v4.6.6

More es6

CHANGELOG.md

@@ -13,6 +13,33 @@ _Note: Gaps between patch versions are faulty/broken releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 4.6.6
+
+ * **Bug Fix**
+  * Fix incorrect method call in `utility.deadCodeElimination` transformer.
+  * Fix `es6.blockScopingTDZ` transformer duplicating binding nodes.
+
+## 4.6.5
+
+ * **Internal**
+  * `useStrict` transformer has been renamed to `strict`.
+
+## 4.6.4
+
+ * **Bug Fix**
+  * Fix `ForOfStatement` not proplery inheriting labels.
+  * When in closure mode in block scoping transformer, properly check for variable shadowing.
+ * **New Feature**
+  * New `utility.inlineEnvironmentVariables` and `utility.inlineExpression` transformers.
+
+## 4.6.3
+
+ * **Bug Fix**
+  * Fix `arguments` being incorrectly aliased in arrow function rest parameter optimisation.
+  * Make deoptimisation trigger safer.
+ * **New Feature**
+  * Flow types are now retained when blacklisting the `flow` transformer.
+
 ## 4.6.1
 
  * **Bug Fix**

CONTRIBUTING.md

@@ -53,7 +53,6 @@ $ mocha test/transformation.js
 #### Code Standards
 
  * **General**
-   * No ES6 syntax features or methods, exclusively ES5.
    * Max of five arguments for functions
    * Max depth of four nested blocks
    * 2-spaced soft tabs

bin/babel/dir.js

@@ -31,6 +31,14 @@ module.exports = function (commander, filenames, opts) {
     console.log(src + " -> " + dest);
   };
 
+  var handleFile = function (src, filename) {
+    if (util.canCompile(filename)) {
+      write(src, filename);
+    } else if (commander.copyFiles) {
+      outputFileSync(path.join(commander.outDir, filename), fs.readFileSync(src));
+    }
+  };
+
   var handle = function (filename) {
     if (!fs.existsSync(filename)) return;
 
@@ -41,11 +49,7 @@ module.exports = function (commander, filenames, opts) {
 
       _.each(util.readdir(dirname), function (filename) {
         var src = path.join(dirname, filename);
-        if (util.canCompile(filename)) {
-          write(src, filename);
-        } else if (commander.copyFiles) {
-          outputFileSync(path.join(commander.outDir, filename), fs.readFileSync(src));
-        }
+        handleFile(src, filename);
       });
     } else {
       write(filename, filename);
@@ -65,7 +69,7 @@ module.exports = function (commander, filenames, opts) {
         watcher.on(type, function (filename) {
           var relative = path.relative(dirname, filename) || filename;
           try {
-            if (util.canCompile(filename)) write(filename, relative);
+            handleFile(filename, relative);
           } catch (err) {
             console.error(err.stack);
           }

package.json

@@ -1,7 +1,7 @@
 {
   "name": "babel",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "4.6.1",
+  "version": "4.6.6",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "repository": "babel/babel",
@@ -36,7 +36,7 @@
     "test": "make test"
   },
   "dependencies": {
-    "acorn-babel": "0.11.1-35",
+    "acorn-babel": "0.11.1-37",
     "ast-types": "~0.6.1",
     "chalk": "^1.0.0",
     "chokidar": "^0.12.6",
@@ -57,7 +57,7 @@
     "path-is-absolute": "^1.0.0",
     "private": "^0.1.6",
     "regenerator-babel": "0.8.13-1",
-    "regexpu": "^1.1.1",
+    "regexpu": "^1.1.2",
     "repeating": "^1.1.2",
     "shebang-regex": "^1.0.0",
     "slash": "^1.0.0",

packages/babel-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "babel-runtime",
   "description": "babel selfContained runtime",
-  "version": "4.6.0",
+  "version": "4.6.5",
   "repository": "babel/babel",
   "author": "Sebastian McKenzie <sebmck@gmail.com>"
 }

src/babel/api/browser.js

@@ -25,7 +25,7 @@ transform.load = function (url, callback, opts = {}, hold) {
       if (!hold) transform.run.apply(transform, param);
       if (callback) callback(param);
     } else {
-      throw new Error("Could not load " + url);
+      throw new Error(`Could not load ${url}`);
     }
   };
 

src/babel/api/register/node.js

@@ -46,7 +46,7 @@ var compile = function (filename) {
   var opts = extend({}, transformOpts);
   resolveRc(filename, opts);
 
-  var cacheKey = filename + ":" + JSON.stringify(opts);
+  var cacheKey = `${filename}:${JSON.stringify(opts)}`;
 
   if (cache) {
     var cached = cache[cacheKey];

src/babel/api/register/resolve-rc.js

@@ -23,7 +23,7 @@ export default function (loc, opts = {}) {
       try {
         json = JSON.parse(content);
       } catch (err) {
-        err.message = file + ": " + err.message;
+        err.message = `${file}: ${err.message}`;
         throw err;
       }
 

src/babel/generation/buffer.js

@@ -140,7 +140,7 @@ export default class Buffer {
       var indent = this.getIndent();
 
       // replace all newlines with newlines with the indentation
-      str = str.replace(/\n/g, "\n" + indent);
+      str = str.replace(/\n/g, `\n${indent}`);
 
       // we've got a newline before us so prepend on the indentation
       if (this.isLast("\n")) this._push(indent);

src/babel/generation/generators/classes.js

@@ -1,5 +1,4 @@
-exports.ClassExpression =
-exports.ClassDeclaration = function (node, print) {
+export function ClassDeclaration(node, print) {
   this.push("class");
 
   if (node.id) {
@@ -7,14 +6,24 @@ exports.ClassDeclaration = function (node, print) {
     print(node.id);
   }
 
+  print(node.typeParameters);
+
   if (node.superClass) {
     this.push(" extends ");
     print(node.superClass);
+    print(node.superTypeParameters);
+  }
+
+  if (node.implements) {
+    this.push(" implements ");
+    print.join(node.implements, { separator: ", " });
   }
 
   this.space();
   print(node.body);
-};
+}
+
+export { ClassDeclaration as ClassExpression };
 
 export function ClassBody(node, print) {
   if (node.body.length === 0) {

src/babel/generation/generators/expressions.js

@@ -109,16 +109,19 @@ export function ExpressionStatement(node, print) {
   this.semicolon();
 }
 
-exports.BinaryExpression =
-exports.LogicalExpression =
-exports.AssignmentPattern =
-exports.AssignmentExpression = function (node, print) {
+export function AssignmentExpression(node, print) {
   // todo: add cases where the spaces can be dropped when in compact mode
   print(node.left);
   this.push(" ");
   this.push(node.operator);
   this.push(" ");
   print(node.right);
+}
+
+export {
+  AssignmentExpression as BinaryExpression,
+  AssignmentExpression as LogicalExpression,
+  AssignmentExpression as AssignmentPattern
 };
 
 var SCIENTIFIC_NOTATION = /e/i;

src/babel/generation/generators/flow.js

@@ -1,34 +1,226 @@
-exports.AnyTypeAnnotation =
-exports.ArrayTypeAnnotation =
-exports.BooleanTypeAnnotation =
-exports.ClassProperty =
-exports.DeclareClass =
-exports.DeclareFunction =
-exports.DeclareModule =
-exports.DeclareVariable =
-exports.FunctionTypeAnnotation =
-exports.FunctionTypeParam =
-exports.GenericTypeAnnotation =
-exports.InterfaceExtends =
-exports.InterfaceDeclaration =
-exports.IntersectionTypeAnnotation =
-exports.NullableTypeAnnotation =
-exports.NumberTypeAnnotation =
-exports.StringLiteralTypeAnnotation =
-exports.StringTypeAnnotation =
-exports.TupleTypeAnnotation =
-exports.TypeofTypeAnnotation =
-exports.TypeAlias =
-exports.TypeAnnotation =
-exports.TypeParameterDeclaration =
-exports.TypeParameterInstantiation =
-exports.ObjectTypeAnnotation =
-exports.ObjectTypeCallProperty =
-exports.ObjectTypeIndexer =
-exports.ObjectTypeProperty =
-exports.QualifiedTypeIdentifier =
-exports.UnionTypeAnnotation =
-exports.TypeCastExpression =
-exports.VoidTypeAnnotation = function () {
-  // todo: implement these once we have a `--keep-types` option
-};
+import t from "../../types";
+
+export function AnyTypeAnnotation() {
+  this.push("any");
+}
+
+export function ArrayTypeAnnotation(node, print) {
+  print(node.elementType);
+  this.push("[");
+  this.push("]");
+}
+
+export function BooleanTypeAnnotation(node) {
+  this.push("bool");
+}
+
+export function ClassProperty(node, print) {
+  if (node.static) this.push("static ");
+  print(node.key);
+  print(node.typeAnnotation);
+  this.semicolon();
+}
+
+export function DeclareClass(node, print) {
+  this.push("declare class ");
+  this._interfaceish(node, print);
+}
+
+export function DeclareFunction(node, print) {
+  this.push("declare function ");
+  print(node.id);
+  print(node.id.typeAnnotation.typeAnnotation);
+  this.semicolon();
+}
+
+export function DeclareModule(node, print) {
+  this.push("declare module ");
+  print(node.id);
+  this.space();
+  print(node.body);
+}
+
+export function DeclareVariable(node, print) {
+  this.push("declare var ");
+  print(node.id);
+  print(node.id.typeAnnotation);
+  this.semicolon();
+}
+
+export function FunctionTypeAnnotation(node, print, parent) {
+  print(node.typeParameters);
+  this.push("(");
+  print.list(node.params);
+
+  if (node.rest) {
+    if (node.params.length) {
+      this.push(",");
+      this.space();
+    }
+    this.push("...");
+    print(node.rest);
+  }
+
+  this.push(")");
+
+  // this node type is overloaded, not sure why but it makes it EXTREMELY annoying
+  if (parent.type === "ObjectTypeProperty" || parent.type === "ObjectTypeCallProperty" || parent.type === "DeclareFunction") {
+    this.push(":");
+  } else {
+    this.space();
+    this.push("=>");
+  }
+
+  this.space();
+  print(node.returnType);
+}
+
+export function FunctionTypeParam(node, print) {
+  print(node.name);
+  if (node.optional) this.push("?");
+  this.push(":");
+  this.space();
+  print(node.typeAnnotation);
+}
+
+export function InterfaceExtends(node, print) {
+  print(node.id);
+  print(node.typeParameters);
+}
+
+export { InterfaceExtends as ClassImplements, InterfaceExtends as GenericTypeAnnotation };
+
+export function _interfaceish(node, print) {
+  print(node.id);
+  print(node.typeParameters);
+  if (node.extends.length) {
+    this.push(" extends ");
+    print.join(node.extends, { separator: ", " });
+  }
+  this.space();
+  print(node.body);
+}
+
+export function InterfaceDeclaration(node, print) {
+  this.push("interface ");
+  this._interfaceish(node, print);
+}
+
+export function IntersectionTypeAnnotation(node, print) {
+  print.join(node.types, { separator: " & " });
+}
+
+export function NullableTypeAnnotation(node, print) {
+  this.push("?");
+  print(node.typeAnnotation);
+}
+
+export function NumberTypeAnnotation() {
+  this.push("number");
+}
+
+export function StringLiteralTypeAnnotation(node) {
+  this._stringLiteral(node.value);
+}
+
+export function StringTypeAnnotation() {
+  this.push("string");
+}
+
+export function TupleTypeAnnotation(node, print) {
+  this.push("[");
+  print.join(node.types, { separator: ", " });
+  this.push("]");
+}
+
+export function TypeofTypeAnnotation(node, print) {
+  this.push("typeof ");
+  print(node.argument);
+}
+
+export function TypeAlias(node, print) {
+  this.push("type ");
+  print(node.id);
+  print(node.typeParameters);
+  this.space();
+  this.push("=");
+  this.space();
+  print(node.right);
+  this.semicolon();
+}
+
+export function TypeAnnotation(node, print) {
+  this.push(":");
+  this.space();
+  if (node.optional) this.push("?");
+  print(node.typeAnnotation);
+}
+
+export function TypeParameterInstantiation(node, print) {
+  this.push("<");
+  print.join(node.params, { separator: ", " });
+  this.push(">");
+}
+
+export { TypeParameterInstantiation as TypeParameterDeclaration };
+
+export function ObjectTypeAnnotation(node, print) {
+  this.push("{");
+  var props = node.properties.concat(node.callProperties, node.indexers);
+  if (props.length) {
+    this.space();
+    print.list(props, { indent: true, separator: "; " });
+    this.space();
+  }
+  this.push("}");
+}
+
+export function ObjectTypeCallProperty(node, print) {
+  if (node.static) this.push("static ");
+  print(node.value);
+}
+
+export function ObjectTypeIndexer(node, print) {
+  if (node.static) this.push("static ");
+  this.push("[");
+  print(node.id);
+  this.push(":");
+  this.space();
+  print(node.key);
+  this.push("]");
+  this.push(":");
+  this.space();
+  print(node.value);
+}
+
+export function ObjectTypeProperty(node, print) {
+  if (node.static) this.push("static ");
+  print(node.key);
+  if (node.optional) this.push("?");
+  if (!t.isFunctionTypeAnnotation(node.value)) {
+    this.push(":");
+    this.space();
+  }
+  print(node.value);
+}
+
+export function QualifiedTypeIdentifier(node, print) {
+  print(node.qualification);
+  this.push(".");
+  print(node.id);
+}
+
+export function UnionTypeAnnotation(node, print) {
+  print.join(node.types, { separator: " | " });
+}
+
+export function TypeCastExpression(node, print) {
+  this.push("(");
+  print(node.expression);
+  print(node.typeAnnotation);
+  this.push(")");
+}
+
+export function VoidTypeAnnotation(node) {
+  this.push("void");
+}

