v3.3.10

Concatenate adjacent string literals in JSX

CHANGELOG.md

@@ -11,7 +11,19 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
-## 3.3.8
+## 3.3.10
+
+ * **Internal**
+  * Restructure transformers so they're only ran if the AST contains nodes that they need to worry about. Improves transpilation speed significantly.
+ * **Bug Fix**
+  * Fix source maps not tracking end of node locations.
+ * **Spec Compliancy**
+  * Use static super references as the home object is actually done at definition time.
+ * **Polish**
+  * Force the `es6.destructuring` transformer to be whitelisted when the `es7.objectSpread` transformer is.
+  * Join sibling string literals when creating JSX.
+
+## 3.3.9
 
  * **Bug Fix**
   * Fix super inside of functions.

lib/6to5/file.js

@@ -53,7 +53,7 @@ File.helpers = [
   "get",
   "set",
   "class-call-check",
-  "class-super-constructor-call"
+  "object-destructuring-empty"
 ];
 
 File.validOptions = [
@@ -182,6 +182,7 @@ File.prototype.buildTransformers = function () {
 
     if (pass.canRun(file)) {
       stack.push(pass);
+
       if (transformer.secondPass) {
         secondaryStack.push(pass);
       }
@@ -353,6 +354,8 @@ File.prototype.transform = function (ast) {
     modFormatter.init();
   }
 
+  this.checkNode(ast);
+
   var astRun = function (key) {
     each(self.transformerStack, function (pass) {
       pass.astRun(key);
@@ -368,6 +371,30 @@ File.prototype.transform = function (ast) {
   astRun("exit");
 };
 
+var checkTransformerVisitor = {
+  enter: function (node, parent, scope, context, state) {
+    state.check(node, scope);
+  }
+};
+
+File.prototype.checkNode = function (node, scope) {
+  var self = this;
+  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);
+
+  scope.traverse(node, checkTransformerVisitor, {
+    check: check
+  });
+};
+
 File.prototype.generate = function () {
   var opts = this.opts;
   var ast  = this.ast;

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

@@ -94,8 +94,10 @@ exports.Literal = function (node) {
     });
 
     this.push(val);
-  } else if (type === "boolean" || type === "number") {
-    this.push(JSON.stringify(val));
+  } else if (type === "number") {
+    this.push(val + "");
+  } else if (type === "boolean") {
+    this.push(val ? "true" : "false");
   } else if (node.regex) {
     this.push("/" + node.regex.pattern + "/" + node.regex.flags);
   } else if (val === null) {

lib/6to5/generation/index.js

@@ -190,7 +190,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     newline(true);
 
     if (opts.before) opts.before();
-    this.map.mark(node);
+    this.map.mark(node, "start");
 
     this[node.type](node, this.buildPrint(node), parent);
 
@@ -200,6 +200,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
     }
     if (needsParens) this.push(")");
 
+    this.map.mark(node, "end");
     if (opts.after) opts.after();
 
     newline(false);

lib/6to5/generation/source-map.js

@@ -30,7 +30,7 @@ SourceMap.prototype.get = function () {
   }
 };
 
-SourceMap.prototype.mark = function (node) {
+SourceMap.prototype.mark = function (node, type) {
   var loc = node.loc;
   if (!loc) return; // no location info
 
@@ -46,7 +46,7 @@ SourceMap.prototype.mark = function (node) {
     column: position.column
   };
 
-  var original = loc.start;
+  var original = loc[type];
 
   map.addMapping({
     source: this.opts.sourceFileName,

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

@@ -1,8 +1,7 @@
 "use strict";
 
-var traverse = require("../../traverse");
-var util     = require("../../util");
-var t        = require("../../types");
+var util = require("../../util");
+var t    = require("../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
@@ -35,7 +34,7 @@ exports.property = function (node, file, scope) {
     outerDeclar: scope.getBinding(id),
   };
 
-  traverse(node, visitor, scope, state);
+  scope.traverse(node, visitor, state);
 
   if (state.selfReference) {
     // todo: support generators

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

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../traverse");
-var t        = require("../../types");
+var t = require("../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context) {
@@ -23,7 +22,7 @@ module.exports = function (node, callId, scope) {
   node.async = false;
   node.generator = true;
 
-  traverse(node, visitor, scope);
+  scope.traverse(node, visitor);
 
   var call = t.callExpression(callId, [node]);
   var id = node.id;

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

@@ -2,8 +2,7 @@
 
 module.exports = ReplaceSupers;
 
-var traverse = require("../../traverse");
-var t        = require("../../types");
+var t = require("../../types");
 
 /**
  * Description
@@ -38,12 +37,7 @@ ReplaceSupers.prototype.setSuperProperty = function (property, value, isStatic,
   return t.callExpression(
     this.file.addHelper("set"),
     [
-      t.callExpression(
-        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
-        [
-          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
-        ]
-      ),
+      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
       isComputed ? property : t.literal(property.name),
       value,
       thisExpression
@@ -65,63 +59,17 @@ ReplaceSupers.prototype.setSuperProperty = function (property, value, isStatic,
  * @returns {Node}
  */
 
-ReplaceSupers.prototype.superProperty = function (property, isStatic, isComputed, thisExpression) {
+ReplaceSupers.prototype.getSuperProperty = function (property, isStatic, isComputed, thisExpression) {
   return t.callExpression(
     this.file.addHelper("get"),
     [
-      t.callExpression(
-        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
-        [
-          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
-        ]
-      ),
+      isStatic ? this.superName : t.memberExpression(this.superName, t.identifier("prototype")),
       isComputed ? property : t.literal(property.name),
       thisExpression
     ]
   );
 };
 
-/**
- * Description
- *
- * @param {Object} node
- * @param {Object} id
- * @param {Object} parent
- * @returns {Object}
- */
-
-ReplaceSupers.prototype.looseSuperProperty = function (methodNode, id, parent) {
-  var methodName = methodNode.key;
-  var superName  = this.superName || t.identifier("Function");
-
-  if (parent.property === id) {
-    return;
-  } else if (t.isCallExpression(parent, { callee: id })) {
-    // super(); -> ClassName.prototype.MethodName.call(this);
-    parent.arguments.unshift(t.thisExpression());
-
-    if (methodName.name === "constructor") {
-      // constructor() { super(); }
-      return t.memberExpression(superName, t.identifier("call"));
-    } else {
-      id = superName;
-
-      // foo() { super(); }
-      if (!methodNode.static) {
-        id = t.memberExpression(id, t.identifier("prototype"));
-      }
-
-      id = t.memberExpression(id, methodName, methodNode.computed);
-      return t.memberExpression(id, t.identifier("call"));
-    }
-  } else if (t.isMemberExpression(parent) && !methodNode.static) {
-    // super.test -> ClassName.prototype.test
-    return t.memberExpression(superName, t.identifier("prototype"));
-  } else {
-    return superName;
-  }
-};
-
 /**
  * Description
  */
@@ -167,7 +115,7 @@ var visitor = {
 
 ReplaceSupers.prototype.traverseLevel = function (node, topLevel) {
   var state = { self: this, topLevel: topLevel };
-  traverse(node, visitor, this.scope, state);
+  this.scope.traverse(node, visitor, state);
 };
 
 /**
@@ -186,6 +134,47 @@ ReplaceSupers.prototype.getThisReference = function () {
   }
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} id
+ * @param {Object} parent
+ * @returns {Object}
+ */
+
+ReplaceSupers.prototype.getLooseSuperProperty = function (methodNode, id, parent) {
+  var methodName = methodNode.key;
+  var superName  = this.superName || t.identifier("Function");
+
+  if (parent.property === id) {
+    return;
+  } else if (t.isCallExpression(parent, { callee: id })) {
+    // super(); -> ClassName.prototype.MethodName.call(this);
+    parent.arguments.unshift(t.thisExpression());
+
+    if (methodName.name === "constructor") {
+      // constructor() { super(); }
+      return t.memberExpression(superName, t.identifier("call"));
+    } else {
+      id = superName;
+
+      // foo() { super(); }
+      if (!methodNode.static) {
+        id = t.memberExpression(id, t.identifier("prototype"));
+      }
+
+      id = t.memberExpression(id, methodName, methodNode.computed);
+      return t.memberExpression(id, t.identifier("call"));
+    }
+  } else if (t.isMemberExpression(parent) && !methodNode.static) {
+    // super.test -> ClassName.prototype.test
+    return t.memberExpression(superName, t.identifier("prototype"));
+  } else {
+    return superName;
+  }
+};
+
 /**
  * Description
  *
@@ -196,7 +185,7 @@ ReplaceSupers.prototype.getThisReference = function () {
 
