v2.4.6

Extend the license to the new year

CHANGELOG.md

@@ -2,6 +2,35 @@
 
 Gaps between patch versions are faulty/broken releases.
 
+## 2.4.6
+
+ * Move `coreAliasing` and `undefinedToVoid` transformers down to catch `moduleFormatter` transforms.
+
+## 2.4.5
+
+ * Avoid printing comments if they've already been output.
+
+## 2.4.4
+
+ * Add `module` type to browser build `<script>` handler.
+ * Fix some `MemberExpression` modifying incorrectly setting `property` to a `MemberExpression`.
+
+## 2.4.3
+
+ * Upgrade `acorn-6to5`.
+ * Add support for `FunctionDeclaration`s in `bluebirdCoroutines` and `asyncToGenerators` transformers.
+
+## 2.4.2
+
+ * Upgrade `acorn-6to5`.
+ * Better uids generated for various transformers based on parent node.
+ * Alias flat references in `coreAliasing` transformer.
+
+## 2.4.1
+
+ * Better whitespace handling of parenthesized expressions due to trailing comments.
+ * Fix `yield` inside of comprehensions.
+
 ## 2.4.0
 
  * Use a closure always for classes with a super.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2014 Sebastian McKenzie
+Copyright (c) 2014-2015 Sebastian McKenzie
 
 MIT License
 

README.md

@@ -11,10 +11,6 @@
     <img alt="Travis Status" src="http://img.shields.io/travis/6to5/6to5/master.svg?style=flat&amp;label=travis">
   </a>
 
-  <a href="https://ci.appveyor.com/project/sebmck/6to5">
-    <img alt="Appveyor Status" src="http://img.shields.io/appveyor/ci/sebmck/6to5.svg?style=flat&amp;label=appveyor">
-  </a>
-
   <a href="https://codeclimate.com/github/6to5/6to5">
     <img alt="Code Climate Score" src="http://img.shields.io/codeclimate/github/6to5/6to5.svg?style=flat">
   </a>

doc/caveats.md

@@ -9,12 +9,15 @@ You may alternatively selectively include what you need:
 | Feature                     | Requirements                                                                                                           |
 | --------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
 | Abstract References         | [experimental](experimental.md), `Symbol`                                                                              |
-| Array destructuring         | `Array.isArray`, `Array.from`                                                                                          |
+| Array destructuring         | `Array.from`                                                                                                           |
 | Async functions, Generators | [experimental](experimental.md), [regenerator runtime](https://github.com/facebook/regenerator/blob/master/runtime.js) |
-| Comprehensions              | [experimental](experimental.md), `Array.isArray`, `Array.from`                                                         |
+| Comprehensions              | [experimental](experimental.md), `Array.from`                                                                          |
 | For Of                      | `Symbol`, `prototype[Symbol.iterator]`                                                                                 |
+| Modules                     | `Object.assign`*                                                                                                       |
 | Object spread/rest          | [experimental](experimental.md), `Object.assign`                                                                       |
-| Spread                      | `Array.isArray`, `Array.from`                                                                                          |
+| Spread                      | `Array.from`                                                                                                           |
+
+*Only required for exporting a non-function `default` with additional `export`s.
 
 ## ES5
 
@@ -26,13 +29,13 @@ ES5 such as lower versions of IE then using the
 
 ## Internet Explorer
 
-### Classes (9 and below)
+### Classes (10 and below)
 
 If you're inheriting from a class then static properties are inherited from it
 via [\_\_proto\_\_](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto),
 this is widely supported but you may run into problems with much older browsers.
 
-**NOTE:** `__proto__` is not supported on IE <= 9 so static properties
+**NOTE:** `__proto__` is not supported in IE <= 10 so static properties
 **will not** be inherited. A possible workaround is to use `super();`:
 
 ```javascript
@@ -56,4 +59,4 @@ unfortunate as it's required to set getters and setters. Due to this if
 you plan on supporting IE8 or below then the user of getters and setters
 isn't recommended.
 
-Reference: [MDN](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty#Internet_Explorer_8_specific_notes).
+**Reference**: [MDN](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty#Internet_Explorer_8_specific_notes).

doc/index.md

@@ -52,7 +52,7 @@ And it doesn't end here! To see all the ways you can use 6to5, check out the
  - [Let scoping](features.md#let-scoping)
  - [Modules](features.md#modules)
  - [Numeric literals](features.md#numeric-literals)
- - [Object Rest/Spread](features.md#object-rest-spread) ([experimental](experimental.md))
+ - [Object rest/spread](features.md#object-rest-spread) ([experimental](experimental.md))
  - [Property method assignment](features.md#property-method-assignment)
  - [Property name shorthand](features.md#property-name-shorthand)
  - [React/JSX](react.md)

doc/playground.md

@@ -18,11 +18,19 @@ to5.transform("code", { playground: true });
 
  * [Memoization operator](#memoization-operator)
  * [Method binding](#method-binding)
+ * [Method binding function shorthand](#method-binding-function-shorthand)
  * [Object getter memoization](#object-getter-memoization)
  * [This shorthand](#this-shorthand)
 
 ### Memoization assignment operator
 
+The memoization assignment operator allows you to lazily set an object property.
+It checks whether there's a property defined on the object and if there isn't then
+the right hand value is set.
+
+This means that `obj.x` in the following `var x = { x: undefined }; obj.x ?= 2;`
+will still be `undefined` because it's already been defined on the object.
+
 ```javascript
 var obj = {};
 obj.x ?= 2;
@@ -42,7 +50,7 @@ var obj = {};
 obj.x ?= 2;
 ```
 
-equivalent to:
+equivalent to
 
 ```javascript
 var obj = {};
@@ -54,17 +62,25 @@ if (!Object.prototype.hasOwnProperty.call(obj, "x")) obj.x = 2;
 ```javascript
 var fn = obj#method;
 var fn = obj#method("foob");
-
-["foo", "bar"].map(#toUpperCase); // ["FOO", "BAR"]
-[1.1234, 23.53245, 3].map(#toFixed(2)); // ["1.12", "23.53", "3.00"]
 ```
 