src/babel/generation/generators/methods.js

@@ -1,9 +1,19 @@
 import t from "../../types";
 
 export function _params(node, print) {
+  print(node.typeParameters);
   this.push("(");
-  print.list(node.params);
+  print.list(node.params, {
+    iterator: (node) =>{
+      if (node.optional) this.push("?");
+      print(node.typeAnnotation);
+    }
+  });
   this.push(")");
+
+  if (node.returnType) {
+    print(node.returnType);
+  }
 }
 
 export function _method(node, print) {
@@ -34,8 +44,7 @@ export function _method(node, print) {
   print(value.body);
 }
 
-exports.FunctionDeclaration =
-exports.FunctionExpression = function (node, print) {
+export function FunctionExpression(node, print) {
   if (node.async) this.push("async ");
   this.push("function");
   if (node.generator) this.push("*");
@@ -50,7 +59,9 @@ exports.FunctionExpression = function (node, print) {
   this._params(node, print);
   this.space();
   print(node.body);
-};
+}
+
+export { FunctionExpression as FunctionDeclaration };
 
 export function ArrowFunctionExpression(node, print) {
   if (node.async) this.push("async ");

src/babel/generation/generators/modules.js

@@ -5,7 +5,7 @@ export function ImportSpecifier(node, print) {
   if (t.isSpecifierDefault(node)) {
     print(t.getSpecifierName(node));
   } else {
-    return exports.ExportSpecifier.apply(this, arguments);
+    return ExportSpecifier.apply(this, arguments);
   }
 }
 

src/babel/generation/generators/playground.js

@@ -2,6 +2,6 @@ import each from "lodash/collection/each";
 
 each(["BindMemberExpression", "BindFunctionExpression"], function (type) {
   exports[type] = function () {
-    throw new ReferenceError("Trying to render non-standard playground node " + JSON.stringify(type));
+    throw new ReferenceError(`Trying to render non-standard playground node ${JSON.stringify(type)}`);
   };
 });

src/babel/generation/generators/statements.js

@@ -60,7 +60,7 @@ var buildForXStatement = function (op) {
     this.keyword("for");
     this.push("(");
     print(node.left);
-    this.push(" " + op + " ");
+    this.push(` ${op} `);
     print(node.right);
     this.push(")");
     print.block(node.body);
@@ -192,7 +192,7 @@ export function VariableDeclaration(node, print, parent) {
 
   var sep = ",";
   if (!this.format.compact && hasInits) {
-    sep += "\n" + repeating(" ", node.kind.length + 1);
+    sep += `\n${repeating(" ", node.kind.length + 1)}`;
   } else {
     sep += " ";
   }
@@ -211,13 +211,12 @@ export function PrivateDeclaration(node, print) {
 }
 
 export function VariableDeclarator(node, print) {
+  print(node.id);
+  print(node.id.typeAnnotation);
   if (node.init) {
-    print(node.id);
     this.space();
     this.push("=");
     this.space();
     print(node.init);
-  } else {
-    print(node.id);
   }
 }

src/babel/generation/generators/types.js

@@ -4,12 +4,12 @@ export function Identifier(node) {
   this.push(node.name);
 }
 
-exports.RestElement =
-exports.SpreadElement =
-exports.SpreadProperty = function (node, print) {
+export function RestElement(node, print) {
   this.push("...");
   print(node.argument);
-};
+}
+
+export { RestElement as SpreadElement, RestElement as SpreadProperty };
 
 export function VirtualPropertyExpression(node, print) {
   print(node.object);
@@ -17,8 +17,7 @@ export function VirtualPropertyExpression(node, print) {
   print(node.property);
 }
 
-exports.ObjectExpression =
-exports.ObjectPattern = function (node, print) {
+export function ObjectExpression(node, print) {
   var props = node.properties;
 
   if (props.length) {
@@ -32,7 +31,9 @@ exports.ObjectPattern = function (node, print) {
   } else {
     this.push("{}");
   }
-};
+}
+
+export { ObjectExpression as ObjectPattern };
 
 export function Property(node, print) {
   if (node.method || node.kind === "get" || node.kind === "set") {
@@ -53,8 +54,7 @@ export function Property(node, print) {
   }
 }
 
-exports.ArrayExpression =
-exports.ArrayPattern = function (node, print) {
+export function ArrayExpression(node, print) {
   var elems = node.elements;
   var len   = elems.length;
 
@@ -76,28 +76,34 @@ exports.ArrayPattern = function (node, print) {
   });
 
   this.push("]");
-};
+}
+
+export { ArrayExpression as ArrayPattern };
 
 export function Literal(node) {
   var val  = node.value;
   var type = typeof val;
 
   if (type === "string") {
-    val = JSON.stringify(val);
-
-    // escape illegal js but valid json unicode characters
-    val = val.replace(/[\u000A\u000D\u2028\u2029]/g, function (c) {
-      return "\\u" + ("0000" + c.charCodeAt(0).toString(16)).slice(-4);
-    });
-
-    this.push(val);
+    this._stringLiteral(val);
   } else if (type === "number") {
     this.push(val + "");
   } else if (type === "boolean") {
     this.push(val ? "true" : "false");
   } else if (node.regex) {
-    this.push("/" + node.regex.pattern + "/" + node.regex.flags);
+    this.push(`/${node.regex.pattern}/${node.regex.flags}`);
   } else if (val === null) {
     this.push("null");
   }
 }
+
+export function _stringLiteral(val) {
+  val = JSON.stringify(val);
+
+  // escape illegal js but valid json unicode characters
+  val = val.replace(/[\u000A\u000D\u2028\u2029]/g, function (c) {
+    return "\\u" + ("0000" + c.charCodeAt(0).toString(16)).slice(-4);
+  });
+
+  this.push(val);
+}

src/babel/generation/index.js

@@ -117,7 +117,7 @@ class CodeGenerator {
   }
 
   print(node, parent, opts = {}) {
-    if (!node) return "";
+    if (!node) return;
 
     if (parent && parent._compact) {
       node._compact = true;
@@ -187,7 +187,7 @@ class CodeGenerator {
 
       this.printTrailingComments(node, parent);
     } else {
-      throw new ReferenceError("unknown node of type " + JSON.stringify(node.type) + " with constructor " + JSON.stringify(node && node.constructor.name));
+      throw new ReferenceError(`unknown node of type ${JSON.stringify(node.type)} with constructor ${JSON.stringify(node && node.constructor.name)}`);
     }
 
     this.format.concise = oldConcise;
@@ -238,9 +238,9 @@ class CodeGenerator {
   generateComment(comment) {
     var val = comment.value;
     if (comment.type === "Line") {
-      val = "//" + val;
+      val = `//${val}`;
     } else {
-      val = "/*" + val + "*/";
+      val = `/*${val}*/`;
     }
     return val;
   }
@@ -319,7 +319,7 @@ class CodeGenerator {
         }
 
         var indent = Math.max(this.indentSize(), column);
-        val = val.replace(/\n/g, "\n" + repeating(" ", indent));
+        val = val.replace(/\n/g, `\n${repeating(" ", indent)}`);
       }
 
       if (column === 0) {

src/babel/generation/node/parentheses.js

@@ -21,6 +21,12 @@ each([
   });
 });
 
+export function NullableTypeAnnotation(node, parent) {
+  return t.isArrayTypeAnnotation(parent);
+}
+
+export { NullableTypeAnnotation as FunctionTypeAnnotation };
+
 export function UpdateExpression(node, parent) {
   if (t.isMemberExpression(parent) && parent.object === node) {
     // (foo++).test()
@@ -139,8 +145,7 @@ export function FunctionExpression(node, parent) {
   }
 }
 
-exports.AssignmentExpression =
-exports.ConditionalExpression = function (node, parent) {
+export function ConditionalExpression(node, parent) {
   if (t.isUnaryLike(parent)) {
     return true;
   }
@@ -164,4 +169,6 @@ exports.ConditionalExpression = function (node, parent) {
   }
 
   return false;
-};
+}
+
+export { ConditionalExpression as AssignmentExpression };

src/babel/helpers/code-frame.js

@@ -81,8 +81,7 @@ module.exports = function (lines, lineNumber, colNumber) {
         return;
       }
       if (colNumber) {
-        params.line += "\n" + params.before + repeating(" ", params.width) +
-                       params.after + repeating(" ", colNumber - 1) + "^";
+        params.line += `\n${params.before}${repeating(" ", params.width)}${params.after}${repeating(" ", colNumber - 1)}^`;
       }
       params.before = params.before.replace(/^./, ">");
     }

src/babel/helpers/parse.js

@@ -32,7 +32,7 @@ module.exports = function (opts, code, callback) {
   } catch (err) {
     if (!err._babel) {
       err._babel = true;
-      var message = opts.filename + ": " + err.message;
+      var message = `${opts.filename}: ${err.message}`;
 
       var loc = err.loc;
       if (loc) {

src/babel/messages.js

@@ -22,14 +22,14 @@ export var messages = {
 };
 
 export function get(key) {
-  var msg = exports.messages[key];
-  if (!msg) throw new ReferenceError("Unknown message `" + key + "`");
+  var msg = messages[key];
+  if (!msg) throw new ReferenceError(`Unknown message ${JSON.stringify(key)}`);
 
   var args = [];
   for (var i = 1; i < arguments.length; i++) {
     args.push(arguments[i]);
   }
-  args = exports.parseArgs(args);
+  args = parseArgs(args);
 
   return msg.replace(/\$(\d+)/g, function (str, i) {
     return args[--i];

src/babel/transformation/file.js

@@ -20,12 +20,12 @@ var checkTransformerVisitor = {
   }
 };
 
-var checkNode = function (stack, node, scope) {
+function checkNode(stack, node, scope) {
   each(stack, function (pass) {
     if (pass.shouldRun) return;
     pass.checkNode(node, scope);
   });
-};
+}
 
 export default class File {
   constructor(opts) {
@@ -118,7 +118,7 @@ export default class File {
 
     for (var key in opts) {
       if (key[0] !== "_" && File.validOptions.indexOf(key) < 0) {
-        throw new ReferenceError("Unknown option: " + key);
+        throw new ReferenceError(`Unknown option: ${key}`);
       }
     }
 
@@ -248,7 +248,7 @@ export default class File {
 
   debug(msg) {
     var parts = this.opts.filename;
-    if (msg) parts += ": " + msg;
+    if (msg) parts += `: ${msg}`;
     util.debug(parts);
   }
 