 ReplaceSupers.prototype.looseHandle = function (getThisReference, node, parent) {
   if (t.isIdentifier(node, { name: "super" })) {
-    return this.looseSuperProperty(this.methodNode, node, parent);
+    return this.getLooseSuperProperty(this.methodNode, node, parent);
   } else if (t.isCallExpression(node)) {
     var callee = node.callee;
     if (!t.isMemberExpression(callee)) return;
@@ -269,7 +258,7 @@ ReplaceSupers.prototype.specHandle = function (getThisReference, node, parent) {
   if (!property) return;
 
   thisReference = getThisReference();
-  var superProperty = this.superProperty(property, methodNode.static, computed, thisReference);
+  var superProperty = this.getSuperProperty(property, methodNode.static, computed, thisReference);
   if (args) {
     if (args.length === 1 && t.isSpreadElement(args[0])) {
       // super(...arguments);

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

@@ -2,7 +2,6 @@
 
 module.exports = DefaultFormatter;
 
-var traverse = require("../../traverse");
 var object   = require("../../helpers/object");
 var util     = require("../../util");
 var t        = require("../../types");
@@ -60,7 +59,7 @@ var exportsVisitor = {
 };
 
 DefaultFormatter.prototype.getLocalExports = function () {
-  traverse(this.file.ast, exportsVisitor, this.file.scope, this);
+  this.file.scope.traverse(this.file.ast, exportsVisitor, this);
 };
 
 var importsVisitor = {
@@ -74,7 +73,7 @@ var importsVisitor = {
 };
 
 DefaultFormatter.prototype.getLocalImports = function () {
-  traverse(this.file.ast, importsVisitor, this.file.scope, this);
+  this.file.scope.traverse(this.file.ast, importsVisitor, this);
 };
 
 var remapVisitor = {
@@ -116,7 +115,7 @@ var remapVisitor = {
 
 DefaultFormatter.prototype.remapAssignments = function () {
   if (this.hasLocalImports) {
-    traverse(this.file.ast, remapVisitor, this.file.scope, this);
+    this.file.scope.traverse(this.file.ast, remapVisitor, this);
   }
 };
 

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

@@ -5,7 +5,6 @@ module.exports = SystemFormatter;
 var DefaultFormatter = require("./_default");
 var AMDFormatter     = require("./amd");
 var useStrict        = require("../helpers/use-strict");
-var traverse         = require("../../traverse");
 var util             = require("../../util");
 var t                = require("../../types");
 var last             = require("lodash/array/last");
@@ -97,7 +96,7 @@ SystemFormatter.prototype.buildRunnerSetters = function (block, hoistDeclarators
       hoistDeclarators: hoistDeclarators
     };
 
-    traverse(block, runnerSettersVisitor, scope, state);
+    scope.traverse(block, runnerSettersVisitor, state);
 
     return t.functionExpression(null, [uid], t.blockStatement(state.nodes));
   }));
@@ -182,7 +181,7 @@ SystemFormatter.prototype.transform = function (ast) {
   var returnStatement = handlerBody.pop();
 
   // hoist up all variable declarations
-  traverse(block, hoistVariablesVisitor, this.file.scope, hoistDeclarators);
+  this.file.scope.traverse(block, hoistVariablesVisitor, hoistDeclarators);
 
   if (hoistDeclarators.length) {
     var hoistDeclar = t.variableDeclaration("var", hoistDeclarators);
@@ -191,7 +190,7 @@ SystemFormatter.prototype.transform = function (ast) {
   }
 
   // hoist up function declarations for circular references
-  traverse(block, hoistFunctionsVisitor, this.file.scope, handlerBody);
+  this.file.scope.traverse(block, hoistFunctionsVisitor, handlerBody);
 
   handlerBody.push(returnStatement);
 

lib/6to5/transformation/templates/class-super-constructor-call.js

@@ -1,3 +1,3 @@
-if (Object.getPrototypeOf(CLASS_NAME) !== null) {
-  Object.getPrototypeOf(CLASS_NAME).apply(this, arguments);
+if (SUPER_NAME != null) {
+  SUPER_NAME.apply(this, arguments);
 }

lib/6to5/transformation/templates/object-destructuring-empty.js

@@ -0,0 +1,3 @@
+(function (obj) {
+  if (obj == null) throw new TypeError("Cannot destructure undefined");
+});

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

@@ -1,6 +1,5 @@
 module.exports = TransformerPass;
 
-var traverse = require("../traverse");
 var util     = require("../util");
 var contains = require("lodash/collection/contains");
 
@@ -11,11 +10,14 @@ var contains = require("lodash/collection/contains");
 
 function TransformerPass(file, transformer) {
   this.transformer = transformer;
+  this.shouldRun   = !transformer.check;
   this.handlers    = transformer.handlers;
   this.file        = file;
 }
 
 TransformerPass.prototype.astRun = function (key) {
+  if (!this.shouldRun) return;
+
   var handlers = this.handlers;
   var file = this.file;
 
@@ -29,23 +31,39 @@ TransformerPass.prototype.canRun = function () {
 
   var opts = this.file.opts;
   var key  = transformer.key;
+
+  // internal
   if (key[0] === "_") return true;
 
+  // blacklist
   var blacklist = opts.blacklist;
   if (blacklist.length && contains(blacklist, key)) return false;
 
+  // whitelist
   var whitelist = opts.whitelist;
   if (whitelist.length && !contains(whitelist, key)) return false;
 
+  // optional
   if (transformer.optional && !contains(opts.optional, key)) return false;
 
+  // experimental
   if (transformer.experimental && !opts.experimental) return false;
 
+  // playground
   if (transformer.playground && !opts.playground) return false;
 
   return true;
 };
 
+TransformerPass.prototype.checkNode = function (node) {
+  var check = this.transformer.check;
+  if (check) {
+    return this.shouldRun = check(node);
+  } else {
+    return true;
+  }
+};
+
 var transformVisitor = {
   enter: function (node, parent, scope, context, state) {
     var fns = state.handlers[node.type];
@@ -61,6 +79,8 @@ var transformVisitor = {
 };
 
 TransformerPass.prototype.transform = function () {
+  if (!this.shouldRun) return;
+
   var file = this.file;
 
   util.debug(file.opts.filename + ": Running transformer " + this.transformer.key);
@@ -68,7 +88,7 @@ TransformerPass.prototype.transform = function () {
   this.astRun("before");
 
   var state = { file: file, handlers: this.handlers, pass: this };
-  traverse(file.ast, transformVisitor, file.scope, state);
+  file.scope.traverse(file.ast, transformVisitor, state);
 
   this.astRun("after");
 };

lib/6to5/transformation/transformer.js

@@ -16,13 +16,16 @@ var each            = require("lodash/collection/each");
 
 function Transformer(key, transformer, opts) {
   this.manipulateOptions = transformer.manipulateOptions;
-  this.experimental      = !!transformer.experimental;
-  this.playground        = !!transformer.playground;
-  this.secondPass        = !!transformer.secondPass;
-  this.optional          = !!transformer.optional;
-  this.handlers          = this.normalize(transformer);
-  this.opts              = opts || {};
-  this.key               = key;
+  this.check             = transformer.check;
+
+  this.experimental = !!transformer.experimental;
+  this.playground   = !!transformer.playground;
+  this.secondPass   = !!transformer.secondPass;
+  this.optional     = !!transformer.optional;
+
+  this.handlers = this.normalize(transformer);
+  this.opts     = opts || {};
+  this.key      = key;
 }
 
 Transformer.prototype.normalize = function (transformer) {

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

@@ -12,7 +12,8 @@
   "generatorComprehension": "es7.comprehensions",
   "arrowFunctions": "es6.arrowFunctions",
   "classes": "es6.classes",
-  "objectSpread": "es7.objectSpread",
+  "objectSpread": "es7.objectRestSpread",
+  "es7.objectSpread": "es7.objectRestSpread",
   "exponentiationOperator": "es7.exponentiationOperator",
   "spread": "es6.spread",
   "templateLiterals": "es6.templateLiterals",

lib/6to5/transformation/transformers/es5/properties.mutators.js

@@ -3,6 +3,10 @@
 var defineMap = require("../../helpers/define-map");
 var t         = require("../../../types");
 
+exports.check = function (node) {
+  return t.isProperty(node) && (node.kind === "get" || node.kind === "set");
+};
+
 exports.ObjectExpression = function (node) {
   var mutatorMap = {};
   var hasAny = false;

lib/6to5/transformation/transformers/es6/arrow-functions.js

@@ -2,6 +2,8 @@
 
 var t = require("../../../types");
 
+exports.check = t.isArrowFunctionExpression;
+
 exports.ArrowFunctionExpression = function (node) {
   t.ensureBlock(node);
 

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

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
@@ -46,5 +45,5 @@ exports.BlockStatement = function (node, parent, scope, context, file) {
     file:    file
   };
 
-  traverse(node, visitor, scope, state);
+  scope.traverse(node, visitor, state);
 };

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

@@ -7,6 +7,10 @@ var t        = require("../../../types");
 var values   = require("lodash/object/values");
 var extend   = require("lodash/object/extend");
 