-equivalent to:
+equivalent to
 
 ```javascript
 var fn = obj.method.bind(obj);
 var fn = obj.method.bind(obj, "foob");
+```
 
+### Method binding function shorthand
+
+```javascript
+["foo", "bar"].map(#toUpperCase); // ["FOO", "BAR"]
+[1.1234, 23.53245, 3].map(#toFixed(2)); // ["1.12", "23.53", "3.00"]
+```
+
+equivalent to
+
+```javascript
 ["foo", "bar"].map(function (val) { return val.toUpperCase(); });
 [1.1234, 23.53245, 3].map(function (val) { return val.toFixed(2); });
 ```
@@ -90,23 +106,27 @@ equivalent to
 ```javascript
 var foo = {
   get bar() {
-    if (this._barRan) return this._bar;
-    this._barRan = true;
-    return this._bar = complex();
+    return Object.defineProperty(this, "bar", {
+      value: complex(),
+      enumerable: true,
+      configurable: true,
+      writable: true
+    }).bar;
   }
 };
 
 class Foo {
   get bar() {
-    if (this._barRan) return this._bar;
-    this._barRan = true;
-    return this._bar = complex();
+    return Object.defineProperty(this, "bar", {
+      value: complex(),
+      enumerable: true,
+      configurable: true,
+      writable: true
+    }).bar;
   }
 }
 ```
 
