v2.13.2

Remove unused local variable

.npmignore

@@ -10,3 +10,4 @@ dist
 tests.json
 CHANGELOG.md
 .package.json
+coverage

CHANGELOG.md

@@ -11,6 +11,19 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 2.13.2
+
+ * **Bug Fix**
+  * Fix `super` inside of nested functions.
+ * **Internal**
+  * Move let scoping TDZ into a separate transformer until it's more solid.
+  * Use `process.stdin.write` instead of `console.log` in `bin` to avoid sprintfification.
+
+## 2.13.1
+
+ * **New Feature**
+  * Temporal dead zone for block binding.
+
 ## 2.13.0
 
  * **New Feature**

Makefile

@@ -1,6 +1,7 @@
 BROWSERIFY_CMD = node_modules/browserify/bin/cmd.js
 ISTANBUL_CMD = node_modules/istanbul/lib/cli.js cover
-UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs --mangle sort
+UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs
+#UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs --mangle sort
 JSHINT_CMD = node_modules/jshint/bin/jshint
 MOCHA_CMD = node_modules/mocha/bin/_mocha
 

NOTES.md

@@ -11,3 +11,4 @@
  * Add autoindentation.
  * Move `super` transformation from classes into a separate transformer that also supports object expressions.
  * Remove fast transformer backwards compatibility.
+ * Rename let scoping transformer to block scoping.

bin/6to5/file.js

@@ -63,7 +63,7 @@ module.exports = function (commander, filenames) {
 
       fs.writeFileSync(commander.outFile, result.code);
     } else {
-      console.log(result.code);
+      process.stdout.write(result.code + "\n");
     }
   };
 

bin/6to5/index.js

@@ -34,13 +34,10 @@ commander.on("--help", function(){
     console.log("  " + title + ":");
     console.log();
 
-    var hasOptional = true;
-
     _.each(_.keys(obj).sort(), function (key) {
       if (key[0] === "_") return;
 
       if (obj[key].optional) {
-        hasOptional = true;
         key = "[" + key + "]";
       }
 

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

@@ -152,7 +152,7 @@ ReplaceSupers.prototype.getThisReference = function () {
     return this.topLevelThisReference;
   } else {
     var ref = this.topLevelThisReference = this.file.generateUidIdentifier("this");
-    this.methodNode.body.body.unshift(t.variableDeclaration("var", [
+    this.methodNode.value.body.body.unshift(t.variableDeclaration("var", [
       t.variableDeclarator(this.topLevelThisReference, t.thisExpression())
     ]));
     return ref;

lib/6to5/transformation/transform.js

@@ -79,6 +79,7 @@ _.each({
 
   constants:                 require("./transformers/es6-constants"),
   letScoping:                require("./transformers/es6-let-scoping"),
+  blockScopingTDZ:           require("./transformers/optional-block-scoping-tdz"),
 
   _blockHoist:               require("./transformers/_block-hoist"),
 

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

@@ -57,6 +57,7 @@ exports.Loop = function (node, parent, scope, context, file) {
   }
 };
 
+exports.Program =
 exports.BlockStatement = function (block, parent, scope, context, file) {
   if (!t.isLoop(parent)) {
     var letScoping = new LetScoping(false, block, parent, scope, file);
@@ -82,7 +83,8 @@ function LetScoping(loopParent, block, parent, scope, file) {
   this.file       = file;
 
   this.outsideLetReferences = {};
-  this.letReferences        = {};
+  this.hasLetReferences     = false;
+  this.letReferences        = block._letReferences = {};
   this.body                 = [];
 }
 
@@ -95,10 +97,14 @@ LetScoping.prototype.run = function () {
   if (block._letDone) return;
   block._letDone = true;
 
-  // this is a block within a `Function` so we can safely leave it be
-  if (t.isFunction(this.parent)) return;
-
   var needsClosure = this.getLetReferences();
+
+  // this is a block within a `Function/Program` so we can safely leave it be
+  if (t.isFunction(this.parent) || t.isProgram(this.block)) return;
+
+  // we can skip everything
+  if (!this.hasLetReferences) return;
+
   if (needsClosure) {
     this.needsClosure();
   } else {
@@ -130,7 +136,7 @@ LetScoping.prototype.remap = function () {
       var uid = file.generateUidIdentifier(ref.name, scope).name;
       ref.name = uid;
 
-      remaps[key] = {
+      remaps[key] = remaps[uid] = {
         node: ref,
         uid: uid
       };
@@ -239,8 +245,12 @@ LetScoping.prototype.getLetReferences = function () {
     declar = declarators[i];
     var keys = t.getIds(declar, true);
     _.extend(this.letReferences, keys);
+    this.hasLetReferences = true;
   }
 
+  // no let references so we can just quit
+  if (!this.hasLetReferences) return;
+
   // set let references to plain var references
   standardiseLets(declarators);
 

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

@@ -0,0 +1,47 @@
+var traverse = require("../../traverse");
+var t        = require("../../types");
+
+exports.optional = true;
+
+exports.Loop =
+exports.Program =
+exports.BlockStatement = function (node, parent, scope, context, file) {
+  var letRefs = node._letReferences;
+  if (!letRefs) return;
+
+  var state = {
+    letRefs: letRefs,
+    file: file
+  };
+
+  traverse(node, {
+    enter: function (node, parent, scope, context, state) {
+      if (!t.isIdentifier(node)) return;
+      if (!t.isReferenced(node, parent)) return;
+
+      var declared = state.letRefs[node.name];
+      if (!declared) return;
+
+      // declared node is different in this scope
+      if (scope.get(node.name, true) !== declared) return;
+
+      var declaredLoc  = declared.loc;
+      var referenceLoc = node.loc;
+
+      if (!declaredLoc || !referenceLoc) return;
+
+      // does this reference appear on a line before the declaration?
+      var before = referenceLoc.start.line < declaredLoc.start.line;
+
+      if (referenceLoc.start.line === declaredLoc.start.line) {
+        // this reference appears on the same line
+        // check it appears before the declaration
+        before = referenceLoc.start.col < declaredLoc.start.col;
+      }
+
+      if (before) {
+        throw state.file.errorWithNode(node, "Temporal dead zone - accessing a variable before it's initialized");
+      }
+    }
+  }, scope, state);
+};

lib/6to5/transformation/transformers/spec-block-scoped-functions.js

@@ -7,6 +7,9 @@ exports.FunctionDeclaration = function (node, parent) {
     return;
   }
 
+  // this is to avoid triggering the TDZ detection
+  node.id.loc = null;
+
   var declar = t.variableDeclaration("let", [
     t.variableDeclarator(node.id, t.toExpression(node))
   ]);

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.13.0",
+  "version": "2.13.2",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://6to5.org/",
   "repository": "6to5/6to5",

test/fixtures/transformation/es6-let-scoping/temporal-dead-zone/actual.js

@@ -0,0 +1,2 @@
+qux;
+let qux = 456;

test/fixtures/transformation/es6-let-scoping/temporal-dead-zone/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "Temporal dead zone - accessing a variable before it's initialized",
+  "optional": ["blockScopingTDZ"]
+}