+exports.check = function (node) {
+  return t.isVariableDeclaration(node) && (node.kind === "let" || node.kind === "const");
+};
+
 var isLet = function (node, parent) {
   if (!t.isVariableDeclaration(node)) return false;
   if (node._let) return true;
@@ -126,7 +130,7 @@ var replaceVisitor = {
 
 function traverseReplace(node, parent, scope, remaps) {
   replace(node, parent, scope, null, remaps);
-  traverse(node, replaceVisitor, scope, remaps);
+  scope.traverse(node, replaceVisitor, remaps);
 }
 
 /**
@@ -172,7 +176,7 @@ BlockScoping.prototype.remap = function () {
     traverseReplace(loopParent.update, loopParent, scope, remaps);
   }
 
-  traverse(this.block, replaceVisitor, scope, remaps);
+  scope.traverse(this.block, replaceVisitor, remaps);
 };
 
 /**
@@ -239,7 +243,7 @@ var letReferenceFunctionVisitor = {
 var letReferenceBlockVisitor = {
   enter: function (node, parent, scope, context, state) {
     if (t.isFunction(node)) {
-      traverse(node, letReferenceFunctionVisitor, scope, state);
+      scope.traverse(node, letReferenceFunctionVisitor, state);
       return context.skip();
     }
   }
@@ -292,7 +296,7 @@ BlockScoping.prototype.getLetReferences = function () {
 
   // traverse through this block, stopping on functions and checking if they
   // contain any local let references
-  traverse(this.block, letReferenceBlockVisitor, this.scope, state);
+  this.scope.traverse(this.block, letReferenceBlockVisitor, state);
 
   return state.closurify;
 };
@@ -311,7 +315,7 @@ var loopVisitor = {
 
     if (t.isLoop(node)) {
       state.ignoreLabeless = true;
-      traverse(node, loopVisitor, scope, state);
+      scope.traverse(node, loopVisitor, state);
       state.ignoreLabeless = false;
     }
 
@@ -384,8 +388,8 @@ BlockScoping.prototype.checkLoop = function () {
     map:              {}
   };
 
-  traverse(this.block, loopLabelVisitor, this.scope, state);
-  traverse(this.block, loopVisitor, this.scope, state);
+  this.scope.traverse(this.block, loopLabelVisitor, state);
+  this.scope.traverse(this.block, loopVisitor, state);
 
   return state;
 };

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

@@ -6,6 +6,8 @@ var defineMap     = require("../../helpers/define-map");
 var util          = require("../../../util");
 var t             = require("../../../types");
 
+exports.check = t.isClass;
+
 exports.ClassDeclaration = function (node, parent, scope, context, file) {
   return new Class(node, file, scope, true).run();
 };
@@ -48,7 +50,8 @@ function Class(node, file, scope, isStatement) {
   this.staticMutatorMap   = {};
   this.hasConstructor     = false;
   this.className          = node.id || scope.generateUidIdentifier("class");
-  this.superName          = node.superClass;
+  this.superName          = node.superClass || t.identifier("Function");
+  this.hasSuper           = !!node.superClass;
   this.isLoose            = file.isLoose("es6.classes");
 }
 
@@ -91,7 +94,7 @@ Class.prototype.run = function () {
 
   //
 
-  if (superName) {
+  if (this.hasSuper) {
     closureArgs.push(superName);
 
     if (!t.isIdentifier(superName)) {
@@ -167,7 +170,7 @@ Class.prototype.buildBody = function () {
   }
 
   // we have no constructor, we have a super, and the super doesn't appear to be falsy
-  if (!this.hasConstructor && superName && !t.isFalsyExpression(superName)) {
+  if (!this.hasConstructor && this.hasSuper && !t.isFalsyExpression(superName)) {
     var helperName = "class-super-constructor-call";
     if (this.isLoose) helperName += "-loose";
     constructor.body.body.push(util.template(helperName, {

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

@@ -1,7 +1,10 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
+
+exports.check = function (node) {
+  return t.isVariableDeclaration(node, { kind: "const" });
+};
 
 var visitor = {
   enter: function (node, parent, scope, context, state) {
@@ -33,7 +36,7 @@ var visitor = {
 };
 
 exports.Scope = function (node, parent, scope, context, file) {
-  traverse(node, visitor, scope, {
+  scope.traverse(node, visitor, {
     constants: scope.getAllDeclarationsOfKind("const"),
     file:      file
   });

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

@@ -1,11 +1,20 @@
 "use strict";
 
-// TODO: Clean up
-
 var t = require("../../../types");
 
-var buildVariableAssign = function (opts, id, init) {
-  var op = opts.operator;
+exports.check = t.isPattern;
+
+function Destructuring(opts) {
+  this.blockHoist = opts.blockHoist;
+  this.operator   = opts.operator;
+  this.nodes      = opts.nodes;
+  this.scope      = opts.scope;
+  this.file       = opts.file;
+  this.kind       = opts.kind;
+}
+
+Destructuring.prototype.buildVariableAssignment = function (id, init) {
+  var op = this.operator;
   if (t.isMemberExpression(id)) op = "=";
 
   var node;
@@ -13,47 +22,46 @@ var buildVariableAssign = function (opts, id, init) {
   if (op) {
     node = t.expressionStatement(t.assignmentExpression(op, id, init));
   } else {
-    node = t.variableDeclaration(opts.kind, [
+    node = t.variableDeclaration(this.kind, [
       t.variableDeclarator(id, init)
     ]);
   }
 
-  node._blockHoist = opts.blockHoist;
+  node._blockHoist = this.blockHoist;
 
   return node;
 };
 
-var buildVariableDeclar = function (opts, id, init) {
+Destructuring.prototype.buildVariableDeclaration = function (id, init) {
   var declar = t.variableDeclaration("var", [
     t.variableDeclarator(id, init)
   ]);
-  declar._blockHoist = opts.blockHoist;
+  declar._blockHoist = this.blockHoist;
   return declar;
 };
 
-var push = function (opts, nodes, elem, parentId) {
+Destructuring.prototype.push = function (elem, parentId) {
   if (t.isObjectPattern(elem)) {
-    pushObjectPattern(opts, nodes, elem, parentId);
+    this.pushObjectPattern(elem, parentId);
   } else if (t.isArrayPattern(elem)) {
-    pushArrayPattern(opts, nodes, elem, parentId);
+    this.pushArrayPattern(elem, parentId);
   } else if (t.isAssignmentPattern(elem)) {
-    pushAssignmentPattern(opts, nodes, elem, parentId);
+    this.pushAssignmentPattern(elem, parentId);
   } else {
-    nodes.push(buildVariableAssign(opts, elem, parentId));
+    this.nodes.push(this.buildVariableAssignment(elem, parentId));
   }
 };
 
-var pushAssignmentPattern = function (opts, nodes, pattern, parentId) {
-  var tempParentId = opts.scope.generateUidBasedOnNode(parentId, opts.file);
+Destructuring.prototype.pushAssignmentPattern = function (pattern, parentId) {
+  var tempParentId = this.scope.generateUidBasedOnNode(parentId);
 
   var declar = t.variableDeclaration("var", [
     t.variableDeclarator(tempParentId, parentId)
   ]);
-  declar._blockHoist = opts.blockHoist;
-  nodes.push(declar);
+  declar._blockHoist = this.blockHoist;
+  this.nodes.push(declar);
 
-  nodes.push(buildVariableAssign(
-    opts,
+  this.nodes.push(this.buildVariableAssignment(
     pattern.left,
     t.conditionalExpression(
       t.binaryExpression("===", tempParentId, t.identifier("undefined")),
@@ -63,72 +71,88 @@ var pushAssignmentPattern = function (opts, nodes, pattern, parentId) {
   ));
 };
 
