for (var i = 0; i < replacement.length; i++) {
+        file.checkNode(replacement[i], scope);
+      }
+    } else {
+      file.checkNode(replacement, scope);
+    }
+  }
+
+  // we're replacing a statement or block node with an array of statements so we better
+  // ensure that it's a block
+  if (isArray) {
+    if (contains(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.obj)) {
+      t.ensureBlock(this.obj, this.key);
+    }
+
+    this.flatten();
+  }
+};
+
+TraversalPath.prototype.call = function (key) {
+  var node = this.getNode();
+  if (!node) return;
+
+  var opts = this.opts;
+  var fn   = opts[key];
+  if (opts[node.type]) fn = opts[node.type][key] || fn;
+
+  var replacement = fn.call(this, node, this.parent, this.scope, this.state);
+
+  if (replacement) {
+    this.replaceNode(replacement);
+    node = replacement;
+  }
+
+  this.maybeRemove();
+
+  return node;
+};
+
+TraversalPath.prototype.visit = function () {
+  var opts = this.opts;
+  var node = this.getNode();
+
+  // type is blacklisted
+  if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) {
+    return;
+  }
+
+  this.call("enter");
+
+  if (this.shouldSkip) {
+    return this.shouldStop;
+  }
+
+  node = this.getNode();
+
+  if (Array.isArray(node)) {
+    // traverse over these replacement nodes we purposely don't call exitNode
+    // as the original node has been destroyed
+    for (var i = 0; i < node.length; i++) {
+      traverse.node(node[i], opts, this.scope, this.state);
+    }
+  } else {
+    traverse.node(node, opts, this.scope, this.state);
+    this.call("exit");
+  }
+
+  return this.shouldStop;
+};

lib/6to5/traversal/scope.js

@@ -148,16 +148,15 @@ Scope.prototype.inferType = function (node) {
   }
 
   if (t.isLiteral(target) || t.isArrayExpression(target) || t.isObjectExpression(target)) {
-    // todo: possibly call some helper that will resolve these to a type annotation
+    // todo: possibly call some helper that will resolve these to a flow type annotation
   }
 
   if (t.isCallExpression(target)) {
-    // todo: need to resolve this to a return type
+    // todo: resolve this to a return type
   }
 
   if (t.isMemberExpression(target)) {
-    // todo: crawl this and find the correct type, bail on anything that we cannot
-    // possibly be 100% confident on
+    // todo: crawl this and find the correct type, bail on anything that we cannot possibly be 100% confident on
   }
 
   if (t.isIdentifier(target)) {
@@ -214,7 +213,7 @@ Scope.prototype.registerVariableDeclaration = function (declar) {
 };
 
 var functionVariableVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isFor(node)) {
       each(t.FOR_INIT_KEYS, function (key) {
         var declar = node[key];
@@ -224,7 +223,7 @@ var functionVariableVisitor = {
 
     // this block is a function so we'll stop since none of the variables
     // declared within are accessible
-    if (t.isFunction(node)) return context.skip();
+    if (t.isFunction(node)) return this.skip();
 
     // function identifier doesn't belong to this scope
     if (state.blockId && node === state.blockId) return;
@@ -241,7 +240,7 @@ var functionVariableVisitor = {
 };
 
 var programReferenceVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isReferencedIdentifier(node, parent) && !scope.hasReference(node.name)) {
       state.register(node, true);
     }
@@ -249,11 +248,11 @@ var programReferenceVisitor = {
 };
 
 var blockVariableVisitor = {
-  enter: function (node, parent, scope, context, state) {
+  enter: function (node, parent, scope, state) {
     if (t.isBlockScoped(node)) {
       state.register(node);
     } else if (t.isScope(node)) {
-      context.skip();
+      this.skip();
     }
   }
 };
@@ -287,9 +286,11 @@ Scope.prototype.crawl = function () {
 
   //
 
-  if (parent && t.isBlockStatement(block) && t.isLoop(parent.block, { body: block })) {
-    // delegate let bindings to the parent loop
-    return;
+  if (parent && t.isBlockStatement(block)) {
+    if (t.isLoop(parent.block, { body: block }) ||
+        t.isFunction(parent.block, { body: block })) {
+      return;
+    }
   }
 