@@ -261,7 +261,7 @@ export default class File {
     }
 
     if (!ModuleFormatter) {
-      throw new ReferenceError("Unknown module formatter type " + JSON.stringify(type));
+      throw new ReferenceError(`Unknown module formatter type ${JSON.stringify(type)}`);
     }
 
     return new ModuleFormatter(this);
@@ -338,7 +338,7 @@ export default class File {
 
   addHelper(name) {
     if (!includes(File.helpers, name)) {
-      throw new ReferenceError("Unknown helper " + name);
+      throw new ReferenceError(`Unknown helper ${name}`);
     }
 
     var program = this.ast.program;
@@ -371,7 +371,7 @@ export default class File {
 
   errorWithNode(node, msg, Error = SyntaxError) {
     var loc = node.loc.start;
-    var err = new Error("Line " + loc.line + ": " + msg);
+    var err = new Error(`Line ${loc.line}: ${msg}`);
     err.loc = loc;
     return err;
   }
@@ -388,7 +388,7 @@ export default class File {
     var opts = this.opts;
 
     opts.allowImportExportEverywhere = this.isLoose("es6.modules");
-    opts.strictMode = this.transformers.useStrict.canRun();
+    opts.strictMode = this.transformers.strict.canRun();
 
     return parse(opts, code, (tree) => {
       this.transform(tree);
@@ -430,6 +430,13 @@ export default class File {
   }
 
   checkNode(node, scope) {
+    if (Array.isArray(node)) {
+      for (var i = 0; i < node.length; i++) {
+        this.checkNode(node[i], scope);
+      }
+      return;
+    }
+
     var stack = this.transformerStack;
     scope ||= this.scope;
 
@@ -463,7 +470,7 @@ export default class File {
 
     if (this.shebang) {
       // add back shebang
-      result.code = this.shebang + "\n" + result.code;
+      result.code = `${this.shebang}\n${result.code}`;
     }
 
     if (opts.sourceMap === "inline") {

src/babel/transformation/helpers/build-react-transformer.js

@@ -6,7 +6,7 @@
 import isString from "lodash/lang/isString";
 import * as messages from "../../messages";
 import esutils from "esutils";
-import react from "./react";
+import * as react from "./react";
 import t from "../../types";
 
 module.exports = function (exports, opts) {

src/babel/transformation/helpers/define-map.js

@@ -5,12 +5,12 @@ import each from "lodash/collection/each";
 import has from "lodash/object/has";
 import t from "../../types";
 
-exports.push = function (mutatorMap, key, kind, computed, value) {
+export function push(mutatorMap, key, kind, computed, value) {
   var alias;
 
   if (t.isIdentifier(key)) {
     alias = key.name;
-    if (computed) alias = "computed:" + alias;
+    if (computed) alias = `computed:${alias}`;
   } else if (t.isLiteral(key)) {
     alias = String(key.value);
   } else {
@@ -31,9 +31,9 @@ exports.push = function (mutatorMap, key, kind, computed, value) {
   }
 
   map[kind] = value;
-};
+}
 
-exports.build = function (mutatorMap) {
+export function build(mutatorMap) {
   var objExpr = t.objectExpression([]);
 
   each(mutatorMap, function (map) {
@@ -70,4 +70,4 @@ exports.build = function (mutatorMap) {
   });
 
   return objExpr;
-};
+}

src/babel/transformation/helpers/explode-assignable-expression.js

@@ -23,7 +23,7 @@ var getObjRef = function (node, nodes, file, scope) {
       return ref;
     }
   } else {
-    throw new Error("We can't explode this node type " + node.type);
+    throw new Error(`We can't explode this node type ${node.type}`);
   }
 
   var temp = scope.generateUidBasedOnNode(ref);

src/babel/transformation/helpers/name-method.js

@@ -89,7 +89,7 @@ var visit = function (node, name, scope) {
   return state;
 };
 
-exports.property = function (node, file, scope) {
+export function property(node, file, scope) {
   var key = t.toComputedKey(node, node.key);
   if (!t.isLiteral(key)) return node; // we can't set a function id with this
 
@@ -99,9 +99,9 @@ exports.property = function (node, file, scope) {
   var method = node.value;
   var state  = visit(method, name, scope);
   node.value = wrap(state, method, id, scope);
-};
+}
 
-exports.bare = function (node, parent, scope) {
+export function bare(node, parent, scope) {
   // has an `id` so we don't need to infer one
   if (node.id) return;
 
@@ -123,4 +123,4 @@ exports.bare = function (node, parent, scope) {
 
   var state = visit(node, name, scope);
   return wrap(state, node, id, scope);
-};
+}

src/babel/transformation/helpers/react.js

@@ -2,7 +2,7 @@ import t from "../../types";
 
 var isCreateClassCallExpression = t.buildMatchMemberExpression("React.createClass");
 
-exports.isCreateClass = function (node) {
+export function isCreateClass(node) {
   if (!node || !t.isCallExpression(node)) return false;
 
   // not React.createClass call member object
@@ -17,10 +17,10 @@ exports.isCreateClass = function (node) {
   if (!t.isObjectExpression(first)) return false;
 
   return true;
-};
+}
 
-exports.isReactComponent = t.buildMatchMemberExpression("React.Component");
+export var isReactComponent = t.buildMatchMemberExpression("React.Component");
 
-exports.isCompatTag = function (tagName) {
+export function isCompatTag(tagName) {
   return tagName && /^[a-z]|\-/.test(tagName);
-};
+}

src/babel/transformation/helpers/strict.js

@@ -1,13 +1,13 @@
 import t from "../../types";
 
-exports.has = function (node) {
+export function has(node) {
   var first = node.body[0];
   return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
-};
+}
 
-exports.wrap = function (node, callback) {
+export function wrap(node, callback) {
   var useStrictNode;
-  if (exports.has(node)) {
+  if (has(node)) {
     useStrictNode = node.body.shift();
   }
 
@@ -16,4 +16,4 @@ exports.wrap = function (node, callback) {
   if (useStrictNode) {
     node.body.unshift(useStrictNode);
   }
-};
+}

src/babel/transformation/index.js

@@ -25,9 +25,12 @@ transform._ensureTransformerNames = function (type, rawKeys) {
     var key = rawKeys[i];
 
     var deprecatedKey = transform.deprecatedTransformerMap[key];
-    if (deprecatedKey) {
+    var aliasKey = transform.aliasTransformerMap[key];
+    if (aliasKey) {
+      keys.push(aliasKey);
+    } else if (deprecatedKey) {
       // deprecated key, remap it to the new one
-      console.error("The transformer " + key + " has been renamed to " + deprecatedKey);
+      console.error(`The transformer ${key} has been renamed to ${deprecatedKey}`);
       rawKeys.push(deprecatedKey);
     } else if (transform.transformers[key]) {
       // valid key
@@ -37,7 +40,7 @@ transform._ensureTransformerNames = function (type, rawKeys) {
       keys = keys.concat(transform.namespaces[key]);
     } else {
       // invalid key
-      throw new ReferenceError("Unknown transformer " + key + " specified in " + type);
+      throw new ReferenceError(`Unknown transformer ${key} specified in ${type}`);
     }
   }
 
@@ -49,6 +52,7 @@ transform.transformers          = object();
 transform.namespaces            = object();
 
 transform.deprecatedTransformerMap = require("./transformers/deprecated");
+transform.aliasTransformerMap = require("./transformers/aliases");
 transform.moduleFormatters = require("./modules");
 
 import rawTransformers from "./transformers";

src/babel/transformation/transformer-pass.js

@@ -56,7 +56,7 @@ export default class TransformerPass {
 
     var file = this.file;
 
-    file.debug("Running transformer " + this.transformer.key);
+    file.debug(`Running transformer ${this.transformer.key}`);
 
     file.scope.traverse(file.ast, this.handlers, file);
   }

src/babel/transformation/transformers/aliases.json

@@ -0,0 +1,3 @@
+{
+  "useStrict": "strict"
+}

src/babel/transformation/transformers/deprecated.json

@@ -1,4 +1,8 @@
 {
   "selfContained": "runtime",
-  "unicode-regex": "regex.unicode"
+  "unicode-regex": "regex.unicode",
+
+  "minification.deadCodeElimination": "utility.deadCodeElimination",
+  "minification.removeConsoleCalls": "utility.removeConsole",
+  "minification.removeDebugger": "utility.removeDebugger"
 }

src/babel/transformation/transformers/es5/properties.mutators.js

@@ -1,4 +1,4 @@
-import defineMap from "../../helpers/define-map";
+import * as defineMap from "../../helpers/define-map";
 import t from "../../../types";
 
 export function check(node) {

src/babel/transformation/transformers/es6/arrow-functions.js

@@ -1,6 +1,6 @@
 import t from "../../../types";
 
-exports.check = t.isArrowFunctionExpression;
+export var check = t.isArrowFunctionExpression;
 
 export function ArrowFunctionExpression(node) {
   t.ensureBlock(node);

src/babel/transformation/transformers/es6/block-scoping-tdz.js

@@ -26,18 +26,16 @@ var visitor = {
   }
 };
 
-exports.optional = true;
+export var optional = true;
 
-exports.Loop =
-exports.Program =
-exports.BlockStatement = function (node, parent, scope, file) {
+export function BlockStatement(node, parent, scope, file) {
   var letRefs = node._letReferences;
   if (!letRefs) return;
 
-  var state = {
+  scope.traverse(node, visitor, {
     letRefs: letRefs,
     file:    file
-  };
+  });
+}
 
-  scope.traverse(node, visitor, state);
-};
+export { BlockStatement as Program, BlockStatement as Loop };

src/babel/transformation/transformers/es6/block-scoping.js

@@ -5,11 +5,7 @@ import t from "../../../types";
 import values from "lodash/object/values";
 import extend from "lodash/object/extend";
 
-exports.check = function (node) {
-  return t.isVariableDeclaration(node) && (node.kind === "let" || node.kind === "const");
-};
-
-var isLet = function (node, parent) {
+function isLet(node, parent) {
   if (!t.isVariableDeclaration(node)) return false;
   if (node._let) return true;
   if (node.kind !== "let") return false;
@@ -25,23 +21,27 @@ var isLet = function (node, parent) {
   node._let = true;
   node.kind = "var";
   return true;
-};
+}
 
-var isLetInitable = function (node, parent) {
+function isLetInitable(node, parent) {
   return !t.isFor(parent) || !t.isFor(parent, { left: node });
-};
+}
 
-var isVar = function (node, parent) {
+function isVar(node, parent) {
   return t.isVariableDeclaration(node, { kind: "var" }) && !isLet(node, parent);
-};
+}
 
-var standardizeLets = function (declars) {
+function standardizeLets(declars) {
   for (var i = 0; i < declars.length; i++) {
     delete declars[i]._let;
   }
-};
+}
 
-exports.VariableDeclaration = function (node, parent, scope, file) {
+export function check(node) {
+  return t.isVariableDeclaration(node) && (node.kind === "let" || node.kind === "const");
+}
+
+export function VariableDeclaration(node, parent, scope, file) {
   if (!isLet(node, parent)) return;
 
   if (isLetInitable(node) && file.transformers["es6.blockScopingTDZ"].canRun()) {
@@ -61,9 +61,9 @@ exports.VariableDeclaration = function (node, parent, scope, file) {
 
     return nodes;
   }
-};
+}
 
-exports.Loop = function (node, parent, scope, file) {
+export function Loop(node, parent, scope, file) {
   var init = node.left || node.init;
   if (isLet(init, node)) {
     t.ensureBlock(node);
@@ -71,15 +71,16 @@ exports.Loop = function (node, parent, scope, file) {
   }
   var blockScoping = new BlockScoping(node, node.body, parent, scope, file);
   blockScoping.run();
-};
+}
 
-exports.Program =
-exports.BlockStatement = function (block, parent, scope, file) {
+export function BlockStatement(block, parent, scope, file) {
   if (!t.isLoop(parent)) {
     var blockScoping = new BlockScoping(false, block, parent, scope, file);
     blockScoping.run();
   }
-};
+}
+
+export { BlockStatement as Program };
 
 function replace(node, parent, scope, remaps) {
   if (!t.isReferencedIdentifier(node, parent)) return;
@@ -188,7 +189,7 @@ var loopVisitor = {
           return;
         }
 
