change obj references to a unique identifier

lib/6to5/templates/function-return-obj-this.js

@@ -1,3 +1,3 @@
-(function (obj) {
-  return obj;
+(function (KEY) {
+  return KEY;
 }).call(this, OBJECT)

lib/6to5/templates/function-return-obj.js

@@ -1,3 +1,3 @@
-(function (obj) {
-  return obj;
+(function (KEY) {
+  return KEY;
 })(OBJECT)

lib/6to5/templates/obj-key-set.js

@@ -1 +1 @@
-obj[KEY] = VALUE;
+OBJECT_KEY[KEY] = VALUE;

lib/6to5/templates/object-define-properties-closure.js

@@ -1,4 +1,4 @@
-(function (obj) {
+(function (KEY) {
   CONTENT;
-  return obj;
+  return KEY;
 })(OBJECT);

lib/6to5/transformers/computed-property-names.js

@@ -1,8 +1,9 @@
 var traverse = require("../traverse");
 var util     = require("../util");
+var b        = require("ast-types").builders;
 var _        = require("lodash");
 
-exports.ObjectExpression = function (node) {
+exports.ObjectExpression = function (node, parent, opts, generateUid) {
   var hasComputed = false;
   var hasThis     = false;
 
@@ -24,7 +25,10 @@ exports.ObjectExpression = function (node) {
   var templateName = "function-return-obj";
   if (hasThis) templateName += "-this";
 
+  var objId = b.identifier(generateUid("ref"));
+
   var container = util.template(templateName, {
+    KEY: objId,
     OBJECT: node
   });
 
@@ -37,6 +41,7 @@ exports.ObjectExpression = function (node) {
 
   _.each(computed, function (prop) {
     containerBody.unshift(util.template("obj-key-set", {
+      OBJECT_KEY: objId,
       KEY: prop.key,
       VALUE: prop.value
     }, true));

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

@@ -22,7 +22,7 @@ exports.ForOfStatement = function (node, parent, opts, generateUid) {
   util.ensureBlock(node);
 
   var block = node2.body;
-  block.body = block.body.concat(node.body.body || []);
+  block.body = block.body.concat(node.body.body);
 
   var declar  = block.body[0];
   declar.kind = declar.kind;

lib/6to5/transformers/property-method-assignment.js

@@ -6,7 +6,7 @@ exports.Property = function (node) {
   if (node.method) node.method = false;
 };
 
-exports.ObjectExpression = function (node) {
+exports.ObjectExpression = function (node, parent, opts, generateUid) {
   var mutatorMap = {};
 
   node.properties = node.properties.filter(function (prop) {
@@ -20,8 +20,11 @@ exports.ObjectExpression = function (node) {
 
   if (_.isEmpty(mutatorMap)) return;
 
+  var objId = b.identifier(generateUid("ref"))
+
   return util.template("object-define-properties-closure", {
+    KEY: objId,
     OBJECT: node,
-    CONTENT: util.buildDefineProperties(mutatorMap, b.identifier("obj")).expression
+    CONTENT: util.buildDefineProperties(mutatorMap, objId).expression
   });
 };

lib/6to5/traverse/index.js

@@ -11,7 +11,9 @@ var traverse = module.exports = function (parent, callbacks, blacklistTypes) {
     return;
   }
 
-  var keys = VISITOR_KEYS[parent.type] || [];
+  var keys = VISITOR_KEYS[parent.type];
+  if (!keys) return;
+
   blacklistTypes = blacklistTypes || [];
 
   if (_.isFunction(callbacks)) {