-**NOTE:** Memoised functions will return the result of the **first** execution, regardless of arguments.
-
 ### This shorthand
 
 ```javascript

lib/6to5/browser.js

@@ -34,7 +34,7 @@ transform.load = function (url, callback, opts, hold) {
 
 var runScripts = function () {
   var scripts = [];
-  var types   = ["text/ecmascript-6", "text/6to5"];
+  var types   = ["text/ecmascript-6", "text/6to5", "module"];
   var index   = 0;
 
   var exec = function () {
@@ -60,8 +60,9 @@ var runScripts = function () {
     }
   };
 
-  var _scripts = global.document.getElementsByTagName("script");
-  for (var i in _scripts) {
+  var _scripts = global.document .getElementsByTagName("script");
+
+  for (var i = 0; i < _scripts.length; ++i) {
     var _script = _scripts[i];
     if (types.indexOf(_script.type) >= 0) scripts.push(_script);
   }

lib/6to5/file.js

@@ -10,10 +10,11 @@ var t         = require("./types");
 var _         = require("lodash");
 
 function File(opts) {
-  this.opts         = File.normaliseOptions(opts);
-  this.transformers = this.getTransformers();
-  this.uids         = {};
-  this.ast          = {};
+  this.dynamicImports = [];
+  this.opts           = File.normaliseOptions(opts);
+  this.transformers   = this.getTransformers();
+  this.uids           = {};
+  this.ast            = {};
 }
 
 File.declarations = [
@@ -156,7 +157,8 @@ File.prototype.parseShebang = function (code) {
 File.prototype.addImport = function (id, source) {
   var specifiers = [t.importSpecifier(t.identifier("default"), id)];
   var declar = t.importDeclaration(specifiers, t.literal(source));
-  this.ast.program.body.unshift(declar);
+  declar._blockHoist = 3;
+  this.dynamicImports.push(declar);
 };
 
 File.prototype.addDeclaration = function (name) {

lib/6to5/generation/generator.js

@@ -148,10 +148,11 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
   };
 
   if (this[node.type]) {
-    // only compute if this node needs parens if our parent has been changed
-    // since acorn would've wrapped us in a ParanthesizedExpression
-    var needsParens = n.needsParens(node, parent);
+    var needsCommentParens = t.isExpression(node) && node.leadingComments && node.leadingComments.length;
+    var needsParens        = needsCommentParens || n.needsParens(node, parent);
+
     if (needsParens) this.push("(");
+    if (needsCommentParens) this.indent();
 
     this.printLeadingComments(node, parent);
 
@@ -162,6 +163,10 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
 
     this[node.type](node, this.buildPrint(node), parent);
 
+    if (needsCommentParens) {
+      this.newline();
+      this.dedent();
+    }
     if (needsParens) this.push(")");
 
     this.map.mark(node, "end");
@@ -269,14 +274,21 @@ CodeGenerator.prototype._printComments = function (comments) {
   var self = this;
 
   _.each(comments, function (comment) {
+    var skip = false;
+
     // find the original comment in the ast and set it as displayed
     _.each(self.ast.comments, function (origComment) {
       if (origComment.start === comment.start) {
+        // comment has already been output
+        if (origComment._displayed) skip = true;
+
         origComment._displayed = true;
         return false;
       }
     });
 
+    if (skip) return;
+
     // whitespace before
     self.newline(self.whitespace.getNewlinesBefore(comment));
 

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

@@ -98,6 +98,10 @@ exports.MemberExpression = function (node, print) {
   var obj = node.object;
   print(obj);
 
+  if (!node.computed && t.isMemberExpression(node.property)) {
+    throw new TypeError("Got a MemberExpression for MemberExpression property");
+  }
+
   if (node.computed) {
     this.push("[");
     print(node.property);

lib/6to5/generation/node/index.js

@@ -60,10 +60,6 @@ Node.prototype.needsParens = function () {
 
   if (!parent) return false;
 
-  if (t.isExpression(node) && node.leadingComments && node.leadingComments.length) {
-    return true;
-  }
-
   if (t.isNewExpression(parent) && parent.callee === node) {
     return t.isCallExpression(node) || _.some(node, function (val) {
       return t.isCallExpression(val);

lib/6to5/transformation/transform.js

@@ -83,14 +83,14 @@ _.each({
 
   _declarations:             require("./transformers/_declarations"),
 
-  coreAliasing:              require("./transformers/optional-core-aliasing"),
-  undefinedToVoid:           require("./transformers/optional-undefined-to-void"),
-
   // wrap up
   _aliasFunctions:           require("./transformers/_alias-functions"),
   _moduleFormatter:          require("./transformers/_module-formatter"),
   useStrict:                 require("./transformers/use-strict"),
 
+  coreAliasing:              require("./transformers/optional-core-aliasing"),
+  undefinedToVoid:           require("./transformers/optional-undefined-to-void"),
+
   // spec
   specPropertyLiterals:         require("./transformers/spec-property-literals"),
   specMemberExpressionLiterals: require("./transformers/spec-member-expression-literals")

lib/6to5/transformation/transformers/es5-property-method-assignment.js

@@ -1,4 +1,5 @@
 var util = require("../../util");
+var t    = require("../../types");
 
 exports.Property = function (node) {
   if (node.method) node.method = false;
@@ -21,7 +22,7 @@ exports.ObjectExpression = function (node, parent, file) {
   if (!hasAny) return;
 
   if (node.properties.length) {
-    var objId = util.getUid(parent, file);
+    var objId = t.getUid(parent, file);
 
     return util.template("object-define-properties-closure", {
       KEY: objId,

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

@@ -87,11 +87,9 @@ Class.prototype.run = function () {
 
   if (superName) {
     this.closure = true;
-    // so we're only evaluating it once
-    var superRefName = "super";
-    if (className) superRefName = className.name + "Super";
 
-    var superRef = file.generateUidIdentifier(superRefName, this.scope);
+    // so we're only evaluating it once
+    var superRef = t.getUid(superName, this.file);
     body.unshift(t.variableDeclaration("var", [
       t.variableDeclarator(superRef, superName)