-        loopText = loopText + "|" + node.label.name;
+        loopText = `${loopText}|${node.label.name}`;
       } else {
         // we shouldn't be transforming these statements because
         // they don't refer to the actual loop we're scopifying
@@ -326,7 +327,7 @@ class BlockScoping {
       for (var name in outsideRefs) {
         var id = outsideRefs[name];
 
-        if (this.scope.hasGlobal(id.name)) {
+        if (this.scope.hasGlobal(id.name) || this.scope.parentHasBinding(id.name)) {
           delete outsideRefs[id.name];
           delete this.letReferences[id.name];
 

src/babel/transformation/transformers/es6/classes.js

@@ -1,17 +1,17 @@
 import ReplaceSupers from "../../helpers/replace-supers";
-import nameMethod from "../../helpers/name-method";
-import defineMap from "../../helpers/define-map";
+import * as nameMethod from "../../helpers/name-method";
+import * as defineMap from "../../helpers/define-map";
 import * as messages from "../../../messages";
 import * as util from  "../../../util";
 import t from "../../../types";
 
-exports.check = t.isClass;
+export var check = t.isClass;
 
-exports.ClassDeclaration = function (node, parent, scope, file) {
+export function ClassDeclaration(node, parent, scope, file) {
   return new ClassTransformer(node, file, scope, true).run();
-};
+}
 
-exports.ClassExpression = function (node, parent, scope, file) {
+export function ClassExpression(node, parent, scope, file) {
   if (!node.id) {
     if (t.isProperty(parent) && parent.value === node && !parent.computed && t.isIdentifier(parent.key)) {
       // var o = { foo: class {} };
@@ -25,7 +25,7 @@ exports.ClassExpression = function (node, parent, scope, file) {
   }
 
   return new ClassTransformer(node, file, scope, false).run();
-};
+}
 
 class ClassTransformer {
 
@@ -182,7 +182,7 @@ class ClassTransformer {
     }
 
     // we have no constructor, we have a super, and the super doesn't appear to be falsy
-    if (!this.hasConstructor && this.hasSuper && !t.isFalsyExpression(superName)) {
+    if (!this.hasConstructor && this.hasSuper && t.evaluateTruthy(superName, this.scope) !== false) {
       var helperName = "class-super-constructor-call";
       if (this.isLoose) helperName += "-loose";
       constructor.body.body.push(util.template(helperName, {

src/babel/transformation/transformers/es6/constants.js

@@ -1,9 +1,9 @@
 import * as messages from "../../../messages";
 import t from "../../../types";
 
-exports.check = function (node) {
+export function check(node) {
   return t.isVariableDeclaration(node, { kind: "const" });
-};
+}
 
 var visitor = {
   enter(node, parent, scope, state) {
@@ -36,13 +36,13 @@ var visitor = {
   }
 };
 
-exports.Scopable = function (node, parent, scope, file) {
+export function Scopable(node, parent, scope, file) {
   scope.traverse(node, visitor, {
     constants: scope.getAllBindingsOfKind("const"),
     file:      file
   });
-};
+}
 
-exports.VariableDeclaration = function (node) {
+export function VariableDeclaration(node) {
   if (node.kind === "const") node.kind = "let";
-};
+}

src/babel/transformation/transformers/es6/destructuring.js

@@ -1,10 +1,9 @@
 import * as messages from "../../../messages";
 import t from "../../../types";
 
-exports.check = t.isPattern;
+export var check = t.isPattern;
 
-exports.ForInStatement =
-exports.ForOfStatement = function (node, parent, scope, file) {
+export function ForOfStatement(node, parent, scope, file) {
   var left = node.left;
 
   if (t.isPattern(left)) {
@@ -50,17 +49,19 @@ exports.ForOfStatement = function (node, parent, scope, file) {
 
   var block = node.body;
   block.body = nodes.concat(block.body);
-};
+}
+
+export { ForOfStatement as ForInStatement };
 
 exports.Function = function (node, parent, scope, file) {
   var nodes = [];
 
-  var hasDestructuringTransformer = false;
+  var hasDestructuring = false;
 
   node.params = node.params.map(function (pattern, i) {
     if (!t.isPattern(pattern)) return pattern;
 
-    hasDestructuringTransformer = true;
+    hasDestructuring = true;
     var ref = scope.generateUidIdentifier("ref");
 
     var destructuring = new DestructuringTransformer({
@@ -68,22 +69,23 @@ exports.Function = function (node, parent, scope, file) {
       nodes:      nodes,
       scope:      scope,
       file:       file,
-      kind:       "var",
+      kind:       "let"
     });
     destructuring.init(pattern, ref);
 
     return ref;
   });
 
-  if (!hasDestructuringTransformer) return;
+  if (!hasDestructuring) return;
 
+  file.checkNode(nodes);
   t.ensureBlock(node);
 
   var block = node.body;
   block.body = nodes.concat(block.body);
 };
 
-exports.CatchClause = function (node, parent, scope, file) {
+export function CatchClause(node, parent, scope, file) {
   var pattern = node.param;
   if (!t.isPattern(pattern)) return;
 
@@ -103,9 +105,9 @@ exports.CatchClause = function (node, parent, scope, file) {
   node.body.body = nodes.concat(node.body.body);
 
   return node;
-};
+}
 
-exports.ExpressionStatement = function (node, parent, scope, file) {
+export function ExpressionStatement(node, parent, scope, file) {
   var expr = node.expression;
   if (expr.type !== "AssignmentExpression") return;
   if (!t.isPattern(expr.left)) return;
@@ -127,9 +129,9 @@ exports.ExpressionStatement = function (node, parent, scope, file) {
   destructuring.init(expr.left, ref);
 
   return nodes;
-};
+}
 
-exports.AssignmentExpression = function (node, parent, scope, file) {
+export function AssignmentExpression(node, parent, scope, file) {
   if (!t.isPattern(node.left)) return;
 
   var ref = scope.generateUidIdentifier("temp");
@@ -152,18 +154,18 @@ exports.AssignmentExpression = function (node, parent, scope, file) {
   nodes.push(ref);
 
   return t.toSequenceExpression(nodes, scope);
-};
+}
 
-var variableDeclarationHasPattern = function (node) {
+function variableDeclarationHasPattern(node) {
   for (var i = 0; i < node.declarations.length; i++) {
     if (t.isPattern(node.declarations[i].id)) {
       return true;
     }
   }
   return false;
-};
+}
 
-exports.VariableDeclaration = function (node, parent, scope, file) {
+export function VariableDeclaration(node, parent, scope, file) {
   if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
   if (!variableDeclarationHasPattern(node)) return;
 

src/babel/transformation/transformers/es6/for-of.js

@@ -2,9 +2,9 @@ import * as messages from "../../../messages";
 import * as util from  "../../../util";
 import t from "../../../types";
 
-exports.check = t.isForOfStatement;
+export var check = t.isForOfStatement;
 
-exports.ForOfStatement = function (node, parent, scope, file) {
+export function ForOfStatement(node, parent, scope, file) {
   var callback = spec;
   if (file.isLoose("es6.forOf")) callback = loose;
 
@@ -32,8 +32,12 @@ exports.ForOfStatement = function (node, parent, scope, file) {
   // todo: find out why this is necessary? #538
   loop._scopeInfo = node._scopeInfo;
 
-  return build.node;
-};
+  if (build.replaceParent) {
+    this.parentPath.node = build.node;
+  } else {
+    return build.node;
+  }
+}
 
 var breakVisitor = {
   enter(node, parent, scope, state) {
@@ -97,7 +101,9 @@ var loose = function (node, parent, scope, file) {
 
   scope.traverse(node, breakVisitor, {
     iteratorKey: iteratorKey,
-    wrapReturn:  function (node) {
+    label:       t.isLabeledStatement(parent) && parent.label.name,
+
+    wrapReturn(node) {
       return t.ifStatement(
         t.logicalExpression(
           "&&",
@@ -105,8 +111,7 @@ var loose = function (node, parent, scope, file) {
           t.memberExpression(iteratorKey, t.identifier("return")
         )
       ), node);
-    },
-    label:       t.isLabeledStatement(parent) && parent.label.name
+    }
   });
 
   //
@@ -151,14 +156,22 @@ var spec = function (node, parent, scope, file) {
     BODY:                   null
   });
 
-  var loop = template[3].block.body[0];
+  var isLabeledParent = t.isLabeledStatement(parent);
+
+  var tryBody = template[3].block.body;
+  var loop = tryBody[0];
+
+  if (isLabeledParent) {
+    tryBody[0] = t.labeledStatement(parent.label, loop);
+  }
 
   //
 
   scope.traverse(node, breakVisitor, {
     iteratorKey: iteratorKey,
-    label:       t.isLabeledStatement(parent) && parent.label.name,
-    wrapReturn:  function (node) {
+    label:       isLabeledParent && parent.label.name,
+
+    wrapReturn(node) {
       return t.ifStatement(t.memberExpression(iteratorKey, t.identifier("return")), node);
     }
   });
@@ -166,8 +179,9 @@ var spec = function (node, parent, scope, file) {
   //
 
   return {
-    declar: declar,
-    loop:   loop,
-    node:   template
+    replaceParent: isLabeledParent,
+    declar:        declar,
+    loop:          loop,
+    node:          template
   };
 };

src/babel/transformation/transformers/es6/parameters.default.js

@@ -61,7 +61,7 @@ exports.Function = function (node, parent, scope, file) {
         scope.traverse(param, iifeVisitor, state);
       }
 
-      if (file.transformers["es6.blockScopingTDZ"].canRun()) {
+      if (file.transformers["es6.blockScopingTDZ"].canRun() && t.isIdentifier(param)) {
         pushDefNode(param, t.identifier("undefined"), i);
       }
 

src/babel/transformation/transformers/es6/parameters.rest.js

@@ -2,7 +2,7 @@ import isNumber from "lodash/lang/isNumber";
 import * as util from  "../../../util";
 import t from "../../../types";
 
-exports.check = t.isRestElement;
+export var check = t.isRestElement;
 
 var memberExpressionOptimisationVisitor = {
   enter(node, parent, scope, state) {
@@ -28,26 +28,24 @@ var memberExpressionOptimisationVisitor = {
       // optimise it
       var prop = parent.property;
       if (isNumber(prop.value) || t.isUnaryExpression(prop) || t.isBinaryExpression(prop)) {
-        optimizeMemberExpression(node, parent, state.method.params.length);
-        state.hasShorthand = true;
+        state.candidates.push(this);
         return;
       }
     }
 
-    state.longForm = true;
+    state.canOptimise = false;
+    this.stop();
   }
 };
 
-function optimizeMemberExpression(node, parent, offset) {
+function optimizeMemberExpression(parent, offset) {
   var newExpr;
   var prop = parent.property;
 
   if (t.isLiteral(prop)) {
-    node.name = "arguments";
     prop.value += offset;
     prop.raw = String(prop.value);
   } else { // // UnaryExpression, BinaryExpression
-    node.name = "arguments";
     newExpr = t.binaryExpression("+", prop, t.literal(offset));
     parent.property = newExpr;
   }
@@ -57,7 +55,7 @@ var hasRest = function (node) {
   return t.isRestElement(node.params[node.params.length - 1]);
 };
 
-exports.Function = function (node, parent, scope) {
+exports.Function = function (node, parent, scope, file) {
   if (!hasRest(node)) return;
 
   var rest = node.params.pop().argument;
@@ -71,10 +69,12 @@ exports.Function = function (node, parent, scope) {
   if (t.isPattern(rest)) {
     var pattern = rest;
     rest = scope.generateUidIdentifier("ref");
-    var declar = t.variableDeclaration("var", pattern.elements.map(function (elem, index) {
+
+    var declar = t.variableDeclaration("let", pattern.elements.map(function (elem, index) {
       var accessExpr = t.memberExpression(rest, t.literal(index), true);
       return t.variableDeclarator(elem, accessExpr);
     }));
+    file.checkNode(declar);
     node.body.body.unshift(declar);
   }
 
@@ -82,16 +82,23 @@ exports.Function = function (node, parent, scope) {
 
   var state = {
     outerBinding: scope.getBindingIdentifier(rest.name),
-    hasShorthand: true,
-    longForm:     false,
+    canOptimise:  true,
+    candidates:   [],
     method:       node,
-    name:         rest.name,
+    name:         rest.name
   };
 
   scope.traverse(node, memberExpressionOptimisationVisitor, state);
 