-var pushObjectPattern = function (opts, nodes, pattern, parentId) {
+Destructuring.prototype.pushObjectSpread = function (pattern, parentId, prop, i) {
+  // get all the keys that appear in this object before the current spread
+  var keys = [];
+  for (var i2 = 0; i2 < pattern.properties.length; i2++) {
+    var prop2 = pattern.properties[i2];
+
+    if (i2 >= i) break;
+    if (t.isSpreadProperty(prop2)) continue;
+
+    var key = prop2.key;
+    if (t.isIdentifier(key)) {
+      key = t.literal(prop2.key.name);
+    }
+    keys.push(key);
+  }
+  keys = t.arrayExpression(keys);
+
+  var value = t.callExpression(this.file.addHelper("object-without-properties"), [parentId, keys]);
+  this.nodes.push(this.buildVariableAssignment(prop.argument, value));
+};
+
+Destructuring.prototype.pushObjectProperty = function (prop, parentId) {
+  if (t.isLiteral(prop.key)) prop.computed = true;
+
+  var pattern2   = prop.value;
+  var patternId2 = t.memberExpression(parentId, prop.key, prop.computed);
+
+  if (t.isPattern(pattern2)) {
+    this.push(pattern2, patternId2);
+  } else {
+    this.nodes.push(this.buildVariableAssignment(pattern2, patternId2));
+  }
+};
+
+Destructuring.prototype.pushObjectPattern = function (pattern, parentId) {
+  if (!pattern.properties.length) {
+    this.nodes.push(t.expressionStatement(
+      t.callExpression(this.file.addHelper("object-destructuring-empty"), [parentId])
+    ));
+  }
+
   for (var i = 0; i < pattern.properties.length; i++) {
     var prop = pattern.properties[i];
     if (t.isSpreadProperty(prop)) {
-      // get all the keys that appear in this object before the current spread
-      var keys = [];
-      for (var i2 = 0; i2 < pattern.properties.length; i2++) {
-        var prop2 = pattern.properties[i2];
-
-        if (i2 >= i) break;
-        if (t.isSpreadProperty(prop2)) continue;
-
-        var key = prop2.key;
-        if (t.isIdentifier(key)) {
-          key = t.literal(prop2.key.name);
-        }
-        keys.push(key);
-      }
-      keys = t.arrayExpression(keys);
-
-      var value = t.callExpression(opts.file.addHelper("object-without-properties"), [parentId, keys]);
-      nodes.push(buildVariableAssign(opts, prop.argument, value));
+      this.pushObjectSpread(pattern, parentId, prop, i);
     } else {
-      if (t.isLiteral(prop.key)) prop.computed = true;
-
-      var pattern2   = prop.value;
-      var patternId2 = t.memberExpression(parentId, prop.key, prop.computed);
-
-      if (t.isPattern(pattern2)) {
-        push(opts, nodes, pattern2, patternId2);
-      } else {
-        nodes.push(buildVariableAssign(opts, pattern2, patternId2));
-      }
+      this.pushObjectProperty(prop, parentId);
     }
   }
 };
 
-var pushArrayPattern = function (opts, nodes, pattern, parentId) {
-  if (!pattern.elements) return;
-
-  var i;
-
-  var hasRest = false;
-  for (i = 0; i < pattern.elements.length; i++) {
+var hasRest = function (pattern) {
+  for (var i = 0; i < pattern.elements.length; i++) {
     if (t.isRestElement(pattern.elements[i])) {
-      hasRest = true;
-      break;
+      return true;
     }
   }
+  return false;
+};
 
-  var toArray = opts.file.toArray(parentId, !hasRest && pattern.elements.length);
+Destructuring.prototype.pushArrayPattern = function (pattern, parentId) {
+  if (!pattern.elements) return;
 
-  var _parentId = opts.scope.generateUidBasedOnNode(parentId, opts.file);
-  nodes.push(buildVariableDeclar(opts, _parentId, toArray));
+  // if we have a rest then we need all the elements
+  var count = !hasRest(pattern) && pattern.elements.length;
+
+  var toArray = this.file.toArray(parentId, count);
+
+  var _parentId = this.scope.generateUidBasedOnNode(parentId, this.file);
+  this.nodes.push(this.buildVariableDeclaration(_parentId, toArray));
   parentId = _parentId;
 
-  for (i = 0; i < pattern.elements.length; i++) {
+  for (var i = 0; i < pattern.elements.length; i++) {
     var elem = pattern.elements[i];
-    if (!elem) continue;
 
-    i = +i;
+    // hole
+    if (!elem) continue;
 
     var newPatternId;
 
     if (t.isRestElement(elem)) {
-      newPatternId = opts.file.toArray(parentId);
+      newPatternId = this.file.toArray(parentId);
 
       if (i > 0) {
         newPatternId = t.callExpression(t.memberExpression(newPatternId, t.identifier("slice")), [t.literal(i)]);
@@ -139,23 +163,18 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
       newPatternId = t.memberExpression(parentId, t.literal(i), true);
     }
 
-    push(opts, nodes, elem, newPatternId);
+    this.push(elem, newPatternId);
   }
 };
 
-var pushPattern = function (opts) {
-  var nodes = opts.nodes;
-  var pattern = opts.pattern;
-  var parentId = opts.id;
-  var scope = opts.scope;
-
+Destructuring.prototype.init = function (pattern, parentId) {
   if (!t.isArrayExpression(parentId) && !t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
-    var key = scope.generateUidBasedOnNode(parentId);
-    nodes.push(buildVariableDeclar(opts, key, parentId));
+    var key = this.scope.generateUidBasedOnNode(parentId);
+    this.nodes.push(this.buildVariableDeclaration(key, parentId));
     parentId = key;
   }
 
-  push(opts, nodes, pattern, parentId);
+  this.push(pattern, parentId);
 };
 
 exports.ForInStatement =
@@ -173,11 +192,14 @@ exports.ForOfStatement = function (node, parent, scope, context, file) {
 
   var nodes = [];
 
-  push({
+  var destructuring = new Destructuring({
     kind: declar.kind,
     file: file,
-    scope: scope
-  }, nodes, pattern, key);
+    scope: scope,
+    nodes: nodes
+  });
+
+  destructuring.init(pattern, key);
 
   t.ensureBlock(node);
 
@@ -196,15 +218,14 @@ exports.Function = function (node, parent, scope, context, file) {
     hasDestructuring = true;
     var parentId = scope.generateUidIdentifier("ref");
 
-    pushPattern({
+    var destructuring = new Destructuring({
       blockHoist: node.params.length - i,
-      pattern:    pattern,
       nodes:      nodes,
       scope:      scope,
       file:       file,
       kind:       "var",
-      id:         parentId
     });
+    destructuring.init(pattern, parentId);
 
     return parentId;
   });
@@ -226,11 +247,13 @@ exports.CatchClause = function (node, parent, scope, context, file) {
 
   var nodes = [];
 
-  push({
+  var destructuring = new Destructuring({
     kind: "var",
     file: file,
-    scope: scope
-  }, nodes, pattern, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(pattern, ref);
 
   node.body.body = nodes.concat(node.body.body);
 };
@@ -248,11 +271,13 @@ exports.ExpressionStatement = function (node, parent, scope, context, file) {
     t.variableDeclarator(ref, expr.right)
   ]));
 
-  push({
+  var destructuring = new Destructuring({
     operator: expr.operator,
     file: file,
-    scope: scope
-  }, nodes, expr.left, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(expr.left, ref);
 
   return nodes;
 };
@@ -269,50 +294,50 @@ exports.AssignmentExpression = function (node, parent, scope, context, file) {
   var nodes = [];
   nodes.push(t.assignmentExpression("=", ref, node.right));
 
-  push({
+  var destructuring = new Destructuring({
     operator: node.operator,
     file: file,
-    scope: scope
-  }, nodes, node.left, ref);
+    scope: scope,
+    nodes: nodes
+  });
+  destructuring.init(node.left, ref);
 
   nodes.push(ref);
 
   return t.toSequenceExpression(nodes, scope);
 };
 
-exports.VariableDeclaration = function (node, parent, scope, context, file) {
-  if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
-
-  var nodes = [];
-  var i;
-  var declar;
-
-  var hasPattern = false;
-  for (i = 0; i < node.declarations.length; i++) {
-    declar = node.declarations[i];
-    if (t.isPattern(declar.id)) {
-      hasPattern = true;
-      break;
+var variableDeclarationhasPattern = function (node) {
+  for (var i = 0; i < node.declarations.length; i++) {
+    if (t.isPattern(node.declarations[i].id)) {
+      return true;
     }
   }
-  if (!hasPattern) return;
+  return false;
+};
 
-  for (i = 0; i < node.declarations.length; i++) {
+exports.VariableDeclaration = function (node, parent, scope, context, file) {
+  if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
+  if (!variableDeclarationhasPattern(node)) return;
+
+  var nodes = [];
+  var declar;
+
+  for (var i = 0; i < node.declarations.length; i++) {
     declar = node.declarations[i];
 
     var patternId = declar.init;
     var pattern   = declar.id;
-    var opts = {
-      pattern: pattern,
-      nodes:   nodes,
-      scope:   scope,
-      kind:    node.kind,
-      file:    file,
-      id:      patternId,
-    };
+
+    var destructuring = new Destructuring({
+      nodes: nodes,
+      scope: scope,
+      kind:  node.kind,
+      file:  file
+    });
 
     if (t.isPattern(pattern) && patternId) {
-      pushPattern(opts);
+      destructuring.init(pattern, patternId);
 
       if (+i !== node.declarations.length - 1) {
         // we aren't the last declarator so let's just make the
@@ -320,11 +345,14 @@ exports.VariableDeclaration = function (node, parent, scope, context, file) {
         t.inherits(nodes[nodes.length - 1], declar);
       }
     } else {
-      nodes.push(t.inherits(buildVariableAssign(opts, declar.id, declar.init), declar));
+      nodes.push(t.inherits(destructuring.buildVariableAssignment(declar.id, declar.init), declar));
     }
   }
 
   if (!t.isProgram(parent) && !t.isBlockStatement(parent)) {
+    // https://github.com/6to5/6to5/issues/113
+    // for (let [x] = [0]; false;) {}
+
     declar = null;
 
     for (i = 0; i < nodes.length; i++) {

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

@@ -3,6 +3,8 @@
 var util = require("../../../util");
 var t    = require("../../../types");
 