     ]));
@@ -278,7 +276,7 @@ Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
         if (callee.object.name !== "super") return;
 
         // super.test(); -> ClassName.prototype.MethodName.call(this);
-        callee.property = t.memberExpression(callee.property, t.identifier("call"));
+        t.appendToMemberExpression(callee, t.identifier("call"));
         node.arguments.unshift(t.thisExpression());
       }
     }

lib/6to5/transformation/transformers/es6-computed-property-names.js

@@ -1,5 +1,4 @@
-var util = require("../../util");
-var t    = require("../../types");
+var t = require("../../types");
 
 exports.ObjectExpression = function (node, parent, file) {
   var hasComputed = false;
@@ -14,7 +13,7 @@ exports.ObjectExpression = function (node, parent, file) {
 
   if (!hasComputed) return;
 
-  var objId = util.getUid(parent, file);
+  var objId = t.getUid(parent, file);
 
   var body = [];
   var container = t.functionExpression(null, [], t.blockStatement(body));

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

@@ -75,7 +75,7 @@ var pushArrayPattern = function (opts, nodes, pattern, parentId) {
 
   var toArray = opts.file.toArray(parentId, !hasSpreadElement && pattern.elements.length);
 
-  var _parentId = opts.file.generateUidIdentifier("ref", opts.scope);
+  var _parentId = t.getUid(parentId, opts.file, opts.scope);
   nodes.push(t.variableDeclaration("var", [
     t.variableDeclarator(_parentId, toArray)
   ]));
@@ -113,7 +113,7 @@ var pushPattern = function (opts) {
   var scope = opts.scope;
 
   if (!t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
-    var key = file.generateUidIdentifier("ref", scope);
+    var key = t.getUid(parentId, file, scope);
 
     nodes.push(t.variableDeclaration("var", [
       t.variableDeclarator(key, parentId)

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

@@ -1,5 +1,11 @@
 var t = require("../../types");
 
+exports.ast = {
+  before: function (ast, file) {
+    ast.program.body = file.dynamicImports.concat(ast.program.body);
+  }
+};
+
 exports.ImportDeclaration = function (node, parent, file) {
   var nodes = [];
 
@@ -11,6 +17,12 @@ exports.ImportDeclaration = function (node, parent, file) {
     file.moduleFormatter.importDeclaration(node, nodes, parent);
   }
 
+  if (nodes.length === 1) {
+    // inherit `_blockHoist`
+    // this for `_blockHoist` in File.prototype.addImport
+    nodes[0]._blockHoist = node._blockHoist;
+  }
+
   return nodes;
 };
 

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

@@ -87,13 +87,7 @@ exports.CallExpression = function (node, parent, file, scope) {
       callee.object = t.assignmentExpression("=", temp, callee.object);
     }
 
-    if (callee.computed) {
-      callee.object = t.memberExpression(callee.object, callee.property, true);
-      callee.property = t.identifier("apply");
-      callee.computed = false;
-    } else {
-      callee.property = t.memberExpression(callee.property, t.identifier("apply"));
-    }
+    t.appendToMemberExpression(callee, t.identifier("apply"));
   } else {
     node.callee = t.memberExpression(node.callee, t.identifier("apply"));
   }

lib/6to5/transformation/transformers/es7-array-comprehension.js

@@ -4,8 +4,8 @@ var t        = require("../../types");
 
 exports.experimental = true;
 
-var build = function (node, file) {
-  var uid = file.generateUidIdentifier("arr");
+var build = function (node, parent, file, scope) {
+  var uid = t.getUid(parent, file, scope);
 
   var container = util.template("array-comprehension-container", {
     KEY: uid
@@ -16,7 +16,7 @@ var build = function (node, file) {
   var body  = block.body;
 
   if (traverse.hasType(node, "YieldExpression", t.FUNCTION_TYPES)) {
-    container.generator = true;
+    container.callee.generator = true;
     container = t.yieldExpression(container, true);
   }
 
@@ -55,8 +55,8 @@ exports._build = function (node, buildBody) {
   );
 };
 
-exports.ComprehensionExpression = function (node, parent, file) {
+exports.ComprehensionExpression = function (node, parent, file, scope) {
   if (node.generator) return;
 
-  return build(node, file);
+  return build(node, parent, file, scope);
 };

lib/6to5/transformation/transformers/optional-async-to-generator.js

@@ -1,5 +1,4 @@
 var bluebirdCoroutines = require("./optional-bluebird-coroutines");
-var t                  = require("../../types");
 
 exports.optional = true;
 
@@ -8,7 +7,5 @@ exports.manipulateOptions = bluebirdCoroutines.manipulateOptions;
 exports.Function = function (node, parent, file) {
   if (!node.async || node.generator) return;
 
-  bluebirdCoroutines._Function(node);
-
-  return t.callExpression(file.addDeclaration("async-to-generator"), [node]);
+  return bluebirdCoroutines._Function(node, file.addDeclaration("async-to-generator"));
 };

lib/6to5/transformation/transformers/optional-bluebird-coroutines.js

@@ -8,7 +8,7 @@ exports.manipulateOptions = function (opts) {
 
 exports.optional = true;
 
-exports._Function = function (node) {
+exports._Function = function (node, callId) {
   node.async = false;
   node.generator = true;
 
@@ -21,14 +21,25 @@ exports._Function = function (node) {
       }
     }
   });
+
+  var call = t.callExpression(callId, [node]);
+
+  if (t.isFunctionDeclaration(node)) {
+    var declar = t.variableDeclaration("var", [
+      t.variableDeclarator(node.id, call)
+    ]);
+    declar._blockHoist = true;
+    return declar;
+  } else {
+    return call;
+  }
 };
 
 exports.Function = function (node, parent, file) {
   if (!node.async || node.generator) return;
 
-  exports._Function(node);
-
   var id = t.identifier("Bluebird");
   file.addImport(id, "bluebird");
-  return t.callExpression(t.memberExpression(id, t.identifier("coroutine")), [node]);
+
+  return exports._Function(node, t.memberExpression(id, t.identifier("coroutine")));
 };

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

@@ -4,6 +4,10 @@ var core     = require("core-js/library");
 var t        = require("../../types");
 var _        = require("lodash");
 
+var coreHas = function (node) {
+  return node.name !== "_" && _.has(core, node.name);
+};
+