   // we only have shorthands and there's no other references
-  if (!state.longForm && state.hasShorthand) return;
+  if (state.canOptimise && state.candidates.length) {
+    for (var i = 0; i < state.candidates.length; i++) {
+      var candidate = state.candidates[i];
+      candidate.node = argsId;
+      optimizeMemberExpression(candidate.parent, node.params.length);
+    }
+    return;
+  }
 
   //
 

src/babel/transformation/transformers/es6/spread.js

@@ -1,8 +1,6 @@
 import includes from "lodash/collection/includes";
 import t from "../../../types";
 
-exports.check = t.isSpreadElement;
-
 function getSpreadLiteral(spread, scope) {
   return scope.toArray(spread.argument, true);
 }
@@ -42,6 +40,8 @@ function build(props, scope) {
   return nodes;
 }
 
+export var check = t.isSpreadElement;
+
 export function ArrayExpression(node, parent, scope) {
   var elements = node.elements;
   if (!hasSpread(elements)) return;

src/babel/transformation/transformers/es6/tail-call.js

@@ -229,7 +229,7 @@ class TailCallTransformer {
   subTransform(node) {
     if (!node) return;
 
-    var handler = this["subTransform" + node.type];
+    var handler = this[`subTransform${node.type}`];
     if (handler) return handler.call(this, node);
   }
 

src/babel/transformation/transformers/index.js

@@ -1,5 +1,5 @@
 export default {
-  useStrict:                               require("./other/use-strict"),
+  strict:                                  require("./other/strict"),
 
   "validation.undeclaredVariableCheck":    require("./validation/undeclared-variable-check"),
   "validation.noForInOfAssignment":        require("./validation/no-for-in-of-assignment"),
@@ -97,16 +97,18 @@ export default {
   "spec.typeofSymbol":                     require("./spec/typeof-symbol"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
 
-  _useStrict:                              require("./internal/use-strict"),
+  _strict:                                 require("./internal/strict"),
   _moduleFormatter:                        require("./internal/module-formatter"),
 
   "es3.propertyLiterals":                  require("./es3/property-literals"),
   "es3.memberExpressionLiterals":          require("./es3/member-expression-literals"),
 
-  "minification.removeDebugger":           require("./minification/remove-debugger"),
-  "minification.removeConsoleCalls":       require("./minification/remove-console-calls"),
-  "minification.deadCodeElimination":      require("./minification/dead-code-elimination"),
-  "minification.renameLocalVariables":     require("./minification/rename-local-variables"),
+  "utility.removeDebugger":                require("./utility/remove-debugger"),
+  "utility.removeConsole":                 require("./utility/remove-console"),
+
+  "utility.inlineEnvironmentVariables":    require("./utility/inline-environment-variables"),
+  "utility.inlineExpressions":             require("./utility/inline-expressions"),
+  "utility.deadCodeElimination":           require("./utility/dead-code-elimination"),
 
   _cleanUp:                                require("./internal/cleanup")
 };

src/babel/transformation/transformers/internal/alias-functions.js

@@ -76,16 +76,17 @@ var go = function (getBody, node, scope) {
   }
 };
 
-exports.Program = function (node, parent, scope) {
+export function Program(node, parent, scope) {
   go(function () {
     return node.body;
   }, node, scope);
 };
 
-exports.FunctionDeclaration =
-exports.FunctionExpression = function (node, parent, scope) {
+export function FunctionDeclaration(node, parent, scope) {
   go(function () {
     t.ensureBlock(node);
     return node.body.body;
   }, node, scope);
-};
+}
+
+export { FunctionDeclaration as FunctionExpression };

src/babel/transformation/transformers/internal/block-hoist.js

@@ -9,8 +9,7 @@ import values from "lodash/object/values";
 //  - 2 Priority over normal nodes
 //  - 3 We want this to be at the **very** top
 
-exports.BlockStatement =
-exports.Program = {
+export var BlockStatement = {
   exit(node) {
     var hasChange = false;
     for (var i = 0; i < node.body.length; i++) {
@@ -29,3 +28,5 @@ exports.Program = {
     node.body = flatten(values(nodePriorities).reverse());
   }
 };
+
+export { BlockStatement as Program };

src/babel/transformation/transformers/internal/cleanup.js

@@ -1,5 +1,15 @@
-export function SequenceExpression(node) {
-  if (node.expressions.length === 1) {
-    return node.expressions[0];
+export var SequenceExpression = {
+  exit(node) {
+    if (node.expressions.length === 1) {
+      return node.expressions[0];
+    } else if (!node.expressions.length) {
+      this.remove();
+    }
   }
-}
+};
+
+export var ExpressionStatement = {
+  exit(node) {
+    if (!node.expression) this.remove();
+  }
+};

src/babel/transformation/transformers/internal/declarations.js

@@ -1,13 +1,12 @@
-import useStrict from "../../helpers/use-strict";
+import * as strict from "../../helpers/strict";
 import t from "../../../types";
 
 export var secondPass = true;
 
-exports.BlockStatement =
-exports.Program = function (node, parent, scope, file) {
+export function BlockStatement(node, parent, scope, file) {
   if (!node._declarations) return;
 
-  useStrict.wrap(node, function () {
+  strict.wrap(node, function () {
     var kinds = {};
     var kind;
 
@@ -31,4 +30,6 @@ exports.Program = function (node, parent, scope, file) {
 
     node._declarations = null;
   });
-};
+}
+
+export { BlockStatement as Program };

src/babel/transformation/transformers/internal/module-formatter.js

@@ -1,9 +1,9 @@
-import useStrict from "../../helpers/use-strict";
+import * as strict from "../../helpers/strict";
 
 export function Program(program, parent, scope, file) {
   if (!file.transformers["es6.modules"].canRun()) return;
 
-  useStrict.wrap(program, function () {
+  strict.wrap(program, function () {
     program.body = file.dynamicImports.concat(program.body);
   });
 

src/babel/transformation/transformers/internal/strict.js

@@ -1,7 +1,7 @@
 import t from "../../../types";
 
 export function Program(program, parent, scope, file) {
-  if (file.transformers.useStrict.canRun()) {
+  if (file.transformers.strict.canRun()) {
     program.body.unshift(t.expressionStatement(t.literal("use strict")));
   }
 }

src/babel/transformation/transformers/minification/rename-local-variables.js

@@ -1,9 +0,0 @@
-//import t from "../../../types";
-
-export var optional = true;
-
-export function Scopable() {
-  //for (var name in scope.bindings) {
-  //  scope.rename(name, scope.generateUidIdentifier("a").name);
-  //}
-}

src/babel/transformation/transformers/other/flow.js

@@ -1,5 +1,25 @@
 import t from "../../../types";
 
+export function Flow(node) {
+  this.remove();
+}
+
+export function ClassProperty(node) {
+  node.typeAnnotation = null;
+  if (!node.value) this.remove();
+}
+
+export function Class(node) {
+  node.implements = null;
+}
+
+exports.Function = function (node) {
+  for (var i = 0; i < node.params.length; i++) {
+    var param = node.params[i];
+    param.optional = false;
+  }
+};
+
 export function TypeCastExpression(node) {
   return node.expression;
 }

src/babel/transformation/transformers/other/react-compat.js

@@ -1,4 +1,4 @@
-import react from "../../helpers/react";
+import * as react from "../../helpers/react";
 import t from "../../../types";
 
 export function manipulateOptions(opts) {

src/babel/transformation/transformers/other/react.js

@@ -1,4 +1,4 @@
-import react from "../../helpers/react";
+import * as react from "../../helpers/react";
 import t from "../../../types";
 
 var JSX_ANNOTATION_REGEX = /^\*\s*@jsx\s+([^\s]+)/;

src/babel/transformation/transformers/other/strict.js

@@ -8,10 +8,11 @@ export function Program(program) {
   }
 }
 
-exports.FunctionDeclaration =
-exports.FunctionExpression = function () {
+export function FunctionExpression() {
   this.skip();
-};
+}
+
+export { FunctionExpression as FunctionDeclaration };
 
 export function ThisExpression() {
   return t.identifier("undefined");

src/babel/transformation/transformers/playground/object-getter-memoization.js

@@ -16,8 +16,7 @@ var visitor = {
   }
 };
 
-exports.Property =
-exports.MethodDefinition = function (node, parent, scope, file) {
+export function MethodDefinition(node, parent, scope, file) {
   if (node.kind !== "memo") return;
   node.kind = "get";
 
@@ -38,4 +37,6 @@ exports.MethodDefinition = function (node, parent, scope, file) {
   scope.traverse(value, visitor, state);
 
   return node;
-};
+}
+
+export { MethodDefinition as Property };

src/babel/transformation/transformers/utility/dead-code-elimination.js

@@ -1,31 +1,41 @@
 import t from "../../../types";
 
+function toStatements(node) {
+  if (t.isBlockStatement(node)) {
+    var hasBlockScoped = false;
+
+    for (var i = 0; i < node.body.length; i++) {
+      var bodyNode = node.body[i];
+      if (t.isBlockScoped(bodyNode)) hasBlockScoped = true;
+    }
+
+    if (!hasBlockScoped) {
+      return node.body;
+    }
+  }
+
+  return node;
+}
+
 export var optional = true;
 
-export function ExpressionStatement(node) {
-  // remove consequence-less expressions such as local variables and literals
-  // note: will remove directives
-  //
-  //   var foo = true; foo; -> var foo = true;
-  //   "foo"; ->
-  //
-
-  var expr = node.expression;
-  if (t.isLiteral(expr) || (t.isIdentifier(node) && t.hasBinding(node.name))) {
-    this.remove();
+export function ConditionalExpression(node, parent, scope) {
+  var evaluateTest = t.evaluateTruthy(node.test, scope);
+  if (evaluateTest === true) {
+    return node.consequent;
+  } else if (evaluateTest === false) {
+    return node.alternate;
   }
 }
 
 export var IfStatement = {
-  exit(node) {
-    // todo: in scenarios where we can just return the consequent or
-    // alternate we should drop the block statement if it contains no
-    // block scoped variables
-
+  exit(node, parent, scope) {
     var consequent = node.consequent;
     var alternate  = node.alternate;
     var test       = node.test;
 
+    var evaluateTest = t.evaluateTruthy(test, scope);
+
     // we can check if a test will be truthy 100% and if so then we can inline
     // the consequent and completely ignore the alternate
     //
@@ -33,8 +43,8 @@ export var IfStatement = {
     //   if ("foo") { foo; } -> { foo; }
     //
 
-    if (t.isLiteral(test) && test.value) {
-      return consequent;
+    if (evaluateTest === true) {
+      return toStatements(consequent);
     }
 
     // we can check if a test will be falsy 100% and if so we can inline the
@@ -44,9 +54,9 @@ export var IfStatement = {
     //   if ("") { bar; } ->
     //
 
-    if (t.isFalsyExpression(test)) {
+    if (evaluateTest === false) {
       if (alternate) {
-        return alternate;
+        return toStatements(alternate);
       } else {
         return this.remove();
       }
@@ -67,7 +77,7 @@ export var IfStatement = {
     //   if (foo) {} else { bar; } -> if (!foo) { bar; }
     //
 
-    if (t.blockStatement(consequent) && !consequent.body.length && t.isBlockStatement(alternate) && alternate.body.length) {
+    if (t.isBlockStatement(consequent) && !consequent.body.length && t.isBlockStatement(alternate) && alternate.body.length) {
       node.consequent = node.alternate;
       node.alternate  = null;
       node.test       = t.unaryExpression("!", test, true);

src/babel/transformation/transformers/utility/inline-environment-variables.js

@@ -0,0 +1,14 @@
+import t from "../../../types";
+
+export var optional = true;
+
+var match = t.buildMatchMemberExpression("process.env");
+
+export function MemberExpression(node) {
+  if (match(node.object)) {
+    var key = t.toComputedKey(node, node.property);
+    if (t.isLiteral(key)) {
+      return t.valueToNode(process.env[key.value]);
+    }
+  }
+}

src/babel/transformation/transformers/utility/inline-expressions.js

@@ -0,0 +1,12 @@
+import t from "../../../types";
+
+export var optional = true;
+
+export function Expression(node, parent, scope) {
+  var res = t.evaluate(node, scope);
+  if (res.confident) return t.valueToNode(res.value);
+}
+
+export function Identifier() {
+  // override Expression
+}

src/babel/transformation/transformers/validation/no-for-in-of-assignment.js

@@ -3,11 +3,12 @@ import t from "../../../types";
 
 export { isFor as check } from "../../../types";
 