+exports.check = t.isForOfStatement;
+
 exports.ForOfStatement = function (node, parent, scope, context, file) {
   var callback = spec;
   if (file.isLoose("es6.forOf")) callback = loose;

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

@@ -2,6 +2,8 @@
 
 var t = require("../../../types");
 
+exports.check = require("../internal/modules").check;
+
 exports.ImportDeclaration = function (node, parent, scope, context, file) {
   var nodes = [];
 

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

@@ -1,8 +1,11 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var util     = require("../../../util");
-var t        = require("../../../types");
+var util = require("../../../util");
+var t    = require("../../../types");
+
+exports.check = function (node) {
+  return t.isFunction(node) && hasDefaults(node);
+};
 
 var hasDefaults = function (node) {
   for (var i = 0; i < node.params.length; i++) {
@@ -51,7 +54,7 @@ exports.Function = function (node, parent, scope) {
       if (t.isIdentifier(right) && scope.hasOwnReference(right.name)) {
         state.iife = true;
       } else {
-        traverse(right, iifeVisitor, scope, state);
+        scope.traverse(right, iifeVisitor, state);
       }
     }
 

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

@@ -3,6 +3,8 @@
 var util = require("../../../util");
 var t    = require("../../../types");
 
+exports.check = t.isRestElement;
+
 var hasRest = function (node) {
   return t.isRestElement(node.params[node.params.length - 1]);
 };

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

@@ -2,6 +2,10 @@
 
 var t = require("../../../types");
 
+exports.check = function (node) {
+  return t.isProperty(node) && node.computed;
+};
+
 exports.ObjectExpression = function (node, parent, scope, context, file) {
   var hasComputed = false;
 

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

@@ -4,6 +4,10 @@ var nameMethod = require("../../helpers/name-method");
 var t          = require("../../../types");
 var clone      = require("lodash/lang/clone");
 
+exports.check = function (node) {
+  return t.isProperty(node) && (node.method || node.shorthand);
+};
+
 exports.Property = function (node, parent, scope, context, file) {
   if (node.method) {
     node.method = false;

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

@@ -1,7 +1,9 @@
 "use strict";
 
-var t = require("../../../types");
 var contains = require("lodash/collection/contains");
+var t        = require("../../../types");
+
+exports.check = t.isSpreadElement;
 
 var getSpreadLiteral = function (spread, file) {
   return file.toArray(spread.argument);

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

@@ -6,6 +6,10 @@ var buildBinaryExpression = function (left, right) {
   return t.binaryExpression("+", left, right);
 };
 
+exports.check = function (node) {
+  return t.isTemplateLiteral(node) || t.isTaggedTemplateExpression(node);
+};
+
 exports.TaggedTemplateExpression = function (node, parent, scope, context, file) {
   var args = [];
   var quasi = node.quasi;

lib/6to5/transformation/transformers/es6/unicode-regex.js

@@ -2,6 +2,11 @@
 
 var rewritePattern = require("regexpu/rewrite-pattern");
 var pull           = require("lodash/array/pull");
+var t              = require("../../../types");
+
+exports.check = function (node) {
+  return t.isLiteral(node) && node.regex && node.regex.flags.indexOf("u") >= 0;
+};
 
 exports.Literal = function (node) {
   var regex = node.regex;

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

@@ -6,18 +6,21 @@ var t = require("../../../types");
 
 exports.experimental = true;
 
-exports.ObjectExpression = function (node, parent, scope, context, file) {
-  var hasSpread = false;
-  var i;
-  var prop;
-  for (i = 0; i < node.properties.length; i++) {
-    prop = node.properties[i];
-    if (t.isSpreadProperty(prop)) {
-      hasSpread = true;
-      break;
+exports.manipulateOptions = function (opts) {
+  if (opts.whitelist.length) opts.whitelist.push("es6.destructuring");
+};
+
+var hasSpread = function (node) {
+  for (var i = 0; i < node.properties.length; i++) {
+    if (t.isSpreadProperty(node.properties[i])) {
+      return true;
     }
   }
-  if (!hasSpread) return;
+  return false;
+};
+
+exports.ObjectExpression = function (node, parent, scope, context, file) {
+  if (!hasSpread(node)) return;
 
   var args = [];
   var props = [];
@@ -28,8 +31,8 @@ exports.ObjectExpression = function (node, parent, scope, context, file) {
     props = [];
   };
 
-  for (i = 0; i < node.properties.length; i++) {
-    prop = node.properties[i];
+  for (var i = 0; i < node.properties.length; i++) {
+    var prop = node.properties[i];
     if (t.isSpreadProperty(prop)) {
       push();
       args.push(prop.argument);

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

@@ -27,7 +27,7 @@ module.exports = {
   asyncToGenerator:                        require("./other/async-to-generator"),
   bluebirdCoroutines:                      require("./other/bluebird-coroutines"),
 
-  "es7.objectSpread":                      require("./es7/object-spread"),
+  "es7.objectRestSpread":                  require("./es7/object-rest-spread"),
   "es7.exponentiationOperator":            require("./es7/exponentiation-operator"),
   "es6.spread":                            require("./es6/spread"),
   "es6.templateLiterals":                  require("./es6/template-literals"),

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

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 var functionChildrenVisitor = {
   enter: function (node, parent, scope, context, state) {
@@ -37,7 +36,7 @@ var functionVisitor = {
     }
 
     // traverse all child nodes of this function and find `arguments` and `this`
-    traverse(node, functionChildrenVisitor, scope, state);
+    scope.traverse(node, functionChildrenVisitor, state);
 
     return context.skip();
   }
@@ -58,7 +57,7 @@ var go = function (getBody, node, scope) {
 
   // traverse the function and find all alias functions so we can alias
   // `arguments` and `this` if necessary
-  traverse(node, functionVisitor, scope, state);
+  scope.traverse(node, functionVisitor, state);
 
   var body;
 

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

@@ -15,6 +15,10 @@ var resolveModuleSource = function (node, parent, scope, context, file) {
   }
 };
 
+exports.check = function (node) {
+  return t.isImportDeclaration(node) || t.isExportDeclaration(node);
+};
+
 exports.ImportDeclaration = resolveModuleSource;
 
 exports.ExportDeclaration = function (node, parent, scope) {

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

@@ -5,9 +5,16 @@
 
 // jsx
 
-var esutils = require("esutils");
-var react   = require("../../helpers/react");
-var t       = require("../../../types");
+var isString = require("lodash/lang/isString");
+var esutils  = require("esutils");
+var react    = require("../../helpers/react");
+var t        = require("../../../types");
+
+exports.check = function (node) {
+  if (t.isJSX(node)) return true;
+  if (react.isCreateClass(node)) return true;
+  return false;
+};
 
 exports.JSXIdentifier = function (node, parent) {
   if (node.name === "this" && t.isReferenced(node, parent)) {
@@ -160,6 +167,8 @@ exports.JSXElement = {
       callExpr.arguments.push(child);
     }
 
+    callExpr.arguments = flatten(callExpr.arguments);
+
     if (callExpr.arguments.length >= 3) {
       callExpr._prettyCall = true;
     }
@@ -168,6 +177,27 @@ exports.JSXElement = {
   }
 };
 
+var isStringLiteral = function (node) {
+  return t.isLiteral(node) && isString(node.value);
+};
+
+var flatten = function (args) {
+  var flattened = [];
+  var last;
+
+  for (var i = 0; i < args.length; i++) {
+    var arg = args[i];
+    if (isStringLiteral(arg) && isStringLiteral(last)) {
+      last.value += arg.value;
+    } else {
+      last = arg;
+      flattened.push(arg);
+    }
+  }
+
+  return flattened;
+};
+
 var cleanJSXElementLiteralChild = function (child, args) {
   var lines = child.value.split(/\r\n|\n|\r/);
 

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

@@ -1,6 +1,11 @@
 "use strict";
 
 var regenerator = require("regenerator-6to5");
+var t           = require("../../../types");
+
+exports.check = function (node) {
+  return t.isFunction(node) && (node.async || node.generator);
+};
 
 exports.ast = {
   before: function (ast, file) {

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

@@ -1,6 +1,5 @@
 "use strict";
 
-var traverse = require("../../../traverse");
 var util     = require("../../../util");
 var core     = require("core-js/library");
 var t        = require("../../../types");
@@ -77,7 +76,7 @@ exports.ast = {
   },
 
   after: function (ast, file) {
-    traverse(ast, astVisitor, null, file);
+    file.scope.traverse(ast, astVisitor, file);
   }
 };
 

