v5.6.12

This is necessary in order to retain correct function arity and to have
completely correct semantics. Sometimes features are tied together so much
that they would require so much desugaring to retain the correct semantics
that they'd be equivalent to... the normal transpiled output.

.babelrc

@@ -2,5 +2,6 @@
   "stage": 0,
   "loose": ["all"],
   "blacklist": ["es6.tailCall"],
-  "optional": ["optimisation.flow.forOf"]
+  "optional": ["optimisation.flow.forOf"],
+  "plugins": ["./tools/build-plugins/protect"]
 }

.eslintrc

@@ -3,18 +3,23 @@
   "rules": {
     "strict": 0,
     "no-underscore-dangle": 0,
-    "no-unused-vars": 0,
     "curly": 0,
     "no-multi-spaces": 0,
     "key-spacing": 0,
     "no-return-assign": 0,
     "consistent-return": 0,
     "no-shadow": 0,
-    "no-comma-dangle": 0,
+    "comma-dangle": 0,
     "no-use-before-define": 0,
     "no-empty": 0,
     "new-parens": 0,
-    "no-cond-assign": 0
+    "no-cond-assign": 0,
+    "no-fallthrough": 0,
+    "new-cap": 0,
+    "no-loop-func": 0,
+    "no-unreachable": 0,
+    "no-labels": 0,
+    "no-process-exit": 0
   },
   "env": {
     "node": true

.gitignore

@@ -8,10 +8,10 @@ test/core/tmp
 /browser.js
 /browser-polyfill.js
 /runtime.js
-coverage
+/coverage
-dist
+/dist
-.package.json
+/.package.json
-packages/babel-runtime/core-js
+/packages/babel-runtime/core-js
-packages/babel-runtime/helpers/*.js
+/packages/babel-runtime/helpers/*.js
-packages/babel-runtime/regenerator/*.js
+/packages/babel-runtime/regenerator/*.js
-lib
+/lib

.travis.yml

@@ -11,9 +11,4 @@ before_script: "npm install -g codeclimate-test-reporter"
 script: "make test-travis"
 
 notifications:
-  webhooks:
+  slack: babeljs:5Wy4QX13KVkGy9CnU0rmvgeK
-    urls:
-      - https://webhooks.gitter.im/e/acf1870e9d223c65e8d5
-    on_success: always
-    on_failure: always
-    on_start: false

CHANGELOG.md

@@ -13,6 +13,215 @@ _Note: Gaps between patch versions are faulty/broken releases._
 
 See [CHANGELOG - 6to5](CHANGELOG-6to5.md) for the pre-4.0.0 version changelog.
 