-exports.ForInStatement =
-exports.ForOfStatement = function (node, parent, scope, file) {
+export function ForOfStatement(node, parent, scope, file) {
   var left = node.left;
   if (t.isVariableDeclaration(left)) {
     var declar = left.declarations[0];
     if (declar.init) throw file.errorWithNode(declar, messages.get("noAssignmentsInForHead"));
   }
-};
+}
+
+export { ForOfStatement as ForInStatement };

src/babel/transformation/transformers/validation/setters.js

@@ -4,9 +4,10 @@ export function check(node) {
   return node.kind === "set";
 }
 
-exports.MethodDefinition =
-exports.Property = function (node, parent, scope, file) {
+export function Property(node, parent, scope, file) {
   if (node.kind === "set" && node.value.params.length !== 1) {
     throw file.errorWithNode(node.value, messages.get("settersInvalidParamLength"));
   }
-};
+}
+
+export { Property as MethodDefinition };

src/babel/traversal/context.js

@@ -43,7 +43,7 @@ export default class TraversalConext {
     if (this.shouldFlatten) {
       node[key] = flatten(node[key]);
 
-      if (key === "body") {
+      if (key === "body" || key === "expressions") {
         // we can safely compact this
         node[key] = compact(node[key]);
       }

src/babel/traversal/index.js

@@ -9,7 +9,7 @@ function traverse(parent, opts, scope, state) {
 
   if (!opts.noScope && !scope) {
     if (parent.type !== "Program" && parent.type !== "File") {
-      throw new Error("Must pass a scope unless traversing a Program/File got a " + parent.type + " node");
+      throw new Error(`Must pass a scope unless traversing a Program/File got a ${parent.type} node`);
     }
   }
 
@@ -84,7 +84,7 @@ traverse.explode = function (obj) {
     var aliases = t.FLIPPED_ALIAS_KEYS[type];
     if (aliases) {
       for (var i = 0; i < aliases.length; i++) {
-        obj[aliases[i]] = fns;
+        obj[aliases[i]] ||= fns;
       }
     }
   }

src/babel/traversal/scope.js

@@ -143,7 +143,7 @@ export default class Scope {
   _generateUid(name, i) {
     var id = name;
     if (i > 1) id += i;
-    return "_" + id;
+    return `_${id}`;
   }
 
   /*
@@ -299,7 +299,7 @@ export default class Scope {
     var info = this.getBindingInfo(name);
     if (!info) return;
 
-    info.identifier.typeAnnotation = info.typeAnnotation = type;
+    info.typeAnnotation = type;
   }
 
   getTypeAnnotation(name, id, node) {
@@ -415,7 +415,7 @@ export default class Scope {
   registerVariableDeclaration(declar) {
     var declars = declar.declarations;
     for (var i = 0; i < declars.length; i++) {
-      this.registerBinding(declars[i], declar.kind);
+      this.registerBinding(declar.kind, declars[i]);
     }
   }
 
@@ -538,7 +538,7 @@ export default class Scope {
         init: opts.init
       };
     } else {
-      throw new TypeError("cannot add a declaration here in node type " + block.type);
+      throw new TypeError(`cannot add a declaration here in node type ${block.type}`);
     }
   }
 
@@ -626,6 +626,37 @@ export default class Scope {
     return binding && binding.identifier;
   }
 
+
+  getOwnImmutableBindingValue(name) {
+    return this._immutableBindingInfoToValue(this.getOwnBindingInfo(name));
+  }
+
+  getImmutableBindingValue(name) {
+    return this._immutableBindingInfoToValue(this.getBindingInfo(name));
+  }
+
+  _immutableBindingInfoToValue(info) {
+    if (!info) return;
+
+    // can't guarantee this value is the same
+    if (info.reassigned) return;
+
+    var node = info.node;
+    if (t.isVariableDeclarator(node)) {
+      if (t.isIdentifier(node.id)) {
+        node = node.init;
+      } else {
+        // otherwise it's probably a destructuring like:
+        // var { foo } = "foo";
+        return;
+      }
+    }
+
+    if (t.isImmutable(node)) {
+      return node;
+    }
+  }
+
   // has
 
   hasOwnBinding(name) {

src/babel/types/alias-keys.json

@@ -71,6 +71,39 @@
   "JSXMemberExpression":       ["Expression"],
   "YieldExpression":           ["Expression"],
 
+  "AnyTypeAnnotation":           ["Flow"],
+  "ArrayTypeAnnotation":         ["Flow"],
+  "BooleanTypeAnnotation":       ["Flow"],
+  "ClassImplements":             ["Flow"],
+  "DeclareClass":                ["Flow"],
+  "DeclareFunction":             ["Flow"],
+  "DeclareModule":               ["Flow"],
+  "DeclareVariable":             ["Flow"],
+  "FunctionTypeAnnotation":      ["Flow"],
+  "FunctionTypeParam":           ["Flow"],
+  "GenericTypeAnnotation":       ["Flow"],
+  "InterfaceExtends":            ["Flow"],
+  "InterfaceDeclaration":        ["Flow"],
+  "IntersectionTypeAnnotation":  ["Flow"],
+  "NullableTypeAnnotation":      ["Flow"],
+  "NumberTypeAnnotation":        ["Flow"],
+  "StringLiteralTypeAnnotation": ["Flow"],
+  "StringTypeAnnotation":        ["Flow"],
+  "TupleTypeAnnotation":         ["Flow"],
+  "TypeofTypeAnnotation":        ["Flow"],
+  "TypeAlias":                   ["Flow"],
+  "TypeAnnotation":              ["Flow"],
+  "TypeCastExpression":          ["Flow"],
+  "TypeParameterDeclaration":    ["Flow"],
+  "TypeParameterInstantiation":  ["Flow"],
+  "ObjectTypeAnnotation":        ["Flow"],
+  "ObjectTypeCallProperty":      ["Flow"],
+  "ObjectTypeIndexer":           ["Flow"],
+  "ObjectTypeProperty":          ["Flow"],
+  "QualifiedTypeIdentifier":     ["Flow"],
+  "UnionTypeAnnotation":         ["Flow"],
+  "VoidTypeAnnotation":          ["Flow"],
+
   "JSXAttribute":           ["JSX"],
   "JSXClosingElement":      ["JSX"],
   "JSXElement":             ["JSX", "Expression"],

src/babel/types/builder-keys.json

@@ -84,6 +84,11 @@
     "name": null
   },
 
+  "LabeledStatement": {
+    "label": null,
+    "body": null
+  },
+
   "Literal": {
     "value": null
   },

src/babel/types/index.js

@@ -1,4 +1,7 @@
 import toFastProperties from "../helpers/to-fast-properties";
+import isPlainObject from "lodash/lang/isPlainObject";
+import isNumber from "lodash/lang/isNumber";
+import isRegExp from "lodash/lang/isRegExp";
 import isString from "lodash/lang/isString";
 import compact from "lodash/array/compact";
 import esutils from "esutils";
@@ -18,14 +21,14 @@ export default t;
  */
 
 function registerType(type, skipAliasCheck) {
-  var is = t["is" + type] = function (node, opts) {
+  var is = t[`is${type}`] = function (node, opts) {
     return t.is(type, node, opts, skipAliasCheck);
   };
 
-  t["assert" + type] = function (node, opts) {
+  t[`assert${type}`] = function (node, opts) {
     opts ||= {};
     if (!is(node, opts)) {
-      throw new Error("Expected type " + JSON.stringify(type) + " with option " + JSON.stringify(opts));
+      throw new Error(`Expected type ${JSON.stringify(type)} with option ${JSON.stringify(opts)}`);
     }
   };
 }
@@ -392,7 +395,7 @@ t.toIdentifier = function (name) {
   });
 
   if (!t.isValidIdentifier(name)) {
-    name = "_" + name;
+    name = `_${name}`;
   }
 
   return name || "_";
@@ -503,7 +506,7 @@ t.toStatement = function (node, ignore) {
     if (ignore) {
       return false;
     } else {
-      throw new Error("cannot turn " + node.type + " to a statement");
+      throw new Error(`cannot turn ${node.type} to a statement`);
     }
   }
 
@@ -533,7 +536,7 @@ t.toExpression = function (node) {
   if (t.isExpression(node)) {
     return node;
   } else {
-    throw new Error("cannot turn " + node.type + " to an expression");
+    throw new Error(`cannot turn ${node.type} to an expression`);
   }
 };
 
@@ -709,6 +712,10 @@ t.inherits = function (child, parent) {
   child.start         = parent.start;
   child.loc           = parent.loc;
   child.end           = parent.end;
+
+  child.typeAnnotation = parent.typeAnnotation;
+  child.returnType     = parent.returnType;
+
   t.inheritsComments(child, parent);
   return child;
 };
@@ -800,5 +807,205 @@ t.isScope = function (node, parent) {
   return t.isScopable(node);
 };
 
+/**
+ * Description
+ *
+ * @param {Node} node
+ * @returns {Boolean}
+ */
+
+t.isImmutable = function (node) {
+  if (t.isLiteral(node)) {
+    if (node.regex) {
+      // regexes are mutable
+      return false;
+    } else {
+      // immutable!
+      return true;
+    }
+  } else if (t.isIdentifier(node)) {
+    if (node.name === "undefined") {
+      // immutable!
+      return true;
+    } else {
+      // no idea...
+      return false;
+    }
+  }
+
+  return false;
+};
+
+/**
+ * Walk the input `node` and statically evaluate if it's truthy.
+ *
+ * Returning `true` when we're sure that the expression will evaluate to a
+ * truthy value, `false` if we're sure that it will evaluate to a falsy
+ * value and `undefined` if we aren't sure. Because of this please do not
+ * rely on coercion when using this method and check with === if it's false.
+ *
+ * For example do:
+ *
+ *   if (t.evaluateTruthy(node) === false) falsyLogic();
+ *
+ * **AND NOT**
+ *
+ *   if (!t.evaluateTruthy(node)) falsyLogic();
+ *
+ * @param {Node} node
+ * @param {Scope} scope
+ * @returns {Boolean}
+ */
+
+t.evaluateTruthy = function (node, scope) {
+  var res = t.evaluate(node, scope);
+  if (res.confident) return !!res.value;
+};
+
+/**
+ * Walk the input `node` and statically evaluate it.
+ *
+ * Returns an pbject in the form `{ confident, value }`. `confident` indicates
+ * whether or not we had to drop out of evaluating the expression because of
+ * hitting an unknown node that we couldn't confidently find the value of.
+ *
+ * Example:
+ *
+ *   t.evaluate(parse("5 + 5")) // { confident: true, value: 10 }
+ *   t.evaluate(parse("!true")) // { confident: true, value: false }
+ *   t.evaluate(parse("foo + foo")) // { confident: false, value: undefined }
+ *
+ * @param {Node} node
+ * @param {Scope} scope
+ * @returns {Object}
+ */
+
+t.evaluate = function (node, scope) {
+  var confident = true;
+
+  var value = evaluate(node);
+  if (!confident) value = undefined;
+  return {
+    confident: confident,
+    value:     value
+  };
+
+  function evaluate(node) {
+    if (!confident) return;
+
+    if (t.isSequenceExpression(node)) {
+      return evaluate(node.expressions[node.expressions.length - 1]);
+    }
+
+    if (t.isLiteral(node)) {
+      if (node.regex && node.value === null) {
+        // we have a regex and we can't represent it natively
+      } else {
+        return node.value;
+      }
+    }
+
+    if (t.isConditionalExpression(node)) {
+      if (evaluate(node.test)) {
+        return evaluate(node.consequent);
+      } else {
+        return evaluate(node.alternate);
+      }
+    }
+
+    if (t.isIdentifier(node)) {
+      if (node.name === "undefined") {
+        return undefined;
+      } else {
+        return evaluate(scope.getImmutableBindingValue(node.name));
+      }
+    }
+
+    if (t.isUnaryExpression(node, { prefix: true })) {
+      var arg = evaluate(node.argument);
+      switch (node.operator) {
+        case "void": return undefined;
+        case "!": return !arg;
+        case "+": return +arg;
+        case "-": return -arg;
+      }
+    }
+
+    if (t.isArrayExpression(node) || t.isObjectExpression(node)) {
+      // we could evaluate these but it's probably impractical and not very useful
+    }
+
+    if (t.isLogicalExpression(node)) {
+      var left = evaluate(node.left);
+      var right = evaluate(node.right);
+
+      switch (node.operator) {
+        case "||": return left || right;
+        case "&&": return left && right;
+      }
+    }
+
+    if (t.isBinaryExpression(node)) {
+      var left = evaluate(node.left);
+      var right = evaluate(node.right);
+
+      switch (node.operator) {
+        case "-": return left - right;
+        case "+": return left + right;
+        case "/": return left / right;
+        case "*": return left * right;
+        case "%": return left % right;
+        case "<": return left < right;
+        case ">": return left > right;
+        case "<=": return left <= right;
+        case ">=": return left >= right;
+        case "==": return left == right;
+        case "!=": return left != right;
+        case "===": return left === right;
+        case "!==": return left !== right;
+      }
+    }
+
+    confident = false;
+  }
+};
+
+/**
+ * Description
+ *
+ * @param value
+ * @returns {Node}
+ */
+
+t.valueToNode = function (value) {
+  if (value === undefined) {
+    return t.identifier("undefined");
+  }
+
+  if (value === true || value === false || value === null || isString(value) || isNumber(value) || isRegExp(value)) {
+    return t.literal(value);
+  }
+
+  if (Array.isArray(value)) {
+    return t.arrayExpression(value.map(t.valueToNode));
+  }
+
+  if (isPlainObject(value)) {
+    var props = [];
+    for (var key in value) {
+      var nodeKey;
+      if (t.isValidIdentifier(key)) {
+        nodeKey = t.identifier(key);
+      } else {
+        nodeKey = t.literal(key);
+      }
+      props.push(t.property("init", nodeKey, t.valueToNode(value[key])));
+    }
+    return t.objectExpression(props);
+  }
+
+  throw new Error("don't know how to turn this value into a node");
+};
+
 toFastProperties(t);
 toFastProperties(t.VISITOR_KEYS);