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

@@ -1,7 +1,6 @@
 "use strict";
 
-var traverse = require("../../../traverse");
-var t        = require("../../../types");
+var t = require("../../../types");
 
 exports.playground = true;
 
@@ -23,6 +22,7 @@ exports.Property =
 exports.MethodDefinition = function (node, parent, scope, context, file) {
   if (node.kind !== "memo") return;
   node.kind = "get";
+  file.checkNode(node, scope);
 
   var value = node.value;
   t.ensureBlock(value);
@@ -38,5 +38,5 @@ exports.MethodDefinition = function (node, parent, scope, context, file) {
     file: file
   };
 
-  traverse(value, visitor, scope, state);
+  scope.traverse(value, visitor, state);
 };

lib/6to5/traverse/index.js

@@ -10,11 +10,12 @@ var contains = require("lodash/collection/contains");
 var flatten  = require("lodash/array/flatten");
 var compact  = require("lodash/array/compact");
 
-function TraversalContext() {
+function TraversalContext(scope) {
   this.shouldFlatten = false;
   this.shouldRemove  = false;
   this.shouldSkip    = false;
   this.shouldStop    = false;
+  this.scope         = scope;
 }
 
 TraversalContext.prototype.flatten = function () {
@@ -44,20 +45,31 @@ TraversalContext.prototype.reset = function () {
 TraversalContext.prototype.maybeRemove = function (obj, key) {
   if (this.shouldRemove) {
     obj[key] = null;
-    this.shouldFlatten = true;
+    this.flatten();
   }
 };
 
-function replaceNode(obj, key, node, result) {
-  var isArray = Array.isArray(result);
+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 = result;
-  if (isArray) inheritTo = result[0];
+  var inheritTo = replacement;
+  if (isArray) inheritTo = replacement[0];
   if (inheritTo) t.inheritsComments(inheritTo, node);
 
   // replace the node
-  obj[key] = result;
+  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
@@ -66,39 +78,16 @@ function replaceNode(obj, key, node, result) {
   }
 
   if (isArray) {
-    return true;
+    this.flatten();
   }
-}
-
-TraversalContext.prototype.enterNode = function (obj, key, node, enter, parent, scope, state) {
-  var result = enter(node, parent, scope, this, state);
-  var flatten = false;
-
-  if (result) {
-    flatten = replaceNode(obj, key, node, result);
-    node = result;
-
-    if (flatten) {
-      this.shouldFlatten = true;
-    }
-  }
-
-  this.maybeRemove(obj, key);
-
-  return node;
 };
 
-TraversalContext.prototype.exitNode = function (obj, key, node, exit, parent, scope, state) {
-  var result = exit(node, parent, scope, this, state);
-  var flatten = false;
+TraversalContext.prototype.call = function (fn, obj, key, node, parent, scope, state) {
+  var replacement = fn(node, parent, scope, this, state);
 
-  if (result) {
-    flatten = replaceNode(obj, key, node, result);
-    node = result;
-
-    if (flatten) {
-      this.shouldFlatten = true;
-    }
+  if (replacement) {
+    this.replaceNode(obj, key, node, replacement, scope);
+    node = replacement;
   }
 
   this.maybeRemove(obj, key);
@@ -122,7 +111,7 @@ TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent,
     ourScope = new Scope(node, parent, scope);
   }
 
-  node = this.enterNode(obj, key, node, opts.enter, parent, ourScope, state);
+  node = this.call(opts.enter, obj, key, node, parent, ourScope, state);
 
   if (this.shouldSkip) {
     return this.shouldStop;
@@ -136,7 +125,7 @@ TraversalContext.prototype.visitNode = function (obj, key, opts, scope, parent,
     }
   } else {
     traverseNode(node, opts, ourScope, state);
-    this.exitNode(obj, key, node, opts.exit, parent, ourScope, state);
+    this.call(opts.exit, obj, key, node, parent, ourScope, state);
   }
 
   return this.shouldStop;
@@ -174,7 +163,7 @@ function traverseNode(node, opts, scope, state) {
   var keys = t.VISITOR_KEYS[node.type];
   if (!keys) return;
 
-  var context = new TraversalContext();
+  var context = new TraversalContext(scope);
   for (var i = 0; i < keys.length; i++) {
     if (context.visit(node, keys[i], opts, scope, state)) {
       return;

lib/6to5/traverse/scope.js

@@ -35,6 +35,18 @@ function Scope(block, parentBlock, parent, file) {
 
 Scope.defaultDeclarations = flatten([globals.builtin, globals.browser, globals.node].map(Object.keys));
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} opts
+ * @param [state]
+ */
+
+Scope.prototype.traverse = function (node, opts, state) {
+  traverse(node, opts, this, state);
+};
+
 /**
  * Description
  *
@@ -296,7 +308,7 @@ Scope.prototype.crawl = function () {
   // Program, BlockStatement - let variables
 
   if (t.isBlockStatement(block) || t.isProgram(block)) {
-    traverse(block, blockVariableVisitor, this, this);
+    this.traverse(block, blockVariableVisitor, this);
   }
 
   // CatchClause - param
@@ -322,7 +334,7 @@ Scope.prototype.crawl = function () {
   // Program, Function - var variables
 
   if (t.isProgram(block) || t.isFunction(block)) {
-    traverse(block, functionVariableVisitor, this, {
+    this.traverse(block, functionVariableVisitor, {
       blockId: block.id,
       scope:   this
     });
@@ -339,7 +351,7 @@ Scope.prototype.crawl = function () {
   // Program
 
   if (t.isProgram(block)) {
-    traverse(block, programReferenceVisitor, this, this);
+    this.traverse(block, programReferenceVisitor, this);
   }
 };
 

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

@@ -44,28 +44,39 @@
   "ArrayPattern":      ["Pattern"],
   "AssignmentPattern": ["Pattern"],
 
-  "Property": ["UserWhitespacable"],
+  "Property":   ["UserWhitespacable"],
   "JSXElement": ["UserWhitespacable", "Expression"],
 
-  "ArrayExpression": ["Expression"],
-  "AssignmentExpression": ["Expression"],
-  "AwaitExpression": ["Expression"],
-  "BindFunctionExpression": ["Expression"],
-  "BindMemberExpression": ["Expression"],
-  "CallExpression": ["Expression"],
-  "ComprehensionExpression": ["Expression", "Scope"],
-  "ConditionalExpression": ["Expression"],
-  "Identifier": ["Expression"],
-  "Literal": ["Expression"],
-  "MemberExpression": ["Expression"],
-  "NewExpression": ["Expression"],
-  "ObjectExpression": ["Expression"],
-  "SequenceExpression": ["Expression"],
-  "TaggedTemplateExpression": ["Expression"],
-  "ThisExpression": ["Expression"],
-  "UpdateExpression": ["Expression"],
+  "ArrayExpression":           ["Expression"],
+  "AssignmentExpression":      ["Expression"],
+  "AwaitExpression":           ["Expression"],
+  "BindFunctionExpression":    ["Expression"],
+  "BindMemberExpression":      ["Expression"],
+  "CallExpression":            ["Expression"],
+  "ComprehensionExpression":   ["Expression", "Scope"],
+  "ConditionalExpression":     ["Expression"],
+  "Identifier":                ["Expression"],
+  "Literal":                   ["Expression"],
+  "MemberExpression":          ["Expression"],
+  "NewExpression":             ["Expression"],
+  "ObjectExpression":          ["Expression"],
+  "SequenceExpression":        ["Expression"],
+  "TaggedTemplateExpression":  ["Expression"],
+  "ThisExpression":            ["Expression"],
+  "UpdateExpression":          ["Expression"],
   "VirtualPropertyExpression": ["Expression"],
-  "JSXEmptyExpression": ["Expression"],
-  "JSXMemberExpression": ["Expression"],
-  "YieldExpression": ["Expression"]
+  "JSXEmptyExpression":        ["Expression"],
+  "JSXMemberExpression":       ["Expression"],
+  "YieldExpression":           ["Expression"],
+
+  "JSXAttribute":           ["JSX"],
+  "JSXClosingElement":      ["JSX"],
+  "JSXElement":             ["JSX"],
+  "JSXEmptyExpression":     ["JSX"],
+  "JSXExpressionContainer": ["JSX"],
+  "JSXIdentifier":          ["JSX"],
+  "JSXMemberExpression":    ["JSX"],
+  "JSXNamespacedName":      ["JSX"],
+  "JSXOpeningElement":      ["JSX"],
+  "JSXSpreadAttribute":     ["JSX"]
 }

lib/6to5/util.js

@@ -138,7 +138,7 @@ exports.parse = function (opts, code, callback) {
 
     var ast = acorn.parse(code, {
       allowImportExportEverywhere: opts.allowImportExportEverywhere,
-      allowReturnOutsideFunction:  true,
+      allowReturnOutsideFunction:  !opts._anal,
       ecmaVersion:                 opts.experimental ? 7 : 6,
       playground:                  opts.playground,
       strictMode:                  opts.strictMode,