+## 5.6.12
+
+ * **Bug Fix**
+  * Fix finding parent for top-level shadowed functions.
+
+## 5.6.11
+
+ ** **Internal**
+  * Merge `es6.parameters.rest` and `es6.parameters.default` transformers. See commit [c0fd4c1f9e0b18231f585c4fa793e4cb0e01aed1](https://github.com/babel/babel/commit/c0fd4c1f9e0b18231f585c4fa793e4cb0e01aed1) for more info.
+
+## 5.6.10
+
+ * **Bug Fix**
+  * Fix faulty internal require check.
+ * **Polish**
+  * Add support for trailing commas in arrow function parameter lists.
+
+## 5.6.8
+
+ * **Bug Fix**
+  * Fix binary expressions colliding with unary expression operators in compact mode.
+  * Fix node properties being set to `null` when using computed properties.
+
+## 5.6.7
+
+ * **Bug Fix**
+  * Fix hoisting of `ForXStatement` `left` `var`s when inserting a block scoping IIFE.
+ * **Polish**
+  * Combine all leading computed property initialisers into the root object in loose mode.
+ * **Internal**
+  * Deprecate returning of replacement strings from visitor methods.
+
+## 5.6.6
+
+ * **Bug Fix**
+  * Fix weird parser bug where `void` type annotations were being parsed as keywords causing the tokeniser to lose track of context.
+
+## 5.6.5
+
+ * **Bug Fix**
+  * Fix nested functions causing rest parameter optimisation to not properly detect when it should deopt on a reference.
+ * **Internal**
+  * Update Regenerator `0.8.31`.
+
+## 5.6.4
+
+ * **Internal**
+  * Add `ParenthesizedExpression` node type.
+
+## 5.6.3
+
+ * **Bug Fix**
+  * Fix rest parameter array allocation loop being incorrectly aliased.
+
+## 5.6.2
+
+ * **Bug Fix**
+  * Fix method key literals not turning into computed member expression in loose mode.
+  * Elect rest parameters in spread element position as candidates instead of replacing them in place.
+
+## 5.6.0
+
+ * **Bug Fix**
+  * Fix istanbul interop for register hook when registering for non-existence extension.
+  * Fix super class constructor call differing for no constructor in derived classes.
+  * Disable module import receiver when in loose mode.
+  * Fix duplicate filenames when using `babel` CLI when passing multiple matching patterns.
+  * Register labels as bindings to fix undeclared variable checks.
+ * **Polish**
+  * Remove unnecessary string binary expressions when transforming template literals.
+  * Support module live bindings in arbitary positions not in Program statement position.
+  * Throw error when attemping to replace a `Program` root node with another node not of type `Program`.
+  * Optimise rest parameters in spread element position and allocate rest array at the earliest common ancestor of all references.
+  * Generate original number representation when value was not changed.
+  * Check for invalid binding identifiers when generating inferred method names.
+  * Don't terminate CLI when watching files fail compilation on init.
+ * **New Feature**
+  * Add new plugin API.
+ * **Internal**
+  * Split react displayName addition into a plugin.
+  * Add check for `JSXMemberExpression` to `t.isReferenced`.
+  * Move `validation.undeclaredVariableCheck` transformer up.
+  * Start great core-to-plugin exodus.
+  * Add `BindingIdentifier` virtual type.
+  * Hidden class optimisations.
+  * Array allocation optimisations.
+  * Update `regenerator`.
+  * Update `js-tokens`.
+  * Sync with upstream Acorn.
+
+## 5.5.8
+
+ * **Internal**
+  * Remove extremely unprofessional and harsh error message for those hotlinking to `resolve-rc`.
+
+## 5.5.7
+
+ * **Bug Fix**
+  * Push newline after decorators when doing code gen.
+  * Rewriting error handling to normalise options before merging them.
+  * Remove duplicate keys in `alias-keys.json` causing errors in strict mode.
+  * Fix `$ babel --help` not showing optional transformers as such.
+ * **New Feature**
+  * Add `auxiliaryCommentBefore` and `auxiliaryCommentAfter` options.
+
+## 5.5.6
+
+ * **Bug Fix**
+  * Fix `let` binding collision in loop head not properly replacing `AssignmentExpression`s.
+
+## 5.5.5
+
+ * **Bug Fix**
+  * Fix `file.opts` not being set before `file.log.deprecate` was called causing a `ReferenceError` as it was checking for a property on it.
+
+## 5.5.4
+
+ * **Bug Fix**
+  * Add back missing `shouldIgnore` check.
+  * Log message on deprecated options rather than throw an error.
+  * Fix name of `auxiliaryComment` option when attempting Istanbul interop in `babel/register`.
+
+## 5.5.3
+
+ * **Bug Fix**
+  * Fix weird state bug when traversing overa  `node` `ClassProperty` instead of `path` in the `es6.classes` transformer.
+
+## 5.5.2
+
+ * **Bug Fix**