src/babel/types/visitor-keys.json

@@ -1,7 +1,7 @@
 {
   "ArrayExpression":           ["elements"],
-  "ArrayPattern":              ["elements"],
-  "ArrowFunctionExpression":   ["params", "defaults", "rest", "body"],
+  "ArrayPattern":              ["elements", "typeAnnotation"],
+  "ArrowFunctionExpression":   ["params", "defaults", "rest", "body", "returnType"],
   "AssignmentExpression":      ["left", "right"],
   "AssignmentPattern":         ["left", "right"],
   "AwaitExpression":           ["argument"],
@@ -13,8 +13,8 @@
   "CallExpression":            ["callee", "arguments"],
   "CatchClause":               ["param", "body"],
   "ClassBody":                 ["body"],
-  "ClassDeclaration":          ["id", "body", "superClass"],
-  "ClassExpression":           ["id", "body", "superClass"],
+  "ClassDeclaration":          ["id", "body", "superClass", "typeParameters", "superTypeParameters", "implements"],
+  "ClassExpression":           ["id", "body", "superClass", "typeParameters", "superTypeParameters", "implements"],
   "ComprehensionBlock":        ["left", "right", "body"],
   "ComprehensionExpression":   ["filter", "blocks", "body"],
   "ConditionalExpression":     ["test", "consequent", "alternate"],
@@ -30,9 +30,9 @@
   "ForInStatement":            ["left", "right", "body"],
   "ForOfStatement":            ["left", "right", "body"],
   "ForStatement":              ["init", "test", "update", "body"],
-  "FunctionDeclaration":       ["id", "params", "defaults", "rest", "body"],
-  "FunctionExpression":        ["id", "params", "defaults", "rest", "body"],
-  "Identifier":                [],
+  "FunctionDeclaration":       ["id", "params", "defaults", "rest", "body", "returnType", "typeParameters"],
+  "FunctionExpression":        ["id", "params", "defaults", "rest", "body", "returnType", "typeParameters"],
+  "Identifier":                ["typeAnnotation"],
   "IfStatement":               ["test", "consequent", "alternate"],
   "ImportBatchSpecifier":      ["id"],
   "ImportDeclaration":         ["specifiers", "source"],
@@ -44,11 +44,11 @@
   "MethodDefinition":          ["key", "value"],
   "NewExpression":             ["callee", "arguments"],
   "ObjectExpression":          ["properties"],
-  "ObjectPattern":             ["properties"],
+  "ObjectPattern":             ["properties", "typeAnnotation"],
   "PrivateDeclaration":        ["declarations"],
   "Program":                   ["body"],
   "Property":                  ["key", "value"],
-  "RestElement":               ["argument"],
+  "RestElement":               ["argument", "typeAnnotation"],
   "ReturnStatement":           ["argument"],
   "SequenceExpression":        ["expressions"],
   "SpreadElement":             ["argument"],
@@ -71,36 +71,37 @@
   "YieldExpression":           ["argument"],
 
   "AnyTypeAnnotation":           [],
-  "ArrayTypeAnnotation":         [],
+  "ArrayTypeAnnotation":         ["elementType"],
   "BooleanTypeAnnotation":       [],
-  "ClassProperty":               ["key", "value"],
-  "DeclareClass":                [],
-  "DeclareFunction":             [],
-  "DeclareModule":               [],
-  "DeclareVariable":             [],
-  "FunctionTypeAnnotation":      [],
-  "FunctionTypeParam":           [],
-  "GenericTypeAnnotation":       [],
-  "InterfaceExtends":            [],
-  "InterfaceDeclaration":        [],
-  "IntersectionTypeAnnotation":  [],
-  "NullableTypeAnnotation":      [],
+  "ClassImplements":             ["id", "typeParameters"],
+  "ClassProperty":               ["key", "value", "typeAnnotation"],
+  "DeclareClass":                ["id", "typeParameters", "extends", "body"],
+  "DeclareFunction":             ["id"],
+  "DeclareModule":               ["id", "body"],
+  "DeclareVariable":             ["id"],
+  "FunctionTypeAnnotation":      ["typeParameters", "params", "rest", "returnType"],
+  "FunctionTypeParam":           ["name", "typeAnnotation"],
+  "GenericTypeAnnotation":       ["id", "typeParameters"],
+  "InterfaceExtends":            ["id", "typeParameters"],
+  "InterfaceDeclaration":        ["id", "typeParameters", "extends", "body"],
+  "IntersectionTypeAnnotation":  ["types"],
+  "NullableTypeAnnotation":      ["typeAnnotation"],
   "NumberTypeAnnotation":        [],
   "StringLiteralTypeAnnotation": [],
   "StringTypeAnnotation":        [],
-  "TupleTypeAnnotation":         [],
-  "TypeofTypeAnnotation":        [],
-  "TypeAlias":                   [],
-  "TypeAnnotation":              [],
+  "TupleTypeAnnotation":         ["types"],
+  "TypeofTypeAnnotation":        ["argument"],
+  "TypeAlias":                   ["id", "typeParameters", "right"],
+  "TypeAnnotation":              ["typeAnnotation"],
   "TypeCastExpression":          ["expression"],
-  "TypeParameterDeclaration":    [],
-  "TypeParameterInstantiation":  [],
-  "ObjectTypeAnnotation":        [],
-  "ObjectTypeCallProperty":      [],
-  "ObjectTypeIndexer":           [],
-  "ObjectTypeProperty":          [],
-  "QualifiedTypeIdentifier":     [],
-  "UnionTypeAnnotation":         [],
+  "TypeParameterDeclaration":    ["params"],
+  "TypeParameterInstantiation":  ["params"],
+  "ObjectTypeAnnotation":        ["key", "value"],
+  "ObjectTypeCallProperty":      ["value"],
+  "ObjectTypeIndexer":           ["id", "key", "value"],
+  "ObjectTypeProperty":          ["key", "value"],
+  "QualifiedTypeIdentifier":     ["id", "qualification"],
+  "UnionTypeAnnotation":         ["types"],
   "VoidTypeAnnotation":          [],
 
   "JSXAttribute":              ["name", "value"],

src/babel/util.js

@@ -15,12 +15,12 @@ import has from "lodash/object/has";
 import fs from "fs";
 import t from "./types";
 
-export { inherits } from "util";
+export { inherits, inspect } from "util";
 
 export var debug = buildDebug("babel");
 
 export function canCompile(filename, altExts) {
-  var exts = altExts || exports.canCompile.EXTENSIONS;
+  var exts = altExts || canCompile.EXTENSIONS;
   var ext = path.extname(filename);
   return contains(exts, ext);
 }
@@ -50,7 +50,7 @@ export function regexify(val) {
 export function arrayify(val) {
   if (!val) return [];
   if (isBoolean(val)) return [val];
-  if (isString(val)) return exports.list(val);
+  if (isString(val)) return list(val);
   if (Array.isArray(val)) return val;
   throw new TypeError("illegal type for arrayify");
 }
@@ -75,7 +75,7 @@ var templateVisitor = {
 
 export function template(name, nodes, keepExpression) {
   var ast = exports.templates[name];
-  if (!ast) throw new ReferenceError("unknown template " + name);
+  if (!ast) throw new ReferenceError(`unknown template ${name}`);
 
   if (nodes === true) {
     keepExpression = true;

test/_helper.js

@@ -24,7 +24,7 @@ exports.esvalid = function (ast, code, loc) {
   if (errors.length) {
     var msg = [];
     _.each(errors, function (err) {
-      msg.push(err.message + " - " + JSON.stringify(err.node));
+      msg.push(err.message + " - " + util.inspect(err.node));
     });
     throw new Error(loc + ": " + msg.join(". ") + "\n" + code);
   }

test/_transformation-helper.js

@@ -97,7 +97,7 @@ var run = function (task, done) {
   if (!execCode || actualCode) {
     result     = transform(actualCode, getOpts(actual));
     checkAst(result, actual);
-    actualCode = result.code;
+    actualCode = result.code.trim();
 
     try {
       chai.expect(actualCode).to.be.equal(expectCode, actual.loc + " !== " + expect.loc);

test/fixtures/generation/flow/array-types/actual.js

@@ -0,0 +1,6 @@
+var a: number[];
+var a: ?number[];
+var a: (?number)[];
+var a: () => number[];
+var a: (() => number)[];
+var a: typeof A[];

test/fixtures/generation/flow/array-types/expected.js

@@ -0,0 +1,6 @@
+var a: number[];
+var a: ?number[];
+var a: (?number)[];
+var a: () => number[];
+var a: (() => number)[];
+var a: typeof A[];

test/fixtures/generation/flow/call-properties/actual.js

@@ -0,0 +1,5 @@
+var a: { (): number };
+var a: { (): number; };
+var a: { (): number; y: string; (x: string): string };
+var a: { <T>(x: T): number; };
+interface A { (): number; };

test/fixtures/generation/flow/call-properties/expected.js

@@ -0,0 +1,5 @@
+var a: { (): number };
+var a: { (): number };
+var a: { y: string; (): number; (x: string): string };
+var a: { <T>(x: T): number };
+interface A { (): number };

test/fixtures/generation/flow/declare-module/actual.js

@@ -0,0 +1,5 @@
+declare module A {}
+declare module "./a/b.js" {}
+declare module A { declare var x: number; }
+declare module A { declare function foo(): number; }
+declare module A { declare class B { foo(): number; } }

test/fixtures/generation/flow/declare-module/expected.js

@@ -0,0 +1,11 @@
+declare module A {}
+declare module "./a/b.js" {}
+declare module A {
+  declare var x: number;
+}
+declare module A {
+  declare function foo(): number;
+}
+declare module A {
+  declare class B { foo(): number }
+}

test/fixtures/generation/flow/declare-statements/actual.js

@@ -0,0 +1,11 @@
+declare var foo
+declare var foo;
+declare function foo(): void
+declare function foo(): void;
+declare function foo<T>(): void;
+declare function foo(x: number, y: string): void;
+declare class A {}
+declare class A<T> extends B<T> { x: number }
+declare class A { static foo(): number; static x : string }
+declare class A { static [ indexer: number]: string }
+declare class A { static () : number }