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "3.3.8",
+  "version": "3.3.10",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://6to5.org/",
   "repository": "6to5/6to5",

packages/6to5-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5-runtime",
   "description": "6to5 selfContained runtime",
-  "version": "3.3.7",
+  "version": "3.3.9",
   "repository": "6to5/6to5",
   "author": "Sebastian McKenzie <sebmck@gmail.com>"
 }

test/_helper.js

@@ -1,7 +1,8 @@
-var util = require("../lib/6to5/util");
-var path = require("path");
-var fs   = require("fs");
-var _    = require("lodash");
+var esvalid = require("esvalid");
+var util    = require("../lib/6to5/util");
+var path    = require("path");
+var fs      = require("fs");
+var _       = require("lodash");
 
 var humanize = function (val, noext) {
   if (noext) val = path.basename(val, path.extname(val));
@@ -18,6 +19,17 @@ var readFile = exports.readFile = function (filename) {
   }
 };
 
+exports.esvalid = function (ast, loc) {
+  var errors = esvalid.errors(ast);
+  if (errors.length) {
+    var msg = [];
+    _.each(errors, function (err) {
+      msg.push(err.message + " - " + JSON.stringify(err.node));
+    });
+    throw new Error(loc + ": " + msg.join(". "));
+  }
+};
+
 exports.assertVendor = function (name) {
   if (!fs.existsSync(__dirname + "/../vendor/" + name)) {
     console.error("No vendor/" + name + " - run `make bootstrap`");

test/_transformation-helper.js

@@ -2,7 +2,6 @@ var genHelpers = require("./_generator-helpers");
 var transform  = require("../lib/6to5/transformation");
 var sourceMap  = require("source-map");
 var codeFrame  = require("../lib/6to5/helpers/code-frame");
-var esvalid    = require("esvalid");
 var Module     = require("module");
 var helper     = require("./_helper");
 var assert     = require("assert");
@@ -55,15 +54,7 @@ var run = function (task, done) {
 
   var checkAst = function (result, opts) {
     if (noCheckAst) return;
-
-    var errors = esvalid.errors(result.ast.program);
-    if (errors.length) {
-      var msg = [];
-      _.each(errors, function (err) {
-        msg.push(err.message + " - " + JSON.stringify(err.node));
-      });
-      throw new Error(opts.loc + ": " + msg.join(". "));
-    }
+    helper.esvalid(result.ast.program, opts.loc);
   };
 
   if (execCode) {

test/fixtures/bin/6to5/dir --out-dir --source-maps-inline/out-files/lib/bar/bar.js

@@ -5,4 +5,4 @@ var _classCallCheck = function (instance, Constructor) { if (!(instance instance
 var Test = function Test() {
   _classCallCheck(this, Test);
 };
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9iYXIvYmFyLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7Ozs7SUFBTSxnQkFBQTt3QkFBQSIsImZpbGUiOiJzcmMvYmFyL2Jhci5qcyIsInNvdXJjZXNDb250ZW50IjpbImNsYXNzIFRlc3Qge1xuXG59Il19
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9iYXIvYmFyLmpzIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7Ozs7SUFBTSxJQUFJLFlBQUosSUFBSTt3QkFBSixJQUFJIiwiZmlsZSI6InNyYy9iYXIvYmFyLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iXX0=

test/fixtures/bin/6to5/dir --out-dir --source-maps-inline/out-files/lib/foo.js

@@ -3,4 +3,4 @@
 arr.map(function (x) {
   return x * MULTIPLIER;
 });
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9mb28uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxJQUFJLElBQUksVUFBQTtTQUFLLElBQUkiLCJmaWxlIjoic3JjL2Zvby5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogTVVMVElQTElFUik7Il19
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNyYy9mb28uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxHQUFHLENBQUMsR0FBRyxDQUFDLFVBQUEsQ0FBQztTQUFJLENBQUMsR0FBRyxVQUFVO0NBQUEsQ0FBQyxDQUFDIiwiZmlsZSI6InNyYy9mb28uanMiLCJzb3VyY2VzQ29udGVudCI6WyJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==

test/fixtures/bin/6to5/dir --out-dir --source-maps/out-files/lib/bar/bar.js.map

@@ -1 +1 @@
-{"version":3,"sources":["src/bar/bar.js"],"names":[],"mappings":";;;;IAAM,gBAAA;wBAAA","file":"src/bar/bar.js","sourcesContent":["class Test {\n\n}"]}
+{"version":3,"sources":["src/bar/bar.js"],"names":[],"mappings":";;;;IAAM,IAAI,YAAJ,IAAI;wBAAJ,IAAI","file":"src/bar/bar.js","sourcesContent":["class Test {\n\n}"]}

test/fixtures/bin/6to5/dir --out-dir --source-maps/out-files/lib/foo.js.map

@@ -1 +1 @@
-{"version":3,"sources":["src/foo.js"],"names":[],"mappings":";;AAAA,IAAI,IAAI,UAAA;SAAK,IAAI","file":"src/foo.js","sourcesContent":["arr.map(x => x * MULTIPLIER);"]}
+{"version":3,"sources":["src/foo.js"],"names":[],"mappings":";;AAAA,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,UAAU;CAAA,CAAC,CAAC","file":"src/foo.js","sourcesContent":["arr.map(x => x * MULTIPLIER);"]}

test/fixtures/bin/6to5/filename --out-file --source-maps-inline/out-files/script2.js

@@ -4,4 +4,4 @@ arr.map(function (x) {
   return x * MULTIPLIER;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiOztBQUFBLElBQUksSUFBSSxVQUFBO1NBQUssSUFBSSIsImZpbGUiOiJzY3JpcHQyLmpzIiwic291cmNlc0NvbnRlbnQiOlsiYXJyLm1hcCh4ID0+IHggKiBNVUxUSVBMSUVSKTsiXX0=
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiOztBQUFBLEdBQUcsQ0FBQyxHQUFHLENBQUMsVUFBQSxDQUFDO1NBQUksQ0FBQyxHQUFHLFVBQVU7Q0FBQSxDQUFDLENBQUMiLCJmaWxlIjoic2NyaXB0Mi5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogTVVMVElQTElFUik7Il19

test/fixtures/bin/6to5/filenames --out-file --source-maps-inline/out-files/script3.js

@@ -11,4 +11,4 @@ arr.map(function (x) {
   return x * MULTIPLIER;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyIsInNjcmlwdDIuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7OztJQUFNLGdCQUFBO3dCQUFBOzs7OztBQ0FOLElBQUksSUFBSSxVQUFBO1NBQUssSUFBSSIsImZpbGUiOiJzY3JpcHQzLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iLCJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNjcmlwdC5qcyIsInNjcmlwdDIuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7OztJQUFNLElBQUksWUFBSixJQUFJO3dCQUFKLElBQUk7Ozs7O0FDQVYsR0FBRyxDQUFDLEdBQUcsQ0FBQyxVQUFBLENBQUM7U0FBSSxDQUFDLEdBQUcsVUFBVTtDQUFBLENBQUMsQ0FBQyIsImZpbGUiOiJzY3JpcHQzLmpzIiwic291cmNlc0NvbnRlbnQiOlsiY2xhc3MgVGVzdCB7XG5cbn0iLCJhcnIubWFwKHggPT4geCAqIE1VTFRJUExJRVIpOyJdfQ==

test/fixtures/bin/6to5/filenames --out-file --source-maps/out-files/script3.js.map

@@ -1 +1 @@
-{"version":3,"sources":["script.js","script2.js"],"names":[],"mappings":";;;;IAAM,gBAAA;wBAAA;;;;;ACAN,IAAI,IAAI,UAAA;SAAK,IAAI","file":"script3.js","sourcesContent":["class Test {\n\n}","arr.map(x => x * MULTIPLIER);"]}
+{"version":3,"sources":["script.js","script2.js"],"names":[],"mappings":";;;;IAAM,IAAI,YAAJ,IAAI;wBAAJ,IAAI;;;;;ACAV,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,UAAU;CAAA,CAAC,CAAC","file":"script3.js","sourcesContent":["class Test {\n\n}","arr.map(x => x * MULTIPLIER);"]}

test/fixtures/bin/6to5/stdin --out-file --source-maps/out-files/test.js.map

@@ -1 +1 @@
-{"version":3,"sources":["stdin"],"names":[],"mappings":";;AAAA,IAAI,IAAI,UAAA;SAAK,IAAI","file":"test.js","sourcesContent":["arr.map(x => x * x);"]}
+{"version":3,"sources":["stdin"],"names":[],"mappings":";;AAAA,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,CAAC;CAAA,CAAC,CAAC","file":"test.js","sourcesContent":["arr.map(x => x * x);"]}

test/fixtures/bin/6to5/stdin --source-maps-inline/stdout.txt

@@ -4,4 +4,4 @@ arr.map(function (x) {
   return x * x;
 });
 