+  * Fix `NodePath#isPure` on `Property` nodes.
+  * Use cwd instead of entry file directory when working out relative directory for `babel/register`.
+ * **Internal**
+  * Add scary warning for those few who choose to use the WIP experimental transformers.
+
+## 5.5.1
+
+ * **Bug Fix**
+  * Remove `ClassProperty` nodes always in the `Flow` transformer. This is fine now since class properties aren't supported in any engine that supports classes but the `es7.classProperties` transformer will need to be updated in the future to desugar to ES6 classes instead of relying on the `es6.classes` transformer from being ran.
+
+## 5.5.0
+
+ * **Bug Fix**
+  * Allow pushing declarations to `SwitchStatement`s.
+  * Fix `minification.removeDebugger` to remove `DebuggerStatement`s rather than `ExpressionStatement`s with an identifier of `debugger`.
+  * Check LHS in `ForInStatement` and `ForOfStatement` for constant violations.
+  * Register function `id` as a reference when naming methods to avoid collisions.
+  * Support key literals when checking for the existence of `displayName` property when attempting to add it for `React.createClass`.
+  * Remove `ExportDefaultSpecifier` check from `t.isDefaultSpecifier`.
+  * Don't consider `JSXIdentifier` HTML tag identifiers to be references.
+ * **Polish**
+  * Update `minification.deadCodeElimination` transformer to remove all statements after completion statements.
+  * Update `minification.deadCodeElimination` transformer to not inline single used bindings that exist in different scopes.
+  * When performing Istanbul interop in `babel/register`, add the auxiliary comment `"istanbul ignore text"` to get more accurate coverage.
+  * Add `--nolazy` argument to `babel-node`.
+  * Add support for `cluster` forking.
+  * Perform scope tracking in a single pass instead of multiple.
+  * Smarten up type inferrence and resolution to support the whole array of language constructs.
+  * Optimise module metadata retrieval into a single pass.
+  * Ignore trailing commas when inferring newlines.
+  * Rename `minification.inlineExpressions` transformer to `minification.constantFolding`.
+  * Check path relative to entry file when checking to see if we're inside `node_modules` when using `babel/register`.
+  * Upgrade `regenerator`.
+
+## 5.4.7
+
+ * **Bug Fix**
+  * Don't consider `JSXAttribute` `names` to be valid `ReferencedIdentifier`s.
+
+## 5.4.6
+
+ * **Bug Fix**
+  * Fix `spec.functionName` transformer incorrectly attempting to rename a binding that doesn't exist as it's a global.
+ * **Internal**
+  * Deprecate custom module formatters.
+
+## 5.4.5
+
+ * **Bug Fix**
+  * Add `JSXIdentifier` as a valid `ReferencedIdentifier` visitor virtual type.
+  * Ignore `CallExpression` `_prettyCall` when the `retainLines` option is enabled.
+  * Inherit comments to new declaration node when exploding module declarations.
+  * Fix `es6.tailCall` transformer failing on calls that exceed the max parameters of the function.
+
+## 5.4.4
+
+ * **Bug Fix**
+  * Fix bug where replacing variable declarations in the head of a `for` loop would turn them into `ExpressionStatement`s.
+  * Fix renaming of assignment expressions that were non-identifiers ie. patterns.
+  * Force space before `class` `id` to avoid breaking named classes when using `compact` mode.
+  * Add assignment pattern explosion to avoid initial duplicate nodes.
+  * Ignore this and arguments when performing TCO on shadowed functions.
+ * **Polish**
+  * Rename `sourceMapName` option to `sourceMapTarget`. Thanks [@getify](https://github.com/getify)!
+  * Better detection of completion records, ignore those in `Function`s.
+  * Clarified descriptions of the options that are enabled by default.
+  * Resolve `\`babel-plugin-${name}\`` plugin names **before** just checking the `name`. Thanks [@jquense](https://github.com/jquense)!
+  * Update AMD module formatter to add import default remapping.
+
+## 5.4.3
+
+ * **Bug Fix**
+  * Fix `module` being incorrectly rewritten when used as in an export declaration.
+  * When performing single-reference inlining, ensure that the single reference isn't a child of the binding itself.
+  * Fix a bug in `minification.deadCodeElimination` where a new binding instance was being created for local class bindings instead of just inheriting the parent one.
+  * Fix bug with paren printing in `compact` and `retainLines` mode where a left paren was already printed before catching up.
+ * **Internal**
+  * Handle contexts for paths much better. This will ensure that the path node location info is in sync.
+
 ## 5.4.2
 