 exports.optional = true;
 
 exports.ast = {
@@ -24,11 +28,13 @@ exports.ast = {
 
           if (!t.isReferenced(obj, node)) return;
 
-          var coreHasObject = obj.name !== "_" && _.has(core, obj.name);
-          if (coreHasObject && _.has(core[obj.name], prop.name)) {
+          if (!node.computed && coreHas(obj) && _.has(core[obj.name], prop.name)) {
             this.stop();
-            return t.memberExpression(file._coreId, node);
+            return t.prependToMemberExpression(node, file._coreId);
           }
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && coreHas(node)) {
+          // new Promise -> new _core.Promise
+          return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)
 

lib/6to5/transformation/transformers/playground-memoization-operator.js

@@ -10,7 +10,7 @@ var getPropRef = function (nodes, prop, file, scope) {
   if (t.isIdentifier(prop)) {
     return t.literal(prop.name);
   } else {
-    var temp = file.generateUidIdentifier("propKey", scope);
+    var temp = t.getUid(prop, file, scope);
     nodes.push(t.variableDeclaration("var", [
       t.variableDeclarator(temp, prop)
     ]));
@@ -20,7 +20,7 @@ var getPropRef = function (nodes, prop, file, scope) {
 
 var getObjRef = function (nodes, obj, file, scope) {
   if (t.isDynamic(obj)) {
-    var temp = file.generateUidIdentifier("obj", scope);
+    var temp = t.getUid(obj, file, scope);
     nodes.push(t.variableDeclaration("var", [
       t.variableDeclarator(temp, obj)
     ]));

lib/6to5/types/index.js

@@ -64,7 +64,14 @@ _.each(t.FLIPPED_ALIAS_KEYS, function (types, type) {
   addAssert(type, is);
 });
 
-//
+/*
+ * Shallowly checks to see if the passed `node` will evaluate to a
+ * falsy. This is if `node` is a `Literal` and `value` is falsy or
+ * `node` is an `Identifier` with a name of `undefiend`.
+ *
+ * @param {Object} node
+ * @returns {Boolean}
+ */
 
 t.isFalsyExpression = function (node) {
   if (t.isLiteral(node)) {
@@ -75,7 +82,14 @@ t.isFalsyExpression = function (node) {
   return false;
 };
 
-//
+/**
+ * Turn an array of statement `nodes` into a `SequenceExpression`.
+ *
+ * Variable declarations are turned into simple assignments and their
+ * declarations hoisted to the top of the current scope.
+ *
+ * Expression statements are just resolved to their standard expression.
+ */
 
 t.toSequenceExpression = function (nodes, scope) {
   var exprs = [];
@@ -116,7 +130,41 @@ t.shallowEqual = function (actual, expected) {
   return same;
 };
 
-//
+/**
+ * Description
+ *
+ * @param {Object} member
+ * @param {Object} append
+ * @param {Boolean} [computed]
+ * @returns {Object} member
+ */
+
+t.appendToMemberExpression = function (member, append, computed) {
+  member.object   = t.memberExpression(member.object, member.property, member.computed);
+  member.property = append;
+  member.computed = !!computed;
+  return member;
+};
+
+/**
+ * Description
+ *
+ * @param {Object} member
+ * @param {Object} append
+ * @returns {Object} member
+ */
+
+t.prependToMemberExpression = function (member, append) {
+  member.object = t.memberExpression(append, member.object);
+  return member;
+};
+
+/*
+ * Description
+ *
+ * @param {Object} node
+ * @returns {Boolean}
+ */
 
 t.isDynamic = function (node) {
   if (t.isExpressionStatement(node)) {
@@ -130,7 +178,14 @@ t.isDynamic = function (node) {
   }
 };
 
-// todo: https://github.com/eventualbuddha/ast-util/blob/9bf91c5ce8/lib/index.js#L454-L507
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} parent
+ * @returns {Boolean}
+ */
+
 t.isReferenced = function (node, parent) {
   // we're a property key and we aren't computed so we aren't referenced
   if (t.isProperty(parent) && parent.key === node && !parent.computed) return false;
@@ -152,11 +207,29 @@ t.isReferenced = function (node, parent) {
   return false;
 };
 
+/**
+ * Description
+ *
+ * @param {String} name
+ * @returns {Boolean}
+ */
+
+t.isValidIdentifier = function (name) {
+  return _.isString(name) && esutils.keyword.isIdentifierName(name) && !esutils.keyword.isKeywordES6(name, true);
+};
+
+/*
+ * Description
+ *
+ * @param {String} name
+ * @returns {String}
+ */
+
 t.toIdentifier = function (name) {
   if (t.isIdentifier(name)) return name.name;
 
   // replace all non-valid identifiers with dashes
-  name = name.replace(/[^a-zA-Z0-9]/g, "-");
+  name = name.replace(/[^a-zA-Z0-9$_]/g, "-");
 
   // remove all dashes and numbers from start of name
   name = name.replace(/^[-0-9]+/, "");
@@ -166,18 +239,32 @@ t.toIdentifier = function (name) {
     return c ? c.toUpperCase() : "";
   });
 
+  // remove underscores from start of name
+  name = name.replace(/^\_/, "");
+
   return name || '_';
 };
 
-t.isValidIdentifier = function (name) {
-  return _.isString(name) && esutils.keyword.isIdentifierName(name) && !esutils.keyword.isKeywordES6(name, true);
-};
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {String} key
+ */
 
 t.ensureBlock = function (node, key) {
   key = key || "body";
   node[key] = t.toBlock(node[key], node);
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Boolean} [ignore]
+ * @returns {Object|Boolean}
+ */
+
 t.toStatement = function (node, ignore) {
   if (t.isStatement(node)) {
     return node;
@@ -211,6 +298,14 @@ t.toStatement = function (node, ignore) {
   return node;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} parent
+ * @returns {Object}
+ */
+
 t.toBlock = function (node, parent) {
   if (t.isBlockStatement(node)) {
     return node;
@@ -231,6 +326,67 @@ t.toBlock = function (node, parent) {
   return t.blockStatement(node);
 };
 
+/*
+ * Description
+ *
+ * @param {Object} parent
+ * @param {File} file
+ * @param {Scope} scope
+ * @returns {Object}
+ */
+
+t.getUid = function (parent, file, scope) {
+  var node = parent;
+
+  if (t.isAssignmentExpression(parent)) {
+    node = parent.left;
+  } else if (t.isVariableDeclarator(parent)) {
+    node = parent.id;
+  }
+
+  var id = "ref";
+
+  if (t.isProperty(node)) {
+    node = node.key;
+  }
+
+  if (t.isIdentifier(node)) {
+    id = node.name;
+  } else if (t.isLiteral(node)) {
+    id = node.value;
+  } else if (t.isMemberExpression(node)) {