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7O0FBQUEsSUFBSSxJQUFJLFVBQUE7U0FBSyxJQUFJIiwiZmlsZSI6InN0ZG91dCIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogeCk7Il19
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7O0FBQUEsR0FBRyxDQUFDLEdBQUcsQ0FBQyxVQUFBLENBQUM7U0FBSSxDQUFDLEdBQUcsQ0FBQztDQUFBLENBQUMsQ0FBQyIsImZpbGUiOiJzdGRvdXQiLCJzb3VyY2VzQ29udGVudCI6WyJhcnIubWFwKHggPT4geCAqIHgpOyJdfQ==

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

@@ -1,21 +0,0 @@
-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(Object.getPrototypeOf(Test.prototype), "constructor", this).call(this);
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
+    _get(Foo.prototype, "constructor", this).call(this);
+    _get(Foo.prototype, "test", this).call(this);
 
-    _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, "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), "test", this).apply(this, arguments);
-    (_get3 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get3, [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)));
   }
 
   _inherits(Test, Foo);
@@ -31,9 +31,9 @@ var Test = (function (Foo) {
     foo: {
       value: function foo() {
         var _get2;
-        _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)));
+        _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)));
       },
       writable: true,
       configurable: true
@@ -42,9 +42,9 @@ var Test = (function (Foo) {
     test: {
       value: function test() {
         var _get2;
-        _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)));
+        _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)));
       },
       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(Object.getPrototypeOf(Test.prototype), "test", this);
-    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever;
+    _get(Foo.prototype, "test", this);
+    _get(Foo.prototype, "test", this).whatever;
   }
 
   _inherits(Test, Foo);

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

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

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

@@ -8,8 +8,8 @@ var BaseController = (function (_Chaplin$Controller) {
   function BaseController() {
     _classCallCheck(this, BaseController);
 
-    if (Object.getPrototypeOf(BaseController) !== null) {
-      Object.getPrototypeOf(BaseController).apply(this, arguments);
+    if (_Chaplin$Controller != null) {
+      _Chaplin$Controller.apply(this, arguments);
     }
   }
 
@@ -22,12 +22,12 @@ var BaseController2 = (function (_Chaplin$Controller$Another) {
   function BaseController2() {
     _classCallCheck(this, BaseController2);
 
-    if (Object.getPrototypeOf(BaseController2) !== null) {
-      Object.getPrototypeOf(BaseController2).apply(this, arguments);
+    if (_Chaplin$Controller$Another != null) {
+      _Chaplin$Controller$Another.apply(this, arguments);
     }
   }
 
   _inherits(BaseController2, _Chaplin$Controller$Another);
 
   return BaseController2;
-})(Chaplin.Controller.Another);
+})(Chaplin.Controller.Another);

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

@@ -8,12 +8,12 @@ var Test = (function (Foo) {
   function Test() {
     _classCallCheck(this, Test);
 
-    if (Object.getPrototypeOf(Test) !== null) {
-      Object.getPrototypeOf(Test).apply(this, arguments);
+    if (Foo != null) {
+      Foo.apply(this, arguments);
     }
   }
 
   _inherits(Test, Foo);
 
   return Test;
-})(Foo);
+})(Foo);

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(Object.getPrototypeOf(Test.prototype), "hasOwnProperty", this).call(this, "test");
-};
+  _get(Function.prototype, "hasOwnProperty", this).call(this, "test");
+};

test/fixtures/transformation/es6-destructuring/empty-object-pattern/actual.js

@@ -0,0 +1 @@
+var {} = null;

test/fixtures/transformation/es6-destructuring/empty-object-pattern/exec.js

@@ -0,0 +1,3 @@
+assert.throws(function () {
+  var {} = null;
+}, /Cannot destructure undefined/);

test/fixtures/transformation/es6-destructuring/empty-object-pattern/expected.js

@@ -0,0 +1,7 @@
+"use strict";
+
+var _objectDestructuringEmpty = function (obj) { if (obj == null) throw new TypeError("Cannot destructure undefined"); };
+
+var _ref = null;
+
+_objectDestructuringEmpty(_ref);

test/fixtures/transformation/react/concatenates-adjacent-string-literals/actual.js

@@ -0,0 +1,13 @@
+var x =
+  <div>
+    foo
+    {'bar'}
+    baz
+    <div>
+      buz
+      bang
+    </div>
+    qux
+    {null}
+    quack
+  </div>

test/fixtures/transformation/react/concatenates-adjacent-string-literals/expected.js

@@ -0,0 +1,13 @@
+var x = React.createElement(
+  "div",
+  null,
+  "foobarbaz",
+  React.createElement(
+    "div",
+    null,
+    "buz bang"
+  ),
+  "qux",
+  null,
+  "quack"
+);

test/fixtures/transformation/source-maps/arrow-function/source-mappings.json

@@ -1,7 +1,7 @@
 [{
   "original": {
     "line": 1,
-    "column": 13
+    "column": 14
   },
   "generated": {
     "line": 4,

test/fixtures/transformation/source-maps/full/source-map.json

@@ -3,6 +3,6 @@
   "file": "source-maps/full/expected.js",
   "sources": ["source-maps/full/actual.js"],
   "names": [],
-  "mappings": ";;AAAA,IAAI,IAAI,UAAA;SAAK,IAAI",
+  "mappings": ";;AAAA,GAAG,CAAC,GAAG,CAAC,UAAA,CAAC;SAAI,CAAC,GAAG,CAAC;CAAA,CAAC,CAAC",
   "sourcesContent": ["arr.map(x => x * x);"]
 }

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

@@ -3,4 +3,4 @@
 arr.map(function (x) {
   return x * x;
 });
-//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNvdXJjZS1tYXBzL2lubGluZS9hY3R1YWwuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxJQUFJLElBQUksVUFBQTtTQUFLLElBQUkiLCJmaWxlIjoic291cmNlLW1hcHMvaW5saW5lL2V4cGVjdGVkLmpzIiwic291cmNlc0NvbnRlbnQiOlsiYXJyLm1hcCh4ID0+IHggKiB4KTsiXX0=
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInNvdXJjZS1tYXBzL2lubGluZS9hY3R1YWwuanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6Ijs7QUFBQSxHQUFHLENBQUMsR0FBRyxDQUFDLFVBQUEsQ0FBQztTQUFJLENBQUMsR0FBRyxDQUFDO0NBQUEsQ0FBQyxDQUFDIiwiZmlsZSI6InNvdXJjZS1tYXBzL2lubGluZS9leHBlY3RlZC5qcyIsInNvdXJjZXNDb250ZW50IjpbImFyci5tYXAoeCA9PiB4ICogeCk7Il19

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

@@ -10,12 +10,12 @@ var Foo = (function (Bar) {
   function Foo() {
     _classCallCheck(this, Foo);
 
-    if (Object.getPrototypeOf(Foo) !== null) {
-      Object.getPrototypeOf(Foo).apply(this, arguments);
+    if (Bar != null) {
+      Bar.apply(this, arguments);
     }
   }
 
   _inherits(Foo, Bar);
 
   return Foo;
-})(Bar);
+})(Bar);

test/test262.js

@@ -4,6 +4,7 @@ require("./_helper").assertVendor("test262");
 
 var transform = require("../lib/6to5/transformation");
 var readdir   = require("fs-readdir-recursive");
+var helper    = require("./_helper");
 var path      = require("path");
 var fs        = require("fs");
 var _         = require("lodash");
@@ -16,7 +17,7 @@ var read = function (loc) {
   });
 };
 
-var exec = function (loc) {
+var check = function (loc) {
   try {
     var file = fs.readFileSync(loc, "utf8");
 
@@ -26,25 +27,21 @@ var exec = function (loc) {
     // ReferenceError: 1++; (runtime)
     var lazyError = /negative: (\S+)/.test(file);
 
-    var compiled = transform(file, {
+    transform(file, {
       filename: loc,
-      blacklist: ["useStrict"]
+      blacklist: ["useStrict"],
+      _anal: true
     });
-
-    global.eval(compiled);
   } catch (err) {
     if (err && lazyError && err instanceof SyntaxError) {
       return;
     } else {
+      err.stack = loc + ": " + err.stack;
       throw err;
     }
   }
 };
 
-// harness
-var harness = read(test262Loc + "/harness");
-_.each(harness, exec);
-
 // tests!
 var tests = read(test262Loc + "/test");
 _.each(tests, function (loc) {
@@ -52,6 +49,6 @@ _.each(tests, function (loc) {
   alias = alias.replace(/\.([^\.]+)$/g, "");
   test(alias, function () {
     this.timeout(0);
-    exec(loc);
+    check(loc);
   });
 });