  * **Polish**

CONTRIBUTING.md

@@ -1,3 +1,7 @@
+# NOTE: BEFORE OPENING AN ISSUE PLEASE SEE THE [README](https://github.com/babel/babel#readme).
+
+----
+
 <p align="center">
    <strong><a href="#setup">Setup</a></strong>
    |
@@ -8,6 +12,8 @@
    <strong><a href="#dependencies">Dependencies</a></strong>
    |
    <strong><a href="#code-standards">Code Standards</a></strong>
+   |
+   <strong><a href="#internals">Internals</a></strong>
 </p>
 
 ----
@@ -18,9 +24,11 @@ Contributions are always welcome, no matter how large or small. Before
 contributing, please read the
 [code of conduct](https://github.com/babel/babel/blob/master/CODE_OF_CONDUCT.md).
 
-
 ## Developing
 
+> Note: Babel moves fast. Only the latest release is guaranteed to build correctly.
+> Older releases are not officially supported. If you attempt to build them, do that at your own risk.
+
 #### Setup
 
 ```sh
@@ -79,7 +87,6 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
 * Ensure the test are passing (`make test`)
 * Create new pull request explaining your proposed change or reference an issue in your commit message
 
-
 #### Dependencies
 
 + [ast-types](http://ghub.io/ast-types) This is required to monkeypatch regenerators AST definitions. Could be improved in the future.
@@ -106,8 +113,6 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
 
 + [js-tokens](http://ghub.io/js-tokens) This is used to get tokens for syntax error highlighting.
 
-+ [leven](http://ghub.io/leven) A levenstein algorithm to determine how close a word is to another. This is used to offer suggestions when using the utility.undeclaredVariableCheck transformer.
-
 + [line-numbers](http://ghub.io/line-numbers) Used to produce the code frames in syntax errors.
 
 + [lodash](http://ghub.io/lodash) Used for various utilities.
@@ -167,3 +172,6 @@ your [`$PATH`](http://unix.stackexchange.com/questions/26047/how-to-correctly-ad
  * **Declaration**
    * No unused variables
    * No pollution of global variables and prototypes
+
+#### Internals
+Please see [`/doc`](/doc) for internals documentation relevant to developing babel.

Makefile

@@ -5,6 +5,7 @@ UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs
 #UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs --mangle sort
 MOCHA_CMD = node_modules/mocha/bin/_mocha
 BABEL_CMD = node_modules/babel/bin/babel
+BROWSERIFY_IGNORE = -i esprima-fb
 
 export NODE_ENV = test
 
@@ -14,7 +15,7 @@ build-core: clean-core
 	node $(BABEL_CMD) src --out-dir lib --copy-files
 
 build-core-test: clean-core
-	node $(BABEL_CMD) src --out-dir lib --copy-files --auxiliary-comment "istanbul ignore next"
+	node $(BABEL_CMD) src --out-dir lib --copy-files --auxiliary-comment-before "istanbul ignore next"
 
 watch-core: clean-core
 	node $(BABEL_CMD) src --out-dir lib --watch --copy-files
@@ -22,6 +23,9 @@ watch-core: clean-core
 clean-core:
 	rm -rf lib
 
+lint:
+	eslint src/babel packages/babel-cli/bin
+
 build:
 	mkdir -p dist
 	make build-core
@@ -31,8 +35,10 @@ build:
 	node $(BROWSERIFY_CMD) -e lib/babel/polyfill.js >dist/polyfill.js
 	node $(UGLIFY_CMD) dist/polyfill.js >dist/polyfill.min.js
 
-	node $(BROWSERIFY_CMD) lib/babel/api/browser.js -s babel >dist/babel.js
+	node $(BROWSERIFY_CMD) lib/babel/api/browser.js -s babel $(BROWSERIFY_IGNORE) >dist/browser.js
-	node $(UGLIFY_CMD) dist/babel.js >dist/babel.min.js
+	node $(UGLIFY_CMD) dist/browser.js >dist/browser.min.js
+
+	node $(BROWSERIFY_CMD) lib/babel/api/node.js --node $(BROWSERIFY_IGNORE) >dist/node.js
 
 	node packages/babel-cli/bin/babel-external-helpers >dist/external-helpers.js
 	node $(UGLIFY_CMD) dist/external-helpers.js >dist/external-helpers.min.js
@@ -61,7 +67,7 @@ test-cov:
 test-parser:
 	node test/acorn/run.js
 
-test-travis: bootstrap build test
+test-travis: bootstrap lint build test
 
 test-browser:
 	mkdir -p dist
@@ -73,7 +79,7 @@ test-browser:
 
 	test -n "`which open`" && open test/browser.html
 
-publish:
+publish: lint
 	git pull --rebase
 
 	make test
@@ -83,8 +89,8 @@ publish:
 
 	make build
 
-	cp dist/babel.js browser.js
+	cp dist/browser.js browser.js
-	cp dist/babel.min.js browser.min.js
+	cp dist/browser.min.js browser.min.js
 
 	cp dist/polyfill.js browser-polyfill.js
 	cp dist/polyfill.min.js browser-polyfill.min.js

README.md

@@ -9,7 +9,11 @@
 </p>
 
 <p align="center">
-  For questions and support please visit the <a href="https://gitter.im/babel/babel">gitter room</a> or <a href="http://stackoverflow.com/questions/tagged/babeljs">StackOverflow</a>. The Babel issue tracker is <strong>exclusively</strong> for bug reports and feature requests.
