fix fast forOf and add tests

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

@@ -5,9 +5,10 @@ exports.ForOfStatement = function (node, parent, file, scope) {
   var callback = spec;
   if (file.isFast("forOf")) callback = fast;
 
-  var build = callback(node, parent, file, scope);
-  var loop  = build.loop;
-  var block = loop.body;
+  var build  = callback(node, parent, file, scope);
+  var declar = build.declar;
+  var loop   = build.loop;
+  var block  = loop.body;
 
   // inherit comments from the original loop
   t.inheritsComments(loop, node);
@@ -15,8 +16,14 @@ exports.ForOfStatement = function (node, parent, file, scope) {
   // ensure that it's a block so we can take all it's statemetns
   t.ensureBlock(node);
 
-  // push the value declaration to the new loop body
-  if (build.declar) block.body.push(build.declar);
+  // add the value declaration to the new loop body
+  if (declar){
+    if (build.shouldUnshift) {
+      block.body.unshift(declar);
+    } else {
+      block.body.push(declar);
+    }
+  }
 
   // push the rest of the original loop body onto our new body
   block.body = block.body.concat(node.body.body);
@@ -42,7 +49,7 @@ var fast = function (node, parent, file, scope) {
   }
 
   var loop = util.template("for-of-fast", {
-    LOOP_OBJECT:  file.generateUidIdentifier("loopObject", scope),
+    LOOP_OBJECT:  file.generateUidIdentifier("iterator", scope),
     IS_ARRAY:     file.generateUidIdentifier("isArray", scope),
     OBJECT:       node.right,
     INDEX:        file.generateUidIdentifier("i", scope),
@@ -50,8 +57,9 @@ var fast = function (node, parent, file, scope) {
   });
 
   return {
-    declar: declar,
-    loop:   loop
+    shouldUnshift: true,
+    declar:        declar,
+    loop:          loop
   };
 };
 

test/fixtures/transformation/es6-for-of-fast/identifier/actual.js

@@ -0,0 +1,3 @@
+for (i of arr) {
+
+}

test/fixtures/transformation/es6-for-of-fast/identifier/expected.js

@@ -0,0 +1,15 @@
+"use strict";
+
+for (var _iterator = arr,
+    _isArray = Array.isArray(_iterator),
+    _i = 0,
+    _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    i = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    i = _i.value;
+  }
+}

test/fixtures/transformation/es6-for-of-fast/let/actual.js

@@ -0,0 +1,3 @@
+for (let i of arr) {
+
+}

test/fixtures/transformation/es6-for-of-fast/let/expected.js

@@ -0,0 +1,16 @@
+"use strict";
+
+for (var _iterator = arr,
+    _isArray = Array.isArray(_iterator),
+    _i = 0,
+    _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  var i = undefined;
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    i = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    i = _i.value;
+  }
+}

test/fixtures/transformation/es6-for-of-fast/multiple/actual.js

@@ -0,0 +1,7 @@
+for (var i of arr) {
+
+}
+
+for (var i of numbers) {
+
+}

test/fixtures/transformation/es6-for-of-fast/multiple/expected.js

@@ -0,0 +1,31 @@
+"use strict";
+
+for (var _iterator = arr,
+    _isArray = Array.isArray(_iterator),
+    _i = 0,
+    _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  var i;
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    i = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    i = _i.value;
+  }
+}
+
+for (var _iterator2 = numbers,
+    _isArray2 = Array.isArray(_iterator2),
+    _i2 = 0,
+    _iterator2 = _isArray2 ? _iterator2 : _iterator2[Symbol.iterator]();;) {
+  var i;
+  if (_isArray2) {
+    if (_i2 >= _iterator2.length) break;
+    i = _iterator2[_i2++];
+  } else {
+    _i2 = _iterator2.next();
+    if (_i2.done) break;
+    i = _i2.value;
+  }
+}

test/fixtures/transformation/es6-for-of-fast/options.json

@@ -0,0 +1,3 @@
+{
+  "fast": ["forOf"]
+}

test/fixtures/transformation/es6-for-of-fast/var/actual.js

@@ -0,0 +1,3 @@
+for (var i of arr) {
+
+}

test/fixtures/transformation/es6-for-of-fast/var/expected.js

@@ -0,0 +1,16 @@
+"use strict";
+
+for (var _iterator = arr,
+    _isArray = Array.isArray(_iterator),
+    _i = 0,
+    _iterator = _isArray ? _iterator : _iterator[Symbol.iterator]();;) {
+  var i;
+  if (_isArray) {
+    if (_i >= _iterator.length) break;
+    i = _iterator[_i++];
+  } else {
+    _i = _iterator.next();
+    if (_i.done) break;
+    i = _i.value;
+  }
+}