   // ForStatement - left, init
@@ -305,9 +306,25 @@ Scope.prototype.crawl = function () {
     }
   }
 
-  // Program, BlockStatement - let variables
+  // FunctionExpression - id
 
-  if (t.isBlockStatement(block) || t.isProgram(block)) {
+  if (t.isFunctionExpression(block) && block.id) {
+    if (!t.isProperty(this.parentBlock, { method: true })) {
+      this.register(block.id);
+    }
+  }
+
+  // Function - params, rest
+
+  if (t.isFunction(block)) {
+    for (i = 0; i < block.params.length; i++) {
+      this.register(block.params[i]);
+    }
+  }
+
+  // Program, BlockStatement, Function - let variables
+
+  if (t.isBlockStatement(block) || t.isProgram(block) || t.isFunction(block)) {
     this.traverse(block, blockVariableVisitor, this);
   }
 
@@ -323,14 +340,6 @@ Scope.prototype.crawl = function () {
     this.register(block);
   }
 
-  // Function - params, rest
-
-  if (t.isFunction(block)) {
-    for (i = 0; i < block.params.length; i++) {
-      this.register(block.params[i]);
-    }
-  }
-
   // Program, Function - var variables
 
   if (t.isProgram(block) || t.isFunction(block)) {
@@ -340,14 +349,6 @@ Scope.prototype.crawl = function () {
     });
   }
 
-  if (t.isFunctionExpression(block) && block.id) {
-    if (!t.isProperty(this.parentBlock, { method: true })) {
-      // SpiderMonkey AST doesn't use MethodDefinition here when it probably
-      // should since they should be semantically the same?
-      this.register(block.id);
-    }
-  }
-
   // Program
 
   if (t.isProgram(block)) {
@@ -403,7 +404,7 @@ Scope.prototype.addDeclarationToFunctionScope = function (kind, node) {
 
 /**
  * Walk up the scope tree until we hit either a Function or reach the
- * very top at hit Program.
+ * very top and hit Program.
  */
 
 Scope.prototype.getFunctionParent = function () {
@@ -491,6 +492,10 @@ each({
   binding: "Binding",
   type: "Type"
 }, function (title, type) {
+  Scope.prototype[type + "Equals"] = function (id, node) {
+    return this["get" + title](id) === node;
+  };
+
   each([
     "get",
     "has",