+  For questions and support please visit the <a href="https://babel-slack.herokuapp.com">slack channel</a> or <a href="http://stackoverflow.com/questions/tagged/babeljs">StackOverflow</a>. The Babel issue tracker is <strong>exclusively</strong> for bug reports and feature requests.
+</p>
+
+<p align="center">
+  Issues without instructions to reproduce <strong>will be immediately closed<strong>.
 </p>
 
 <p align="center">

doc/index.md

@@ -0,0 +1,4 @@
+This is a collection of documentation about babel internals, for use in development of babel.
+
+# [Properties of nodes](/doc/node-props.md)
+These are properties babel stores in AST node objects for internal use, as opposed to properties that are part of the AST spec (ESTree at the time of this writing).

doc/node-props.md

@@ -0,0 +1,11 @@
+# Properties of nodes
+These are properties babel stores in AST node objects for internal use, as opposed to properties that are part of the AST spec (ESTree at the time of this writing).
+
+## `_blockHoist`
+`node._blockHoist != null` triggers the [block-hoist transformer](/src/babel/transformation/transformers/internal/block-hoist.js). Value should be `true` or an integer in the range `0..3`. `true` is equivalent to `2`. The value indicates whether the node should be hoisted and to what degree. See the source code for more detailed information.
+
+## `_paths`
+Stores a representation of a node's position in the tree and relationship to other nodes.
+
+## `shadow`
+A truthy value on a function node triggers the [shadow-functions transformer](/src/babel/transformation/transformers/internal/shadow-functions.js), which transforms the node so that it references (or inherits) `arguments` and `this` from the parent scope. It is invoked for arrow functions, for example.

index.js

@@ -0,0 +1 @@
+module.exports = require("./lib/babel/api/node.js");

package.json

@@ -1,12 +1,11 @@
 {
   "name": "babel-core",
-  "description": "Turn ES6 code into readable vanilla ES5 with source maps",
+  "description": "A compiler for writing next generation JavaScript",
-  "version": "5.4.2",
+  "version": "5.6.12",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
   "repository": "babel/babel",
-  "main": "lib/babel/api/node.js",
   "browser": {
     "./lib/babel/api/register/node.js": "./lib/babel/api/register/browser.js"
   },
@@ -30,27 +29,41 @@
   "dependencies": {
     "acorn-jsx": "^1.0.0",
     "ast-types": "~0.7.0",
-    "bluebird": "^2.9.25",
+    "babel-plugin-constant-folding": "^1.0.1",
+    "babel-plugin-dead-code-elimination": "^1.0.2",
+    "babel-plugin-eval": "^1.0.1",
+    "babel-plugin-inline-environment-variables": "^1.0.1",
+    "babel-plugin-jscript": "^1.0.1",
+    "babel-plugin-member-expression-literals": "^1.0.1",
+    "babel-plugin-property-literals": "^1.0.1",
+    "babel-plugin-proto-to-assign": "^1.0.3",
+    "babel-plugin-react-constant-elements": "^1.0.3",
+    "babel-plugin-react-display-name": "^1.0.3",
+    "babel-plugin-remove-console": "^1.0.1",
+    "babel-plugin-remove-debugger": "^1.0.1",
+    "babel-plugin-runtime": "^1.0.7",
+    "babel-plugin-undeclared-variables-check": "^1.0.2",
+    "babel-plugin-undefined-to-void": "^1.1.6",
     "chalk": "^1.0.0",
     "convert-source-map": "^1.1.0",
     "core-js": "^0.9.0",
     "debug": "^2.1.1",
     "detect-indent": "^3.0.0",
-    "esquery": "^0.4.0",
     "estraverse": "^4.0.0",
     "esutils": "^2.0.0",
     "fs-readdir-recursive": "^0.1.0",
     "globals": "^6.4.0",
+    "home-or-tmp": "^1.0.0",
     "is-integer": "^1.0.4",
-    "js-tokens": "1.0.0",
+    "js-tokens": "1.0.1",
-    "leven": "^1.0.1",
     "line-numbers": "0.2.0",
     "lodash": "^3.6.0",
     "minimatch": "^2.0.3",
     "output-file-sync": "^1.1.0",
+    "path-exists": "^1.0.0",
     "path-is-absolute": "^1.0.0",
     "private": "^0.1.6",
-    "regenerator": "^0.8.20",
+    "regenerator": "0.8.31",
     "regexpu": "^1.1.2",
     "repeating": "^1.1.2",
     "resolve": "^1.1.6",
@@ -60,15 +73,14 @@
     "source-map-support": "^0.2.10",
     "strip-json-comments": "^1.0.2",
     "to-fast-properties": "^1.0.0",
-    "trim-right": "^1.0.0",
+    "trim-right": "^1.0.0"
-    "user-home": "^1.1.1"
   },
   "devDependencies": {
-    "babel": "5.3.1",
+    "babel": "5.6.10",
     "browserify": "^9.0.8",
     "chai": "^2.2.0",
-    "eslint": "^0.18.0",