+    var parts = [];
+
+    var add = function (node) {
+      if (t.isMemberExpression(node)) {
+        add(node.object);
+        add(node.property);
+      } else if (t.isIdentifier(node)) {
+        parts.push(node.name);
+      } else if (t.isLiteral(node)) {
+        parts.push(node.value);
+      }
+    };
+
+    add(node);
+
+    id = parts.join("$");
+  }
+
+  id = id.replace(/^_/, "");
+
+  return file.generateUidIdentifier(id, scope);
+};
+
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Boolean} [map]
+ * @param {Array} [ignoreTypes]
+ * @returns {Array|Object}
+ */
+
 t.getIds = function (node, map, ignoreTypes) {
   ignoreTypes = ignoreTypes || [];
 
@@ -281,10 +437,24 @@ t.getIds.arrays = {
   ObjectPattern: ["properties"]
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @returns {Boolean}
+ */
+
 t.isLet = function (node) {
   return t.isVariableDeclaration(node) && (node.kind !== "var" || node._let);
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @returns {Boolean}
+ */
+
 t.isVar = function (node) {
   return t.isVariableDeclaration(node, { kind: "var" }) && !node._let;
 };
@@ -293,6 +463,13 @@ t.isVar = function (node) {
 
 t.COMMENT_KEYS = ["leadingComments", "trailingComments"];
 
+/**
+ * Description
+ *
+ * @param {Object} child
+ * @returns {Object} child
+ */
+
 t.removeComments = function (child) {
   _.each(t.COMMENT_KEYS, function (key) {
     delete child[key];
@@ -300,6 +477,14 @@ t.removeComments = function (child) {
   return child;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} child
+ * @param {Object} parent
+ * @returns {Object} child
+ */
+
 t.inheritsComments = function (child, parent) {
   _.each(t.COMMENT_KEYS, function (key) {
     child[key]  = _.uniq(_.compact([].concat(child[key], parent[key])));
@@ -307,7 +492,13 @@ t.inheritsComments = function (child, parent) {
   return child;
 };
 
-//
+/**
+ * Description
+ *
+ * @param {Object} child
+ * @param {Object} parent
+ * @returns {Object} child
+ */
 
 t.inherits = function (child, parent) {
   child.loc   = parent.loc;
@@ -318,10 +509,24 @@ t.inherits = function (child, parent) {
   return child;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} specifier
+ * @returns {String}
+ */
+
 t.getSpecifierName = function (specifier) {
   return specifier.name || specifier.id;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} specifier
+ * @returns {Boolean}
+ */
+
 t.isSpecifierDefault = function (specifier) {
   return t.isIdentifier(specifier.id) && specifier.id.name === "default";
 };

lib/6to5/util.js

@@ -52,22 +52,6 @@ exports.arrayify = function (val) {
   throw new TypeError("illegal type for arrayify");
 };
 
-exports.getUid = function (parent, file) {
-  var node;
-
-  if (t.isAssignmentExpression(parent)) {
-    node = parent.left;
-  } else if (t.isVariableDeclarator(parent)) {
-    node = parent.id;
-  }
-
-  var id = "ref";
-
-  if (t.isIdentifier(node)) id = node.name;
-
-  return file.generateUidIdentifier(id);
-};
-
 exports.isAbsolute = function (loc) {
   if (!loc) return false;
   if (loc[0] === "/") return true; // unix

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.4.0",
+  "version": "2.4.6",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -35,7 +35,7 @@
     "test": "make test"
   },
   "dependencies": {
-    "acorn-6to5": "0.11.1-1",
+    "acorn-6to5": "0.11.1-3",
     "ast-types": "~0.6.1",
     "chokidar": "0.11.1",
     "commander": "2.5.0",

test/fixtures/generation/comments/computed-property-comments-2/expected.js

@@ -6,5 +6,6 @@ var test = {
   [( /*
       * Inside bracket init
       */
-  "b")]: "2"
+    "b"
+  )]: "2"
 }, ok = 42;

test/fixtures/generation/comments/computed-property-comments/expected.js

@@ -7,7 +7,8 @@ var test = {
   [( /*
       * Inside bracket init
       */
-  "b")]: "2",
+    "b"
+  )]: "2",
 
   ["c"
   /*
@@ -18,8 +19,9 @@ var test = {
   ["d"]: "4",
 
   [(
-  // Inside bracket, line comment
-  "e")]: "5",
+    // Inside bracket, line comment
+    "e"
+  )]: "5",
 
   ["f"
   // After bracket, line comment

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

@@ -14,32 +14,32 @@ var _inherits = function (child, parent) {
 };
 
 var Test = (function () {
-  var _TestSuper = Foo;
+  var _Foo = Foo;
   var Test = function Test() {
     woops["super"].test();
-    _TestSuper.call(this);
-    _TestSuper.prototype.test.call(this);
-    foob(_TestSuper);
+    _Foo.call(this);
+    _Foo.prototype.test.call(this);
+    foob(_Foo);
 
-    _TestSuper.call.apply(_TestSuper, [this].concat(_slice.call(arguments)));
-    _TestSuper.call.apply(_TestSuper, [this, "test"].concat(_slice.call(arguments)));
+    _Foo.call.apply(_Foo, [this].concat(_slice.call(arguments)));
+    _Foo.call.apply(_Foo, [this, "test"].concat(_slice.call(arguments)));
 
-    _TestSuper.prototype.test.call.apply(_TestSuper.prototype, [this].concat(_slice.call(arguments)));
-    _TestSuper.prototype.test.call.apply(_TestSuper.prototype, [this, "test"].concat(_slice.call(arguments)));
+    _Foo.prototype.test.call.apply(_Foo.prototype.test, [this].concat(_slice.call(arguments)));
+    _Foo.prototype.test.call.apply(_Foo.prototype.test, [this, "test"].concat(_slice.call(arguments)));
   };
 
-  _inherits(Test, _TestSuper);
+  _inherits(Test, _Foo);
 
   Test.prototype.test = function () {
-    _TestSuper.prototype.test.call(this);
-    _TestSuper.prototype.test.call.apply(_TestSuper.prototype.test, [this].concat(_slice.call(arguments)));
-    _TestSuper.prototype.test.call.apply(_TestSuper.prototype.test, [this, "test"].concat(_slice.call(arguments)));
+    _Foo.prototype.test.call(this);
+    _Foo.prototype.test.call.apply(_Foo.prototype.test, [this].concat(_slice.call(arguments)));
+    _Foo.prototype.test.call.apply(_Foo.prototype.test, [this, "test"].concat(_slice.call(arguments)));
   };
 
   Test.foo = function () {
-    _TestSuper.foo.call(this);
-    _TestSuper.foo.call.apply(_TestSuper.foo, [this].concat(_slice.call(arguments)));
-    _TestSuper.foo.call.apply(_TestSuper.foo, [this, "test"].concat(_slice.call(arguments)));
+    _Foo.foo.call(this);
