v2.13.5

CHANGELOG.md

@@ -11,6 +11,23 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 2.13.5
+
+ * **Bug Fix**
+  * Allow rest parameters to be destructuring patterns.
+ * **Internal**
+  * Upgrade `kexec` to `1.1.0`.
+
+## 2.13.4
+
+ * **Bug Fix**
+  * Fix ordering of destructuring and default params.
+  * Fix loop body scope.
+  * Fix `for...of` transformation not retaining it's scope.
+  * Add destructuring assignment support to scope tracking.
+ * **Polish**
+  * More reliable newlines for pretty printing variable declarations.
+
 ## 2.13.3
 
  * **Internal**

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

@@ -169,20 +169,19 @@ exports.DebuggerStatement = function () {
 exports.VariableDeclaration = function (node, print, parent) {
   this.push(node.kind + " ");
 
-  var inits = 0;
-  var noInits = 0;
+  var hasInits = false;
+  // don't add whitespace to loop heads
   if (!t.isFor(parent)) {
     for (var i = 0; i < node.declarations.length; i++) {
       if (node.declarations[i].init) {
-        inits++;
-      } else {
-        noInits++;
+        // has an init so let's split it up over multiple lines
+        hasInits = true;
       }
     }
   }
 
   var sep = ",";
-  if (inits > noInits) { // more inits than no inits so let's add a newline
+  if (hasInits) {
     sep += "\n" + util.repeat(node.kind.length + 1);
   } else {
     sep += " ";

lib/6to5/transformation/templates/array-comprehension-for-each.js

@@ -1,3 +0,0 @@
-ARRAY.forEach(function (KEY) {
-
-});

lib/6to5/transformation/transform.js

@@ -71,8 +71,9 @@ _.each({
   templateLiterals:          require("./transformers/es6-template-literals"),
   propertyMethodAssignment:  require("./transformers/es6-property-method-assignment"),
   computedPropertyNames:     require("./transformers/es6-computed-property-names"),
-  destructuring:             require("./transformers/es6-destructuring"),
   defaultParameters:         require("./transformers/es6-default-parameters"),
+  restParameters:            require("./transformers/es6-rest-parameters"),
+  destructuring:             require("./transformers/es6-destructuring"),
   forOf:                     require("./transformers/es6-for-of"),
   unicodeRegex:              require("./transformers/es6-unicode-regex"),
   abstractReferences:        require("./transformers/es7-abstract-references"),
@@ -84,7 +85,6 @@ _.each({
   _blockHoist:               require("./transformers/_block-hoist"),
 
   generators:                require("./transformers/es6-generators"),
-  restParameters:            require("./transformers/es6-rest-parameters"),
 
   protoToAssign:             require("./transformers/optional-proto-to-assign"),
 
@@ -98,6 +98,7 @@ _.each({
   typeofSymbol:              require("./transformers/optional-typeof-symbol"),
   coreAliasing:              require("./transformers/optional-core-aliasing"),
   undefinedToVoid:           require("./transformers/optional-undefined-to-void"),
+  undeclaredVariableCheck:   require("./transformers/optional-undeclared-variable-check"),
 
   // spec
   specPropertyLiterals:         require("./transformers/spec-property-literals"),

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

@@ -15,9 +15,9 @@ exports.Function = function (node, parent, scope, context, file) {
   var iife = false;
   var def;
 
-  var checkTDZ = function (ids) {
+  var checkTDZ = function (param, def, ids) {
     var check = function (node, parent) {
-      if (!t.isIdentifier(node) || !t.isReferenced(node, parent)) return;
+      if (!t.isReferencedIdentifier(node, parent)) return;
 
       if (ids.indexOf(node.name) >= 0) {
         throw file.errorWithNode(node, "Temporal dead zone - accessing a variable before it's initialized");
@@ -29,7 +29,10 @@ exports.Function = function (node, parent, scope, context, file) {
     };
 
     check(def, node);
-    traverse(def, { enter: check });
+
+    if (!t.isPattern(param)) {
+      traverse(def, { enter: check });
+    }
   };
 
   for (var i = 0; i < node.defaults.length; i++) {
@@ -42,7 +45,7 @@ exports.Function = function (node, parent, scope, context, file) {
     // are to the right - ie. uninitialized parameters
     var rightIds = ids.slice(i);
     for (var i2 = 0; i2 < rightIds.length; i2++) {
-      checkTDZ(rightIds[i2]);
+      checkTDZ(param, def, rightIds[i2]);
     }
 