+    "eslint": "^0.21.2",
-    "babel-eslint": "^2.0.0",
+    "babel-eslint": "^3.1.9",
     "esvalid": "^1.1.0",
     "istanbul": "^0.3.5",
     "matcha": "^0.6.0",

packages/babel-cli/bin/_babel-node

@@ -107,6 +107,7 @@ if (program.eval || program.print) {
 
     // add back on node and concat the sliced args
     process.argv = ["node"].concat(args);
+    process.execArgv.unshift(__filename);
 
     Module.runMain();
   } else {

packages/babel-cli/bin/babel-node

@@ -412,6 +412,7 @@ babelArgs.forEach(function(arg){
     case "--prof_auto":
     case "--prof_lazy":
     case "--sliding_state_window":
+    case "--nolazy":
       args.unshift(arg);
       break;
 

packages/babel-cli/bin/babel-plugin/index.js

@@ -0,0 +1,141 @@
+#!/usr/bin/env node
+
+var pathExists = require("path-exists");
+var readline   = require("readline");
+var child      = require("child_process");
+var path       = require("path");
+var fs         = require("fs");
+
+function spawn(cmd, args, callback) {
+  console.log(">", cmd, args);
+
+  var spawn = child.spawn(cmd, args, { stdio: "inherit" });
+
+  spawn.on("exit", function (code) {
+    if (code === 0) {
+      if (callback) callback();
+    } else {
+      console.log("Killing...");
+      process.exit(1);
+    }
+  });
+}
+
+function spawnMultiple(cmds) {
+  function next() {
+    var cmd = cmds.shift();
+    if (cmd) {
+      spawn(cmd.command, cmd.args, next);
+    } else {
+      process.exit();
+    }
+  }
+
+  next();
+}
+
+function template(name, data) {
+  var source = fs.readFileSync(path.join(__dirname, "templates", name), "utf8");
+  source = source.replace(/[A-Z_]+/g, function (key) {
+    return data[key] === undefined ? key : data[key];
+  });
+  return source;
+}
+
+function write(filename, content) {
+  console.log(filename);
+  fs.writeFileSync(filename, content);
+}
+
+var rl = readline.createInterface({
+  input: process.stdin,
+  output: process.stdout
+});
+
+var BABEL_PLUGIN_PREFIX = "babel-plugin-";
+
+var cmds = {
+  init: function () {
+    var name = path.basename(process.cwd());
+
+    if (name.indexOf(BABEL_PLUGIN_PREFIX) === 0) {
+      name = name.slice(BABEL_PLUGIN_PREFIX.length);
+    }
+
+    rl.question("Description (optional): ", function (description) {
+      rl.question("GitHub Repository (eg. sebmck/babel-plugin-foobar) (optional): ", function (repo) {
+        rl.close();
+
+        var templateData = {
+          DESCRIPTION: description,
+          FULL_NAME: BABEL_PLUGIN_PREFIX + name,
+          NAME: name
+        };
+
+        write("package.json", JSON.stringify({
+          name: templateData.FULL_NAME,
+          version: "1.0.0",
+          description: templateData.DESCRIPTION,
+          repository: repo || undefined,
+          license: "MIT",
+          main: "lib/index.js",
+
+          devDependencies: {
+            babel: "^5.6.0"
+          },
+
+          scripts: {
+            build: "babel-plugin build",
+            push:  "babel-plugin publish",
+            test:  "babel-plugin test"
+          },
+
+          keywords: ["babel-plugin"]
+        }, null, "  ") + "\n");
+
+        write(".npmignore", "node_modules\n*.log\nsrc\n");
+
+        write(".gitignore", "node_modules\n*.log\nlib\n");
+
+        write("README.md", template("README.md", templateData));
+
+        if (!pathExists.sync("src")) {
+          fs.mkdirSync("src");
+          write("src/index.js", template("index.js", templateData));
+        }
+      });
+    });
+  },
+
+  build: function () {
+    spawn("babel", ["src", "--out-dir", "lib", "--copy-files"]);
+  },
+
+  publish: function () {
+    var pkg = require(process.cwd() + "/package.json");
+    console.log("Current verison:", pkg.version);
+
+    rl.question("New version (enter nothing for patch): ", function (newVersion) {
+      rl.close();
+
+      newVersion = newVersion || "patch";
+
+      spawnMultiple([
+        { command: "git", args: ["pull"] },
+        { command: "git", args: ["push"] },
+        { command: "babel-plugin", args: ["build"] },
+        { command: "npm", args: ["version", newVersion] },
+        { command: "npm", args: ["publish"] },
+        { command: "git", args: ["push", "--follow-tags"] }
+      ]);
+    });
+  }
+};
+
+var cmd = cmds[process.argv[2]];
+if (cmd) {
+  cmd();
+} else {
+  console.error("Unknown command:", cmd);
+  process.exit(1);
+}

packages/babel-cli/bin/babel-plugin/templates/README.md

@@ -0,0 +1,35 @@
+# FULL_NAME
+
+DESCRIPTION