lib/6to5/traverse/index.js

@@ -1,274 +0,0 @@
-"use strict";
-
-module.exports = traverse;
-
-/* jshint maxparams:7 */
-
-var Scope    = require("./scope");
-var t        = require("../types");
-var contains = require("lodash/collection/contains");
-var flatten  = require("lodash/array/flatten");
-var compact  = require("lodash/array/compact");
-
-function TraversalContext(scope) {
-  this.shouldFlatten = false;
-  this.shouldRemove  = false;
-  this.shouldSkip    = false;
-  this.shouldStop    = false;
-  this.scope         = scope;
-}
-
-TraversalContext.prototype.flatten = function () {
-  this.shouldFlatten = true;
-};
-
-TraversalContext.prototype.remove = function () {
-  this.shouldRemove = true;
-  this.shouldSkip   = true;
-};
-
-TraversalContext.prototype.skip = function () {
-  this.shouldSkip = true;
-};
-
-TraversalContext.prototype.stop = function () {
-  this.shouldStop = true;
-  this.shouldSkip = true;
-};
-
-TraversalContext.prototype.reset = function () {
-  this.shouldRemove = false;
-  this.shouldSkip   = false;
-  this.shouldStop   = false;
-};
-
-TraversalContext.prototype.maybeRemove = function (obj, key) {
-  if (this.shouldRemove) {
-    obj[key] = null;
-    this.flatten();
-  }
-};
-
-TraversalContext.prototype.replaceNode = function (obj, key, node, replacement, scope) {
-  var isArray = Array.isArray(replacement);
-
-  // inherit comments from original node to the first replacement node
-  var inheritTo = replacement;
-  if (isArray) inheritTo = replacement[0];
-  if (inheritTo) t.inheritsComments(inheritTo, node);
-
-  // replace the node
-  obj[key] = replacement;
-
-  var file = this.scope && this.scope.file;
-  if (file) {
-    if (isArray) {
-      for (var i = 0; i < replacement.length; i++) {
-        file.checkNode(replacement[i], scope);
-      }
-    } else {
-      file.checkNode(replacement, scope);
-    }
-  }
-
-  // we're replacing a statement or block node with an array of statements so we better
-  // ensure that it's a block
-  if (isArray && contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
-    t.ensureBlock(obj, key);
-  }
-
-  if (isArray) {
-    this.flatten();
-  }
-};
-
-TraversalContext.prototype.call = function (fn, obj, key, node, parent, scope, state) {
-  var replacement = fn(node, parent, scope, this, state);
-
-  if (replacement) {
-    this.replaceNode(obj, key, node, replacement, scope);
-    node = replacement;
-  }
-
-  this.maybeRemove(obj, key);
-
-  return node;
-};
-
-TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent, state) {
-  this.reset();
-
-  var node = obj[key];
-
-  // type is blacklisted
-  if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) {
-    return;
-  }
-
-  var ourScope = scope;
-  // we're entering a new scope so let's construct it!
-  if (!opts.noScope && t.isScope(node)) {
-    ourScope = new Scope(node, parent, scope);
-  }
-
-  node = this.call(opts.enter, obj, key, node, parent, ourScope, state);
-
-  if (this.shouldSkip) {
-    return this.shouldStop;
-  }
-
-  if (Array.isArray(node)) {
-    // traverse over these replacement nodes we purposely don't call exitNode
-    // as the original node has been destroyed
-    for (var i = 0; i < node.length; i++) {
-      traverseNode(node[i], opts, ourScope, state);
-    }
-  } else {
-    traverseNode(node, opts, ourScope, state);
-    this.call(opts.exit, obj, key, node, parent, ourScope, state);
-  }
-
-  return this.shouldStop;
-};
-
-TraversalContext.prototype.visit = function (node, key, opts, scope, state) {
-  var nodes = node[key];
-  if (!nodes) return;
-
-  if (!Array.isArray(nodes)) {
-    return this.visitNode(node, key, opts, scope, node, state);
-  }
-
-  if (nodes.length === 0) {
-    return;
-  }
-
-  for (var i = 0; i < nodes.length; i++) {
-    if (nodes[i] && this.visitNode(nodes, i, opts, scope, node, state)) {
-      return true;
-    }
-  }
-
-  if (this.shouldFlatten) {
-    node[key] = flatten(node[key]);
-
-    if (key === "body") {
-      // we can safely compact this
-      node[key] = compact(node[key]);
-    }
-  }
-};
-
-function traverseNode(node, opts, scope, state) {
-  var keys = t.VISITOR_KEYS[node.type];
-  if (!keys) return;
-
-  var context = new TraversalContext(scope);
-  for (var i = 0; i < keys.length; i++) {
-    if (context.visit(node, keys[i], opts, scope, state)) {
-      return;
-    }
-  }
-}
-
-function traverse(parent, opts, scope, state) {
-  if (!parent) return;
-
-  if (!opts.noScope && !scope) {
-    if (parent.type !== "Program" && parent.type !== "File") {
-      throw new Error("Must pass a scope unless traversing a Program/File got a " + parent.type + " node");
-    }
-  }
-
-  if (!opts) opts = {};
-  if (!opts.enter) opts.enter = function () { };
-  if (!opts.exit) opts.exit = function () { };
-
-  // array of nodes
-  if (Array.isArray(parent)) {
-    for (var i = 0; i < parent.length; i++) {
-      traverseNode(parent[i], opts, scope, state);
-    }
-  } else {
-    traverseNode(parent, opts, scope, state);
-  }
-}
-
-function clearNode(node) {
-  node._declarations = null;
-  node.extendedRange = null;
-  node._scopeInfo = null;
-  node.tokens = null;
-  node.range = null;
-  node.start = null;
-  node.end = null;
-  node.loc = null;
-  node.raw = null;
-
-  if (Array.isArray(node.trailingComments)) {
-    clearComments(node.trailingComments);
-  }
-
-  if (Array.isArray(node.leadingComments)) {
-    clearComments(node.leadingComments);
-  }
-}
-
-var clearVisitor = {
-  noScope: true,
-  enter: clearNode
-};
-
-function clearComments(comments) {
-  for (var i = 0; i < comments.length; i++) {
-    clearNode(comments[i]);
-  }
-}
-
-traverse.removeProperties = function (tree) {
-  clearNode(tree);
-  traverse(tree, clearVisitor);
-
-  return tree;
-};
-
-traverse.explode = function (obj) {
-  for (var type in obj) {
-    var fns = obj[type];
-
-    var aliases = t.FLIPPED_ALIAS_KEYS[type];
-    if (aliases) {
-      for (var i = 0; i < aliases.length; i++) {
-        obj[aliases[i]] = fns;
-      }
-    }
-  }
-  return obj;
-};
-
-function hasBlacklistedType(node, parent, scope, context, state) {
-  if (node.type === state.type) {
-    state.has = true;
-    context.skip();
-  }
-}
-
-traverse.hasType = function (tree, scope, type, blacklistTypes) {
-  // the node we're searching in is blacklisted
-  if (contains(blacklistTypes, tree.type)) return false;
-
-  // the type we're looking for is the same as the passed node
-  if (tree.type === type) return true;
-
-  var state = {
-    has:  false,
-    type: type
-  };
-
-  traverse(tree, {
-    blacklist: blacklistTypes,
-    enter: hasBlacklistedType
-  }, scope, state);
-
-  return state.has;
-};