+    _Foo.foo.call.apply(_Foo.foo, [this].concat(_slice.call(arguments)));
+    _Foo.foo.call.apply(_Foo.foo, [this, "test"].concat(_slice.call(arguments)));
   };
 
   return Test;

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

@@ -13,13 +13,13 @@ var _inherits = function (child, parent) {
 };
 
 var Test = (function () {
-  var _TestSuper = Foo;
+  var _Foo = Foo;
   var Test = function Test() {
-    _TestSuper.prototype.test;
-    _TestSuper.prototype.test.whatever;
+    _Foo.prototype.test;
+    _Foo.prototype.test.whatever;
   };
 
-  _inherits(Test, _TestSuper);
+  _inherits(Test, _Foo);
 
   return Test;
 })();

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

@@ -13,16 +13,16 @@ var _inherits = function (child, parent) {
 };
 
 var Test = (function () {
-  var _TestSuper = Foo;
+  var _Foo = Foo;
   var Test = function Test() {
-    _TestSuper.prototype.test.whatever();
-    _TestSuper.prototype.test.call(this);
+    _Foo.prototype.test.whatever();
+    _Foo.prototype.test.call(this);
   };
 
-  _inherits(Test, _TestSuper);
+  _inherits(Test, _Foo);
 
   Test.test = function () {
-    return _TestSuper.wow.call(this);
+    return _Foo.wow.call(this);
   };
 
   return Test;

test/fixtures/transformation/es6-classes/constructor/expected.js

@@ -17,12 +17,12 @@ var Test = function Test() {
 };
 
 var Foo = (function () {
-  var _FooSuper = Bar;
+  var _Bar = Bar;
   var Foo = function Foo() {
     this.state = "test";
   };
 
-  _inherits(Foo, _FooSuper);
+  _inherits(Foo, _Bar);
 
   return Foo;
 })();

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

@@ -13,27 +13,27 @@ var _inherits = function (child, parent) {
 };
 
 var BaseController = (function () {
-  var _BaseControllerSuper = Chaplin.Controller;
+  var _Chaplin$Controller = Chaplin.Controller;
   var BaseController = function BaseController() {
-    if (_BaseControllerSuper) {
-      _BaseControllerSuper.apply(this, arguments);
+    if (_Chaplin$Controller) {
+      _Chaplin$Controller.apply(this, arguments);
     }
   };
 
-  _inherits(BaseController, _BaseControllerSuper);
+  _inherits(BaseController, _Chaplin$Controller);
 
   return BaseController;
 })();
 
 var BaseController2 = (function () {
-  var _BaseController2Super = Chaplin.Controller.Another;
+  var _Chaplin$Controller$Another = Chaplin.Controller.Another;
   var BaseController2 = function BaseController2() {
-    if (_BaseController2Super) {
-      _BaseController2Super.apply(this, arguments);
+    if (_Chaplin$Controller$Another) {
+      _Chaplin$Controller$Another.apply(this, arguments);
     }
   };
 
-  _inherits(BaseController2, _BaseController2Super);
+  _inherits(BaseController2, _Chaplin$Controller$Another);
 
   return BaseController2;
 })();

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

@@ -13,14 +13,14 @@ var _inherits = function (child, parent) {
 };
 
 var Test = (function () {
-  var _TestSuper = Foo;
+  var _Foo = Foo;
   var Test = function Test() {
-    if (_TestSuper) {
-      _TestSuper.apply(this, arguments);
+    if (_Foo) {
+      _Foo.apply(this, arguments);
     }
   };
 
-  _inherits(Test, _TestSuper);
+  _inherits(Test, _Foo);
 
   return Test;
 })();

test/fixtures/transformation/es6-constants/destructuring/expected.js

@@ -24,15 +24,15 @@ var a = _ref2[0];
 var b = _ref2[1];
 var _ref3 = [3, 4];
 
-var _ref4 = _slicedToArray(_ref3, 2);
+var _ref3 = _slicedToArray(_ref3, 2);
 
-var c = _ref4[0];
-var d = _ref4[1];
-var _ref5 = { e: 5, f: 6 };
+var c = _ref3[0];
+var d = _ref3[1];
+var _ref4 = { e: 5, f: 6 };
 
-var e = _ref5.e;
-var f = _ref5.f;
-var _ref6 = { a: 7, b: 8 };
+var e = _ref4.e;
+var f = _ref4.f;
+var _ref5 = { a: 7, b: 8 };
 
-var g = _ref6.a;
-var h = _ref6.b;
+var g = _ref5.a;
+var h = _ref5.b;

test/fixtures/transformation/es6-destructuring/array/expected.js

@@ -21,10 +21,10 @@ var _ref = ["hello", [", ", "junk"], ["world"]];
 var _ref2 = _slicedToArray(_ref, 4);
 
 var a = _ref2[0];
-var _ref3 = _slicedToArray(_ref2[1], 1);
+var _ref2$1 = _slicedToArray(_ref2[1], 1);
 
-var b = _ref3[0];
-var _ref4 = _slicedToArray(_ref2[2], 1);
+var b = _ref2$1[0];
+var _ref2$2 = _slicedToArray(_ref2[2], 1);
 
-var c = _ref4[0];
+var c = _ref2$2[0];
 var d = _ref2[3];

test/fixtures/transformation/es6-destructuring/assignment-expression/expected.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var _temp, _ref;
+var _temp, _temp2;
 var _slicedToArray = function (arr, i) {
   if (Array.isArray(arr)) {
     return arr;
@@ -17,4 +17,4 @@ var _slicedToArray = function (arr, i) {
   }
 };
 
-console.log((_temp = [123], _ref = _slicedToArray(_temp, 1), x = _ref[0], _temp));
+console.log((_temp = [123], _temp2 = _slicedToArray(_temp, 1), x = _temp2[0], _temp));

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

@@ -21,10 +21,10 @@ var _ref = ["foo", "hello", [", ", "junk"], ["world"]];
 var _ref2 = _slicedToArray(_ref, 5);
 
 var a = _ref2[1];
-var _ref3 = _slicedToArray(_ref2[2], 1);
+var _ref2$2 = _slicedToArray(_ref2[2], 1);
 
-var b = _ref3[0];
-var _ref4 = _slicedToArray(_ref2[3], 1);
+var b = _ref2$2[0];
+var _ref2$3 = _slicedToArray(_ref2[3], 1);
 
-var c = _ref4[0];
+var c = _ref2$3[0];
 var d = _ref2[4];

test/fixtures/transformation/es6-destructuring/mixed/expected.js

@@ -16,11 +16,11 @@ var _slicedToArray = function (arr, i) {
   }
 };
 
-var _ref = _slicedToArray(rect.topLeft, 2);
+var _rect$topLeft = _slicedToArray(rect.topLeft, 2);
 
-var x1 = _ref[0];
-var y1 = _ref[1];
-var _ref2 = _slicedToArray(rect.bottomRight, 2);
+var x1 = _rect$topLeft[0];
+var y1 = _rect$topLeft[1];
+var _rect$bottomRight = _slicedToArray(rect.bottomRight, 2);
 
-var x2 = _ref2[0];
-var y2 = _ref2[1];
+var x2 = _rect$bottomRight[0];
+var y2 = _rect$bottomRight[1];

test/fixtures/transformation/es6-destructuring/parameters/expected.js

@@ -31,17 +31,17 @@ function unpackObject(_ref2) {
 
 console.log(unpackObject({ title: "title", author: "author" }));
 
-var unpackArray = function (_ref3, _ref5) {
-  var _ref4 = _slicedToArray(_ref3, 3);
+var unpackArray = function (_ref3, _ref4) {
+  var _ref3 = _slicedToArray(_ref3, 3);
 
-  var a = _ref4[0];
-  var b = _ref4[1];
-  var c = _ref4[2];