+
+## Installation
+
+```sh
+$ npm install FULL_NAME
+```
+
+## Usage
+
+### Via `.babelrc` (Recommended)
+
+**.babelrc**
+
+```json
+{
+  "plugins": ["NAME"]
+}
+```
+
+### Via CLI
+
+```sh
+$ babel --plugins NAME script.js
+```
+
+### Via Node API
+
+```javascript
+require("babel-core").transform("code", {
+  plugins: ["NAME"]
+});
+```

packages/babel-cli/bin/babel-plugin/templates/index.js

@@ -0,0 +1,7 @@
+export default function ({ Plugin, types: t }) {
+  return new Plugin("NAME", {
+    visitor: {
+      // your visitor methods go here
+    }
+  });
+}

packages/babel-cli/bin/babel/dir.js

@@ -1,4 +1,5 @@
 var outputFileSync = require("output-file-sync");
+var pathExists     = require("path-exists");
 var chokidar       = require("chokidar");
 var slash          = require("slash");
 var path           = require("path");
@@ -6,7 +7,7 @@ var util           = require("./util");
 var fs             = require("fs");
 var _              = require("lodash");
 
-module.exports = function (commander, filenames, opts) {
+module.exports = function (commander, filenames) {
   var write = function (src, relative) {
     // remove extension and then append back on .js
     relative = relative.replace(/\.(\w*?)$/, "") + ".js";
@@ -14,7 +15,8 @@ module.exports = function (commander, filenames, opts) {
     var dest = path.join(commander.outDir, relative);
 
     var data = util.compile(src, {
-      sourceFileName: slash(path.relative(dest + "/..", src))
+      sourceFileName: slash(path.relative(dest + "/..", src)),
+      sourceMapTarget: path.basename(relative)
     });
     if (data.ignored) return;
 
@@ -40,7 +42,7 @@ module.exports = function (commander, filenames, opts) {
   };
 
   var handle = function (filename) {
-    if (!fs.existsSync(filename)) return;
+    if (!pathExists.sync(filename)) return;
 
     var stat = fs.statSync(filename);
 

packages/babel-cli/bin/babel/file.js

@@ -1,4 +1,5 @@
 var convertSourceMap = require("convert-source-map");
+var pathExists       = require("path-exists");
 var sourceMap        = require("source-map");
 var chokidar         = require("chokidar");
 var slash            = require("slash");
@@ -16,7 +17,8 @@ module.exports = function (commander, filenames, opts) {
 
   var buildResult = function () {
     var map = new sourceMap.SourceMapGenerator({
-      file: slash(commander.outFile || "stdout")
+      file: path.basename(commander.outFile) || "stdout",
+      sourceRoot: opts.sourceRoot
     });
 
     var code = "";
@@ -99,7 +101,7 @@ module.exports = function (commander, filenames, opts) {
     results = [];
 
     _.each(filenames, function (filename) {
-      if (!fs.existsSync(filename)) return;
+      if (!pathExists.sync(filename)) return;
 
       var stat = fs.statSync(filename);
       if (stat.isDirectory()) {

packages/babel-cli/bin/babel/index.js

@@ -1,14 +1,17 @@
 #!/usr/bin/env node
 
+require("babel-core");
+
 var moduleFormatters = require("babel-core/lib/babel/transformation/modules");
+var pathExists       = require("path-exists");
 var commander        = require("commander");
 var transform        = require("babel-core").transform;
 var kebabCase        = require("lodash/string/kebabCase");
 var options          = require("babel-core").options;
 var util             = require("babel-core").util;
+var uniq             = require("lodash/array/uniq");
 var each             = require("lodash/collection/each");
 var keys             = require("lodash/object/keys");
-var fs               = require("fs");
 var glob             = require("glob");
 
 each(options, function (option, key) {
@@ -35,7 +38,7 @@ each(options, function (option, key) {
   if (option.description) desc.push(option.description);
 
   commander.option(arg, desc.join(" "));
-})
+});
 
 commander.option("-x, --extensions [extensions]", "List of extensions to compile when a directory has been input [.es6,.js,.es,.jsx]");
 commander.option("-w, --watch", "Recompile files on changes");
@@ -51,7 +54,7 @@ commander.on("--help", function () {
     each(keys(obj).sort(), function (key) {
       if (key[0] === "_") return;
 
-      if (obj[key].optional) key = "[" + key + "]";
+      if (obj[key].metadata && obj[key].metadata.optional) key = "[" + key + "]";
 
       console.log("    - " + key);
     });
@@ -79,11 +82,15 @@ if (commander.extensions) {
 var errors = [];
 
 var filenames = commander.args.reduce(function (globbed, input) {
-  return globbed.concat(glob.sync(input));