     // we're accessing a variable that's already defined within this function
@@ -66,12 +69,14 @@ exports.Function = function (node, parent, scope, context, file) {
       continue;
     }
 
-    body.push(util.template("default-parameter", {
+    var defNode = util.template("default-parameter", {
       VARIABLE_NAME: node.params[i],
       DEFAULT_VALUE: def,
       ARGUMENT_KEY:  t.literal(+i),
       ARGUMENTS:     argsIdentifier
-    }, true));
+    }, true);
+    defNode._blockHoist = node.defaults.length - i;
+    body.push(defNode);
   }
 
   // we need to cut off all trailing default parameters

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

@@ -8,13 +8,27 @@ var buildVariableAssign = function (opts, id, init) {
   var op = opts.operator;
   if (t.isMemberExpression(id)) op = "=";
 
+  var node;
+
   if (op) {
-    return t.expressionStatement(t.assignmentExpression(op, id, init));
+    node = t.expressionStatement(t.assignmentExpression(op, id, init));
   } else {
-    return t.variableDeclaration(opts.kind, [
+    node = t.variableDeclaration(opts.kind, [
       t.variableDeclarator(id, init)
     ]);
   }
+
+  node._blockHoist = opts.blockHoist;
+
+  return node;
+};
+
+var buildVariableDeclar = function (opts, id, init) {
+  var declar = t.variableDeclaration("var", [
+    t.variableDeclarator(id, init)
+  ]);
+  declar._blockHoist = opts.blockHoist;
+  return declar;
 };
 
 var push = function (opts, nodes, elem, parentId) {
@@ -100,9 +114,7 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
   var toArray = opts.file.toArray(parentId, !hasSpreadElement && pattern.elements.length);
 
   var _parentId = opts.scope.generateUidBasedOnNode(parentId, opts.file);
-  nodes.push(t.variableDeclaration("var", [
-    t.variableDeclarator(_parentId, toArray)
-  ]));
+  nodes.push(buildVariableDeclar(opts, _parentId, toArray));
   parentId = _parentId;
 
   for (i = 0; i < pattern.elements.length; i++) {
@@ -138,11 +150,7 @@ var pushPattern = function (opts) {
 
   if (!t.isArrayExpression(parentId) && !t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
     var key = scope.generateUidBasedOnNode(parentId, file);
-
-    nodes.push(t.variableDeclaration("var", [
-      t.variableDeclarator(key, parentId)
-    ]));
-
+    nodes.push(buildVariableDeclar(opts, key, parentId));
     parentId = key;
   }
 
@@ -181,19 +189,20 @@ exports.Function = function (node, parent, scope, context, file) {
 
   var hasDestructuring = false;
 
-  node.params = node.params.map(function (pattern) {
+  node.params = node.params.map(function (pattern, i) {
     if (!t.isPattern(pattern)) return pattern;
 
     hasDestructuring = true;
     var parentId = file.generateUidIdentifier("ref", scope);
 
     pushPattern({
-      kind:    "var",
-      nodes:   nodes,
-      pattern: pattern,
-      id:      parentId,
-      file:    file,
-      scope:   scope
+      blockHoist: node.params.length - i,
+      pattern:    pattern,
+      nodes:      nodes,
+      scope:      scope,
+      file:       file,
+      kind:       "var",
+      id:         parentId
     });
 
     return parentId;
@@ -294,12 +303,12 @@ exports.VariableDeclaration = function (node, parent, scope, context, file) {
     var patternId = declar.init;
     var pattern   = declar.id;
     var opts = {
-      kind:    node.kind,
-      nodes:   nodes,
       pattern: pattern,
-      id:      patternId,
+      nodes:   nodes,
+      scope:   scope,
+      kind:    node.kind,
       file:    file,
-      scope:   scope
+      id:      patternId,
     };
 
     if (t.isPattern(pattern) && patternId) {

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

@@ -30,6 +30,9 @@ exports.ForOfStatement = function (node, parent, scope, context, file) {
   // push the rest of the original loop body onto our new body
   block.body = block.body.concat(node.body.body);
 