lib/6to5/types/index.js

@@ -1,14 +1,14 @@
 "use strict";
 
 var toFastProperties = require("../helpers/to-fast-properties");
+var defaults         = require("lodash/object/defaults");
+var isString         = require("lodash/lang/isString");
+var compact          = require("lodash/array/compact");
 var esutils          = require("esutils");
 var object           = require("../helpers/object");
 var Node             = require("./node");
 var each             = require("lodash/collection/each");
 var uniq             = require("lodash/array/uniq");
-var compact          = require("lodash/array/compact");
-var defaults         = require("lodash/object/defaults");
-var isString         = require("lodash/lang/isString");
 
 var t = exports;
 

lib/6to5/util.js

@@ -2,23 +2,21 @@
 
 require("./patch");
 
-var estraverse = require("estraverse");
-var codeFrame  = require("./helpers/code-frame");
-var traverse   = require("./traverse");
-var debug      = require("debug/node");
-var acorn      = require("acorn-6to5");
-var path       = require("path");
-var util       = require("util");
-var fs         = require("fs");
-var t          = require("./types");
-var each       = require("lodash/collection/each");
+var cloneDeep  = require("lodash/lang/cloneDeep");
+var contains   = require("lodash/collection/contains");
+var traverse   = require("./traversal");
 var isNumber   = require("lodash/lang/isNumber");
 var isString   = require("lodash/lang/isString");
 var isRegExp   = require("lodash/lang/isRegExp");
 var isEmpty    = require("lodash/lang/isEmpty");
-var cloneDeep  = require("lodash/lang/cloneDeep");
+var parse      = require("./helpers/parse");
+var debug      = require("debug/node");
+var path       = require("path");
+var util       = require("util");
+var each       = require("lodash/collection/each");
 var has        = require("lodash/object/has");
-var contains   = require("lodash/collection/contains");
+var fs         = require("fs");
+var t          = require("./types");
 
 exports.inherits = util.inherits;
 
@@ -81,7 +79,7 @@ exports.sourceMapToComment = function (map) {
 };
 
 var templateVisitor = {
-  enter: function (node, parent, scope, context, nodes) {
+  enter: function (node, parent, scope, nodes) {
     if (t.isIdentifier(node) && has(nodes, node.name)) {
       return nodes[node.name];
     }
@@ -123,61 +121,8 @@ exports.repeat = function (width, cha) {
   return result;
 };
 