test/fixtures/generation/flow/declare-statements/expected.js

@@ -0,0 +1,11 @@
+declare var foo;
+declare var foo;
+declare function foo(): void;
+declare function foo(): void;
+declare function foo<T>(): void;
+declare function foo(x: number, y: string): void;
+declare class A {}
+declare class A<T> extends B<T> { x: number }
+declare class A { static foo(): number; static x: string }
+declare class A { static [indexer: number]: string }
+declare class A { static (): number }

test/fixtures/generation/flow/interfaces-module-and-script/actual.js

@@ -0,0 +1,9 @@
+interface A {};
+interface A extends B {};
+interface A<T> extends B<T>, C<T> {};
+interface A { foo: () => number; };
+interface Dictionary { [index: string]: string; length: number; };
+class Foo implements Bar {}
+class Foo extends Bar implements Bat, Man<number> {}
+class Foo extends class Bar implements Bat {} {}
+class Foo extends class Bar implements Bat {} implements Man {}

test/fixtures/generation/flow/interfaces-module-and-script/expected.js

@@ -0,0 +1,9 @@
+interface A {};
+interface A extends B {};
+interface A<T> extends B<T>, C<T> {};
+interface A { foo(): number };
+interface Dictionary { length: number; [index: string]: string };
+class Foo implements Bar {}
+class Foo extends Bar implements Bat, Man<number> {}
+class Foo extends class Bar implements Bat {} {}
+class Foo extends class Bar implements Bat {} implements Man {}

test/fixtures/generation/flow/qualified-generic-type/actual.js

@@ -0,0 +1,4 @@
+var a: A.B;
+var a: A.B.C;
+var a: A.B<T>;
+var a: typeof A.B<T>;

test/fixtures/generation/flow/qualified-generic-type/expected.js

@@ -0,0 +1,4 @@
+var a: A.B;
+var a: A.B.C;
+var a: A.B<T>;
+var a: typeof A.B<T>;

test/fixtures/generation/flow/string-literal-types/actual.js

@@ -0,0 +1,2 @@
+function createElement(tagName: "div"): HTMLDivElement {}
+function createElement(tagName: 'div'): HTMLDivElement {}

test/fixtures/generation/flow/string-literal-types/expected.js

@@ -0,0 +1,2 @@
+function createElement(tagName: "div"): HTMLDivElement {}
+function createElement(tagName: "div"): HTMLDivElement {}

test/fixtures/generation/flow/tuples/actual.js

@@ -0,0 +1,4 @@
+var a: [] = [];
+var a: [Foo<T>] = [foo];
+var a: [number,] = [123,];
+var a: [number, string] = [123, "duck"];

test/fixtures/generation/flow/tuples/expected.js

@@ -0,0 +1,4 @@
+var a: [] = [];
+var a: [Foo<T>] = [foo];
+var a: [number] = [123];
+var a: [number, string] = [123, "duck"];

test/fixtures/generation/flow/type-alias/actual.js

@@ -0,0 +1,3 @@
+type FBID = number;
+type Foo<T> = Bar<T>
+export type Foo = number;

test/fixtures/generation/flow/type-alias/expected.js

@@ -0,0 +1,3 @@
+type FBID = number;
+type Foo<T> = Bar<T>;
+export type Foo = number;

test/fixtures/generation/flow/type-annotations/actual.js

@@ -0,0 +1,97 @@
+function foo(numVal: any) {}
+function foo(numVal: number) {}
+function foo(numVal: number, strVal: string) {}
+function foo(numVal: number, untypedVal) {}
+function foo(untypedVal, numVal: number) {}
+function foo(nullableNum: ?number) {}
+function foo(callback: () => void) {}
+function foo(callback: () => number) {}
+function foo(callback: (_: bool) => number) {}
+function foo(callback: (_1: bool, _2: string) => number) {}
+function foo(callback: (_1: bool, ...foo: Array<number>) => number) {}
+function foo(): number{}
+function foo():() => void {}
+function foo():(_:bool) => number{}
+function foo():(_?:bool) => number{}
+function foo(): {} {}
+function foo<T>() {}
+function foo<T,S>() {}
+a = function<T,S>() {};
+a = { set fooProp(value: number) {} };
+a = { set fooProp(value: number): void {} };
+a = { get fooProp():number{} };
+a = { id<T>(x: T): T {} };
+a = { *id<T>(x: T): T {} };
+a = { async id<T>(x: T): T {} };
+a = { 123<T>(x: T): T {} };
+class Foo {
+  set fooProp(value: number) {}
+}
+class Foo {
+  set fooProp(value: number): void {}
+}
+class Foo {
+  get fooProp(): number {}
+}
+var numVal: number;
+var numVal: number = otherNumVal;
+var a: { numVal: number };
+var a: { numVal: number; };
+var a: { numVal: number; [indexer: string]: number };
+var a: ?{ numVal: number };
+var a: { numVal: number; strVal: string }
+var a: { subObj: {strVal: string} }
+var a: { subObj: ?{strVal: string} }
+var a: { param1: number; param2: string }
+var a: { param1: number; param2?: string }
+var a: { [a: number]: string; [b: number]: string; };
+var a: { add(x: number, ...y: Array<string>): void };
+var a: { id<T>(x: T): T; };
+var a:Array<number> = [1, 2, 3]
+a = class Foo<T> {}
+a = class Foo<T> extends Bar<T> {}
+class Foo<T> {}
+class Foo<T> extends Bar<T> {}
+class Foo<T> extends mixin(Bar) {}
+class Foo<T> {
+  bar<U>():number { return 42; }
+}
+class Foo {
+  "bar"<T>() {}
+}
+function foo(requiredParam, optParam?) {}
+class Foo {
+  prop1: string;
+  prop2: number;
+}
+class Foo {
+  static prop1: string;
+  prop2: number;
+}
+var x: number | string = 4;
+class Array { concat(items:number | string) {}; }
+var x: () => number | () => string = fn;
+var x: typeof Y = Y;
+var x: typeof Y | number = Y;
+var {x}: {x: string; } = { x: "hello" };
+var {x}: {x: string } = { x: "hello" };
+var [x]: Array<string> = [ "hello" ];
+function foo({x}: { x: string; }) {}
+function foo([x]: Array<string>) {}
+function foo(...rest: Array<number>) {}
+(function (...rest: Array<number>) {});
+((...rest: Array<number>) => rest);
+var a: Map<string, Array<string> >
+var a: Map<string, Array<string>>
+var a: number[]
+var a: ?string[]
+var a: Promise<bool>[]
+var a:(...rest:Array<number>) => number
+var identity: <T>(x: T) => T
+var identity: <T>(x: T, ...y:T[]) => T
+import type foo from "bar";
+import type { foo, bar } from "baz";
+import type { foo as bar } from "baz";
+import type from "foo";
+import type, { foo } from "bar";
+import type * as namespace from "bar";

test/fixtures/generation/flow/type-annotations/expected.js

@@ -0,0 +1,101 @@
+function foo(numVal: any) {}
+function foo(numVal: number) {}
+function foo(numVal: number, strVal: string) {}
+function foo(numVal: number, untypedVal) {}
+function foo(untypedVal, numVal: number) {}
+function foo(nullableNum: ?number) {}
+function foo(callback: () => void) {}
+function foo(callback: () => number) {}
+function foo(callback: (_: bool) => number) {}
+function foo(callback: (_1: bool, _2: string) => number) {}
+function foo(callback: (_1: bool, ...foo: Array<number>) => number) {}
+function foo(): number {}
+function foo(): () => void {}
+function foo(): (_: bool) => number {}
+function foo(): (_?: bool) => number {}
+function foo(): {} {}
+function foo<T>() {}
+function foo<T, S>() {}
+a = function <T, S>() {};
+a = { set fooProp(value: number) {} };
+a = { set fooProp(value: number): void {} };
+a = { get fooProp(): number {} };
+a = { id<T>(x: T): T {} };
+a = { *id<T>(x: T): T {} };
+a = { async id<T>(x: T): T {} };
+a = { 123<T>(x: T): T {} };
+class Foo {
+  set fooProp(value: number) {}
+}
+class Foo {
+  set fooProp(value: number): void {}
+}
+class Foo {
+  get fooProp(): number {}
+}
+var numVal: number;
+var numVal: number = otherNumVal;
+var a: { numVal: number };
+var a: { numVal: number };
+var a: { numVal: number; [indexer: string]: number };
+var a: ?{ numVal: number };
+var a: { numVal: number; strVal: string };
+var a: { subObj: { strVal: string } };
+var a: { subObj: ?{ strVal: string } };
+var a: { param1: number; param2: string };
+var a: { param1: number; param2?: string };
+var a: { [a: number]: string; [b: number]: string };
+var a: { add(x: number, ...y: Array<string>): void };
+var a: { id<T>(x: T): T };
+var a: Array<number> = [1, 2, 3];
+a = class Foo<T> {};
+a = class Foo<T> extends Bar<T> {};
+class Foo<T> {}
+class Foo<T> extends Bar<T> {}
+class Foo<T> extends mixin(Bar) {}
+class Foo<T> {
+  bar<U>(): number {
+    return 42;
+  }
+}
+class Foo {
+  "bar"<T>() {}
+}
+function foo(requiredParam, optParam?) {}
+class Foo {
+  prop1: string;
+  prop2: number;
+}
+class Foo {
+  static prop1: string;
+  prop2: number;
+}
+var x: number | string = 4;
+class Array {
+  concat(items: number | string) {}
+}
+var x: () => number | () => string = fn;
+var x: typeof Y = Y;
+var x: typeof Y | number = Y;
+var { x }: { x: string } = { x: "hello" };
+var { x }: { x: string } = { x: "hello" };
+var [x]: Array<string> = ["hello"];
+function foo({ x }: { x: string }) {}
+function foo([x]: Array<string>) {}
+function foo(...rest: Array<number>) {}
+(function (...rest: Array<number>) {});
+(...rest: Array<number>) => rest;
+var a: Map<string, Array<string>>;
+var a: Map<string, Array<string>>;
+var a: number[];
+var a: ?string[];
+var a: Promise<bool>[];
+var a: (...rest: Array<number>) => number;
+var identity: <T>(x: T) => T;
+var identity: <T>(x: T, ...y: T[]) => T;
+import type foo from "bar";
+import type { foo, bar } from "baz";
+import type { foo as bar } from "baz";
+import type from "foo";
+import type, { foo } from "bar";
+import type * as namespace from "bar";

test/fixtures/generation/flow/typecasts/actual.js

@@ -0,0 +1,4 @@
+(xxx: number);
+({ xxx: 0, yyy: "hey" }: { xxx: number; yyy: string });
+(xxx => xxx + 1: (xxx: number) => number);
+((xxx: number), (yyy: string));

test/fixtures/generation/flow/typecasts/expected.js

@@ -0,0 +1,4 @@
+(xxx: number);
+({ xxx: 0, yyy: "hey" }: { xxx: number; yyy: string });
+(xxx => xxx + 1: (xxx: number) => number);
+(xxx: number), (yyy: string);

test/fixtures/transformation/es6-block-scoping-tdz-fail/destructuring.js

@@ -0,0 +1,9 @@
+function foo(
+   { x: { y: { z: a = b } = {}, w: b = 20 }, a: c = 30 }
+) {
+  assert.equal(a, 10);
+  assert.equal(b, 20);
+  assert.equal(c, 30);
+}
+
+foo({ x: {} });

test/fixtures/transformation/es6-block-scoping-tdz-pass/destructuring.js

@@ -0,0 +1,9 @@
+function foo(
+   { x: { y: { z: a = 10 } = {}, w: b = 20 }, a: c = 30 }
+) {
+  assert.equal(a, 10);
+  assert.equal(b, 20);
+  assert.equal(c, 30);
+}
+
+foo({ x: {} });

test/fixtures/transformation/es6-block-scoping/wrap-closure-shadow-variables/actual.js

@@ -0,0 +1,5 @@
+let a = 1;
+for (let a = 1; a < 100; a++) {
+  items.forEach(item => a);
+}
+console.log(a);