+  // todo: find out why this is necessary? #538
+  loop._scopeInfo = node._scopeInfo;
+
   return loop;
 };
 

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

@@ -117,9 +117,10 @@ LetScoping.prototype.run = function () {
  */
 
 LetScoping.prototype.remap = function () {
-  var letRefs = this.letReferences;
-  var scope   = this.scope;
-  var file    = this.file;
+  var hasRemaps = false;
+  var letRefs   = this.letReferences;
+  var scope     = this.scope;
+  var file      = this.file;
 
   // alright, so since we aren't wrapping this block in a closure
   // we have to check if any of our let variables collide with
@@ -136,6 +137,7 @@ LetScoping.prototype.remap = function () {
       var uid = file.generateUidIdentifier(ref.name, scope).name;
       ref.name = uid;
 
+      hasRemaps = true;
       remaps[key] = remaps[uid] = {
         node: ref,
         uid: uid
@@ -143,11 +145,12 @@ LetScoping.prototype.remap = function () {
     }
   }
 
+  if (!hasRemaps) return;
+
   //
 
   var replace = function (node, parent, scope, context, remaps) {
-    if (!t.isIdentifier(node)) return;
-    if (!t.isReferenced(node, parent)) return;
+    if (!t.isReferencedIdentifier(node, parent)) return;
 
     var remap = remaps[node.name];
     if (!remap) return;
@@ -266,11 +269,8 @@ LetScoping.prototype.getLetReferences = function () {
       if (t.isFunction(node)) {
         traverse(node, {
           enter: function (node, parent) {
-            // not an identifier so we have no use
-            if (!t.isIdentifier(node)) return;
-
             // not a direct reference
-            if (!t.isReferenced(node, parent)) return;
+            if (!t.isReferencedIdentifier(node, parent)) return;
 
             // this scope has a variable with the same name so it couldn't belong
             // to our let scope

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

@@ -41,6 +41,22 @@ exports.Function = function (node, parent, scope, context, file) {
     );
   }
 
+  // support patterns
+  if (t.isPattern(rest)) {
+    var pattern = rest;
+    rest = file.generateUidIdentifier("ref", scope);
+
+    // let the destructuring transformer handle this
+    var restDeclar = t.variableDeclaration("var", [
+      t.variableDeclarator(pattern, rest)
+    ]);
+
+    // retain evaluation position
+    restDeclar._blockHoist = node.params.length + 1;
+
+    node.body.body.unshift(restDeclar);
+  }
+
   node.body.body.unshift(
     util.template("rest", {
       ARGUMENTS: argsId,

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

@@ -16,8 +16,7 @@ exports.BlockStatement = function (node, parent, scope, context, file) {
 
   traverse(node, {
     enter: function (node, parent, scope, context, state) {
-      if (!t.isIdentifier(node)) return;
-      if (!t.isReferenced(node, parent)) return;
+      if (!t.isReferencedIdentifier(node, parent)) return;
 
       var declared = state.letRefs[node.name];
       if (!declared) return;

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -42,7 +42,7 @@ exports.ast = {
             context.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && _.contains(ALIASABLE_CONSTRUCTORS, node.name)) {
+        } else if (t.isReferencedIdentifier(node, parent) && !t.isMemberExpression(parent) && _.contains(ALIASABLE_CONSTRUCTORS, node.name)) {
           // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {

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

@@ -0,0 +1,7 @@
+exports.optional = true;
+
+exports.Identifier = function (node, parent, scope, context, file) {
+  if (!scope.has(node.name, true)) {
+    throw file.errorWithNode(node, "Reference to undeclared variable");
+  }
+};

lib/6to5/traverse/scope.js

@@ -120,6 +120,7 @@ Scope.prototype.generateTempBasedOnNode = function (node, file) {
 };
 
 Scope.prototype.getInfo = function () {
+  var parent = this.parent;
   var block = this.block;
   if (block._scopeInfo) return block._scopeInfo;
 