-exports.normalizeAst = function (ast, comments, tokens) {
-  if (ast && ast.type === "Program") {
-    return t.file(ast, comments || [], tokens || []);
-  } else {
-    throw new Error("Not a valid ast?");
-  }
-};
-
-exports.parse = function (opts, code, callback) {
-  try {
-    var comments = [];
-    var tokens   = [];
-
-    var ast = acorn.parse(code, {
-      allowImportExportEverywhere: opts.allowImportExportEverywhere,
-      allowReturnOutsideFunction:  !opts._anal,
-      ecmaVersion:                 opts.experimental ? 7 : 6,
-      playground:                  opts.playground,
-      strictMode:                  opts.strictMode,
-      onComment:                   comments,
-      locations:                   true,
-      onToken:                     tokens,
-      ranges:                      true
-    });
-
-    estraverse.attachComments(ast, comments, tokens);
-
-    ast = exports.normalizeAst(ast, comments, tokens);
-
-    if (callback) {
-      return callback(ast);
-    } else {
-      return ast;
-    }
-  } catch (err) {
-    if (!err._6to5) {
-      err._6to5 = true;
-      var message = opts.filename + ": " + err.message;
-
-      var loc = err.loc;
-      if (loc) {
-        var frame = codeFrame(code, loc.line, loc.column + 1);
-        message += frame;
-      }
-
-      if (err.stack) err.stack = err.stack.replace(err.message, message);
-      err.message = message;
-    }
-
-    throw err;
-  }
-};
-
 exports.parseTemplate = function (loc, code) {
-  var ast = exports.parse({ filename: loc }, code).program;
+  var ast = parse({ filename: loc }, code).program;
   return traverse.removeProperties(ast);
 };
 

package.json

@@ -1,22 +1,21 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "3.3.10",
+  "version": "3.4.0",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://6to5.org/",
   "repository": "6to5/6to5",
   "preferGlobal": true,
-  "main": "lib/6to5/index.js",
+  "main": "lib/6to5/api/node.js",
+  "browser": {
+    "./lib/6to5/api/register/node.js": "./lib/6to5/api/register/browser.js"
+  },
   "bin": {
     "6to5": "./bin/6to5/index.js",
     "6to5-minify": "./bin/6to5-minify",
     "6to5-node": "./bin/6to5-node",
     "6to5-runtime": "./bin/6to5-runtime"
   },
-  "browser": {
-    "./lib/6to5/index.js": "./lib/6to5/browser.js",
-    "./lib/6to5/register.js": "./lib/6to5/register-browser.js"
-  },
   "keywords": [
     "harmony",
     "classes",

packages/6to5-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5-runtime",
   "description": "6to5 selfContained runtime",
-  "version": "3.3.9",
+  "version": "3.3.12",
   "repository": "6to5/6to5",
   "author": "Sebastian McKenzie <sebmck@gmail.com>"
 }

register.js

@@ -1 +1 @@
-module.exports = require("./lib/6to5/register");
+module.exports = require("./lib/6to5/api/register/node");

test/api.js

@@ -1,6 +1,6 @@
 var transform = require("../lib/6to5/transformation");
 var assert    = require("assert");
-var File      = require("../lib/6to5/file");
+var File      = require("../lib/6to5/transformation/file");
 
 suite("api", function () {
   test("{ code: false }", function () {

test/detection.js

@@ -1,10 +1,10 @@
 var detect = require("../lib/6to5/detection");
 var assert = require("assert");
-var util   = require("../lib/6to5/util");
+var parse  = require("../lib/6to5/helpers/parse");
 
 suite("detection", function () {
   var checkSyntax = function (code, name) {
-    var ast = util.parse({
+    var ast = parse({
       experimental: true
     }, code);
 

test/fixtures/esnext/es6-classes/super-change-proto.js

@@ -0,0 +1,21 @@
+var log = '';
+
+class Base {
+  p() { log += '[Base]'; }
+}
+
+class OtherBase {
+  p() { log += '[OtherBase]'; }
+}
+
+class Derived extends Base {
+  p() {
+    log += '[Derived]';
+    super.p();
+    Derived.prototype.__proto__ = OtherBase.prototype;
+    super.p();
+  }
+}
+
+new Derived().p();
+assert.equal(log, '[Derived][Base][OtherBase]');

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

@@ -15,14 +15,14 @@ var Test = (function (Foo) {
     _classCallCheck(this, Test);
 
     woops["super"].test();
-    _get(Foo.prototype, "constructor", this).call(this);
-    _get(Foo.prototype, "test", this).call(this);
+    _get(Object.getPrototypeOf(Test.prototype), "constructor", this).call(this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
 