-  var _ref6 = _slicedToArray(_ref5, 3);
+  var a = _ref3[0];
+  var b = _ref3[1];
+  var c = _ref3[2];
+  var _ref4 = _slicedToArray(_ref4, 3);
 
-  var x = _ref6[0];
-  var y = _ref6[1];
-  var z = _ref6[2];
+  var x = _ref4[0];
+  var y = _ref4[1];
+  var z = _ref4[2];
   return a + b + c;
 };
 

test/fixtures/transformation/es7-array-comprehension/arguments/expected.js

@@ -3,14 +3,14 @@
 function add() {
   var _arguments = arguments;
   return (function () {
-    var _arr = [];
+    var _ref = [];
 
     for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
       var i = _step.value;
-      _arr.push(i * _arguments[0]);
+      _ref.push(i * _arguments[0]);
     }
 
-    return _arr;
+    return _ref;
   })();
 }
 

test/fixtures/transformation/es7-array-comprehension/multiple-if/expected.js

@@ -1,17 +1,17 @@
 "use strict";
 
 var seattlers = (function () {
-  var _arr = [];
+  var _seattlers = [];
 
   for (var _iterator = countries[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
     var customers = _step.value;
     for (var _iterator2 = customers[Symbol.iterator](), _step2; !(_step2 = _iterator2.next()).done;) {
       var c = _step2.value;
       if (c.city == "Seattle") {
-        _arr.push({ name: c.name, age: c.age });
+        _seattlers.push({ name: c.name, age: c.age });
       }
     }
   }
 
-  return _arr;
+  return _seattlers;
 })();

test/fixtures/transformation/es7-array-comprehension/this/expected.js

@@ -3,14 +3,14 @@
 function add() {
   var _this = this;
   return (function () {
-    var _arr = [];
+    var _ref = [];
 
     for (var _iterator = [1, 2, 3][Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
       var i = _step.value;
-      _arr.push(i * _this.multiplier);
+      _ref.push(i * _this.multiplier);
     }
 
-    return _arr;
+    return _ref;
   })();
 }
 

test/fixtures/transformation/optional-async-to-generator/statement/actual.js

@@ -0,0 +1,3 @@
+async function foo() {
+  var wat = await bar();
+}

test/fixtures/transformation/optional-async-to-generator/statement/expected.js

@@ -0,0 +1,42 @@
+"use strict";
+
+var _asyncToGenerator = function (fn) {
+  return function () {
+    var gen = fn.apply(this, arguments);
+
+    return new Promise(function (resolve, reject) {
+      function step(getNext) {
+        var next;
+        try {
+          next = getNext();
+        } catch (e) {
+          reject(e);
+
+          return;
+        }
+        if (next.done) {
+          resolve(next.value);
+
+          return;
+        }
+        Promise.resolve(next.value).then(function (v) {
+          step(function () {
+            return gen.next(v);
+          });
+        }, function (e) {
+          step(function () {
+            return gen["throw"](e);
+          });
+        });
+      }
+
+      step(function () {
+        return gen.next();
+      });
+    });
+  };
+};
+
+var foo = _asyncToGenerator(function* foo() {
+  var wat = yield bar();
+});

test/fixtures/transformation/optional-bluebird-coroutines/statement/actual.js

@@ -0,0 +1,3 @@
+async function foo() {
+  var wat = await bar();
+}

test/fixtures/transformation/optional-bluebird-coroutines/statement/expected.js

@@ -0,0 +1,11 @@
+"use strict";
+
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+var Bluebird = _interopRequire(require("bluebird"));
+
+var foo = Bluebird.coroutine(function* foo() {
+  var wat = yield bar();
+});

test/fixtures/transformation/optional-core-aliasing/es6-destructuring/expected.js

@@ -27,10 +27,10 @@ var _ref = ["hello", [", ", "junk"], ["world"]];
 var _ref2 = _slicedToArray(_ref, 4);
 
 var a = _ref2[0];
-var _ref3 = _slicedToArray(_ref2[1], 1);
+var _ref2$1 = _slicedToArray(_ref2[1], 1);
 
-var b = _ref3[0];
-var _ref4 = _slicedToArray(_ref2[2], 1);
+var b = _ref2$1[0];
+var _ref2$2 = _slicedToArray(_ref2[2], 1);
 
-var c = _ref4[0];
+var c = _ref2$2[0];
 var d = _ref2[3];

test/fixtures/transformation/playground/memoization-assignment-operator/expected.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var _propKey2, _obj2, _propKey4;
+var _ref2, _obj2, _ref4;
 var _hasOwn = Object.prototype.hasOwnProperty;
 var obj = {};
 
@@ -9,17 +9,17 @@ if (!_hasOwn.call(obj, "x")) obj.x = 2;
 
 console.log((!_hasOwn.call(obj, "x") && (obj.x = 2), obj.x));
 
-var _propKey = x();
+var _ref = x();
 
-if (!_hasOwn.call(obj, _propKey)) obj[_propKey] = 2;
+if (!_hasOwn.call(obj, _ref)) obj[_ref] = 2;
 
 
-console.log((_propKey2 = x(), !_hasOwn.call(obj, _propKey2) && (obj[_propKey2] = 2), obj[_propKey2]));
+console.log((_ref2 = x(), !_hasOwn.call(obj, _ref2) && (obj[_ref2] = 2), obj[_ref2]));
 
 var _obj = obj[y()];
-var _propKey3 = x();
+var _ref3 = x();
 
-if (!_hasOwn.call(_obj, _propKey3)) _obj[_propKey3] = 2;
+if (!_hasOwn.call(_obj, _ref3)) _obj[_ref3] = 2;
 
 
-console.log((_obj2 = obj[y()], _propKey4 = x(), !_hasOwn.call(_obj2, _propKey4) && (_obj2[_propKey4] = 2), _obj2[_propKey4]));
+console.log((_obj2 = obj[y()], _ref4 = x(), !_hasOwn.call(_obj2, _ref4) && (_obj2[_ref4] = 2), _obj2[_ref4]));

test/types.js

@@ -0,0 +1,55 @@
+var assert = require("assert");
+var t      = require("../lib/6to5/types");
+
+suite("types", function () {
+  test("isFalsyExpression", function () {
+    assert.ok(t.isFalsyExpression(t.literal("")));
+    assert.ok(t.isFalsyExpression(t.literal(null)));
+    assert.ok(t.isFalsyExpression(t.literal(0)));
+    assert.ok(t.isFalsyExpression(t.identifier("undefined")));
+
+    assert.ok(!t.isFalsyExpression(t.literal("foobar")));
+    assert.ok(!t.isFalsyExpression(t.literal(5)));
+    assert.ok(!t.isFalsyExpression(t.identifier("foobar")));
+  });
+
+  test("toSequenceExpression");
+
+  test("shallowEqual");
+
+  test("appendToMemberExpression");
+
+  test("prependToMemberExpression");
+
+  test("isDynamic");
+
+  test("isReferenced");
+
+  test("isValidIdentifier");
+
+  test("toIdentifier");
+
+  test("ensureBlock");
+
+  test("toStatement");
+
+  test("toBlock");
+
+  test("getUid");
+
+  test("getIds");
+
+  test("isLet");
+
+  test("isVar");
+
+  test("removeComments");
+
+  test("inheritsComments");
+
+  test("inherits");
+
+  test("getSpecifierName");
+
+  test("isSpecifierDefault");
+});