@@ -132,6 +133,10 @@ Scope.prototype.getInfo = function () {
     if (!reference) Scope.add(node, declarations);
   };
 
+  if (parent && t.isBlockStatement(block) && t.isFor(parent.block)) {
+    return info;
+  }
+
   // ForStatement - left, init
 
   if (t.isFor(block)) {
@@ -139,6 +144,10 @@ Scope.prototype.getInfo = function () {
       var node = block[key];
       if (t.isBlockScoped(node)) add(node);
     });
+
+    if (t.isBlockStatement(block.body)) {
+      block = block.body;
+    }
   }
 
   // Program, BlockStatement - let variables

lib/6to5/types/index.js

@@ -263,6 +263,18 @@ t.isReferenced = function (node, parent) {
   return false;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} parent
+ * @returns {Boolean}
+ */
+
+t.isReferencedIdentifier = function (node, parent) {
+  return t.isIdentifier(node) && t.isReferenced(node, parent);
+};
+
 /**
  * Description
  *
@@ -475,7 +487,8 @@ t.getIds.nodes = {
   MemeberExpression: ["object"],
   SpreadElement: ["argument"],
   Property: ["value"],
-  ComprehensionBlock: ["left"]
+  ComprehensionBlock: ["left"],
+  AssignmentPattern: ["left"]
 };
 
 t.getIds.arrays = {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.13.3",
+  "version": "2.13.5",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://6to5.org/",
   "repository": "6to5/6to5",
@@ -63,6 +63,6 @@
     "uglify-js": "2.4.16"
   },
   "optionalDependencies": {
-    "kexec": "0.2.0"
+    "kexec": "1.1.0"
   }
 }

test/fixtures/generation/types/VariableDeclaration-VariableDeclarator/expected.js

@@ -5,8 +5,10 @@ let foo = "foo";
 var foo = "bar";
 const foo = "foo";
 
-let foo, bar = "bar";
-var foo, bar = "bar";
+let foo,
+    bar = "bar";
+var foo,
+    bar = "bar";
 
 let foo = "foo",
     bar = "bar";

test/fixtures/transformation/es6-default-parameters/destructuring/exec.js

@@ -0,0 +1,19 @@
+function required(msg) {
+  throw new Error(msg);
+}
+
+function sum(
+  { arr = required('arr is required') } = { arr: arr = [] },
+  length = arr.length
+) {
+  let i = 0;
+  let acc = 0;
+  for (let item of arr) {
+    if (i >= length) return acc;
+    acc += item;
+    i++;
+  }
+  return acc;
+}
+
+assert.equal(sum({arr:[1,2]}), 3);

test/fixtures/transformation/es6-let-scoping/exec-collision-array-comprehension/exec.js

@@ -0,0 +1,2 @@
+var foo = [];
+assert.deepEqual([for (foo of [1, 2, 3]) foo], [1, 2, 3]);

test/fixtures/transformation/es6-let-scoping/exec-collision-array-comprehension/options.json

@@ -0,0 +1,3 @@
+{
+  "experimental": true
+}

test/fixtures/transformation/es6-let-scoping/exec-collision-for/exec.js

@@ -0,0 +1,6 @@
+let x = 0;
+for (;;) {
+  let x = 1;
+  assert.equal(x, 1);
+  break;
+}

test/fixtures/transformation/es6-let-scoping/exec-destructuring-defaults/exec.js

@@ -0,0 +1,5 @@
+var fields = [{ name: "title" }, { name: "content" }];
+
+for (let { name, value = "Default value" } of fields) {
+  assert.equal(value, "Default value");
+}

test/fixtures/transformation/optional-undeclared-variable-check/declared/exec.js

@@ -0,0 +1,5 @@
+function foo() {
+  
+}
+
+foo();

test/fixtures/transformation/optional-undeclared-variable-check/options.json

@@ -0,0 +1,3 @@
+{
+  "optional": ["undeclaredVariableCheck"]
+}

test/fixtures/transformation/optional-undeclared-variable-check/undeclared/exec.js

@@ -0,0 +1 @@
+foo();

test/fixtures/transformation/optional-undeclared-variable-check/undeclared/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Reference to undeclared variable"
+}