-    _get(Foo.prototype, "constructor", this).apply(this, arguments);
-    (_get2 = _get(Foo.prototype, "constructor", this)).call.apply(_get2, [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)));
 
-    _get(Foo.prototype, "test", this).apply(this, arguments);
-    (_get3 = _get(Foo.prototype, "test", this)).call.apply(_get3, [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);
@@ -31,9 +31,9 @@ var Test = (function (Foo) {
     foo: {
       value: function foo() {
         var _get2;
-        _get(Foo, "foo", this).call(this);
-        _get(Foo, "foo", this).apply(this, arguments);
-        (_get2 = _get(Foo, "foo", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
+        _get(Object.getPrototypeOf(Test), "foo", this).call(this);
+        _get(Object.getPrototypeOf(Test), "foo", this).apply(this, arguments);
+        (_get2 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       configurable: true
@@ -42,9 +42,9 @@ var Test = (function (Foo) {
     test: {
       value: function test() {
         var _get2;
-        _get(Foo.prototype, "test", this).call(this);
-        _get(Foo.prototype, "test", this).apply(this, arguments);
-        (_get2 = _get(Foo.prototype, "test", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
+        _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
+        _get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
+        (_get2 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get2, [this, "test"].concat(_slice.call(arguments)));
       },
       writable: true,
       configurable: true

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

@@ -10,8 +10,8 @@ var Test = (function (Foo) {
   function Test() {
     _classCallCheck(this, Test);
 
-    _get(Foo.prototype, "test", this);
-    _get(Foo.prototype, "test", this).whatever;
+    _get(Object.getPrototypeOf(Test.prototype), "test", this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever;
   }
 
   _inherits(Test, Foo);

test/fixtures/transformation/es6-classes/bare-super/options.json

@@ -1,3 +1,3 @@
 {
-  "throws": "illegal use of bare super"
+  "throws": "Illegal use of bare super"
 }

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

@@ -12,8 +12,8 @@ var Test = (function (Foo) {
   function Test() {
     _classCallCheck(this, Test);
 
-    _get(Foo.prototype, "test", this).whatever();
-    _get(Foo.prototype, "test", this).call(this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever();
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
   }
 
   _inherits(Test, Foo);
@@ -21,7 +21,7 @@ var Test = (function (Foo) {
   _prototypeProperties(Test, {
     test: {
       value: function test() {
-        return _get(Foo, "wow", this).call(this);
+        return _get(Object.getPrototypeOf(Test), "wow", this).call(this);
       },
       writable: true,
       configurable: true

test/fixtures/transformation/es6-classes/super-change-proto/exec.js

@@ -0,0 +1,21 @@
+var log = '';
+
+class Base {
+  p() { log += '[Base]'; }
+}
+
+class OtherBase {
+  p() { log += '[OtherBase]'; }
+}
+
+class Derived extends Base {
+  p() {
+    log += '[Derived]';
+    super.p();
+    Derived.prototype.__proto__ = OtherBase.prototype;
+    super.p();
+  }
+}
+
+new Derived().p();
+assert.equal(log, '[Derived][Base][OtherBase]');

test/fixtures/transformation/es6-classes/super-function-fallback/expected.js

@@ -7,5 +7,5 @@ var _classCallCheck = function (instance, Constructor) { if (!(instance instance
 var Test = function Test() {
   _classCallCheck(this, Test);
 
-  _get(Function.prototype, "hasOwnProperty", this).call(this, "test");
-};
+  _get(Object.getPrototypeOf(Test.prototype), "hasOwnProperty", this).call(this, "test");
+};

test/fixtures/transformation/es6-destructuring/member-expression/expected.js

@@ -8,4 +8,4 @@ var _ref2 = _slicedToArray(_ref, 2);
 
 foo.foo = _ref2[0];
 foo.bar = _ref2[1];
-;
+;

test/fixtures/transformation/es6-modules-common-standard/export/actual.js

@@ -0,0 +1,3 @@
+export function foo() {}
+export default foo;
+export { foo as default, foo };