+  var files = glob.sync(input);
+  if (!files.length) files = [input];
+  return globbed.concat(files);
 }, []);
 
+filenames = uniq(filenames);
+
 each(filenames, function (filename) {
-  if (!fs.existsSync(filename)) {
+  if (!pathExists.sync(filename)) {
     errors.push(filename + " doesn't exist");
   }
 });
@@ -116,11 +123,16 @@ if (errors.length) {
 var opts = exports.opts = {};
 
 each(options, function (opt, key) {
-  opts[key] = commander[key];
+  if (commander[key] !== undefined) {
+    opts[key] = commander[key];
+  }
 });
 
 opts.ignore = util.arrayify(opts.ignore, util.regexify);
-opts.only   = util.arrayify(opts.only, util.regexify);
+
+if (opts.only) {
+  opts.only = util.arrayify(opts.only, util.regexify);
+}
 
 var fn;
 

packages/babel-cli/bin/babel/util.js

@@ -1,10 +1,11 @@
-var readdir = require("fs-readdir-recursive");
+var commander = require("commander");
-var index   = require("./index");
+var readdir   = require("fs-readdir-recursive");
-var babel   = require("babel-core");
+var index     = require("./index");
-var util    = require("babel-core").util;
+var babel     = require("babel-core");
-var path    = require("path");
+var util      = require("babel-core").util;
-var fs      = require("fs");
+var path      = require("path");
-var _       = require("lodash");
+var fs        = require("fs");
+var _         = require("lodash");
 
 exports.readdirFilter = function (filename) {
   return readdir(filename).filter(function (filename) {
@@ -37,6 +38,15 @@ exports.transform = function (filename, code, opts) {
 };
 
 exports.compile = function (filename, opts) {
-  var code = fs.readFileSync(filename, "utf8");
+  try {
-  return exports.transform(filename, code, opts);
+    var code = fs.readFileSync(filename, "utf8");
+    return exports.transform(filename, code, opts);
+  } catch (err) {
+    if (commander.watch) {
+      console.error(err.stack);
+      return { ignored: true };
+    } else {
+      throw err;
+    }
+  }
 };

packages/babel-cli/package.json

@@ -1,14 +1,14 @@
 {
   "name": "babel",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "5.4.1",
+  "version": "5.6.11",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://babeljs.io/",
   "license": "MIT",
   "repository": "babel/babel",
   "preferGlobal": true,
   "dependencies": {
-    "babel-core": "^5.4.1",
+    "babel-core": "^5.6.11",
     "chokidar": "^1.0.0",
     "commander": "^2.6.0",
     "convert-source-map": "^1.1.0",
@@ -16,6 +16,7 @@
     "glob": "^5.0.5",
     "lodash": "^3.2.0",
     "output-file-sync": "^1.1.0",
+    "path-exists": "^1.0.0",
     "path-is-absolute": "^1.0.0",
     "source-map": "^0.4.0",
     "slash": "^1.0.0"
@@ -23,6 +24,7 @@
   "bin": {
     "babel": "./bin/babel/index.js",
     "babel-node": "./bin/babel-node",
-    "babel-external-helpers": "./bin/babel-external-helpers"
+    "babel-external-helpers": "./bin/babel-external-helpers",
+    "babel-plugin": "./bin/babel-plugin/index.js"
   }
 }

packages/babel-runtime/package.json

@@ -1,7 +1,7 @@
 {
   "name": "babel-runtime",
   "description": "babel selfContained runtime",
-  "version": "5.4.1",
+  "version": "5.6.11",
   "license": "MIT",
   "repository": "babel/babel",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",

packages/build-runtime.js

@@ -75,7 +75,7 @@ writeFile("regenerator/runtime.js", selfContainify(readFile("regenerator/runtime
 
 //
 
-var coreDefinitions = require("../lib/babel/transformation/transformers/other/runtime/definitions");
+var coreDefinitions = require("babel-plugin-runtime/lib/definitions");
 
 var paths = ["is-iterable", "get-iterator"];
 

src/acorn/plugins/flow.js

@@ -1,3 +1,4 @@
+Error.stackTraceLimit = Infinity;
 var acorn = require("../src/index")
 
 var pp = acorn.Parser.prototype
@@ -41,8 +42,11 @@ pp.flow_parseDeclareFunction = function (node) {
   typeNode.rest = tmp.rest
   this.expect(tt.parenR)
 
+  var oldInType = this.inType
+  this.inType = true
   this.expect(tt.colon)
   typeNode.returnType = this.flow_parseType()
+  this.inType = oldInType
 
   typeContainer.typeAnnotation = this.finishNode(typeNode, "FunctionTypeAnnotation")
   id.typeAnnotation = this.finishNode(typeContainer, "TypeAnnotation")
@@ -352,12 +356,6 @@ pp.flow_parseGenericType = function (start, id) {
   return this.finishNode(node, "GenericTypeAnnotation")
 }
 
-pp.flow_parseVoidType = function () {
-  var node = this.startNode()
-  this.expect(tt._void)
-  return this.finishNode(node, "VoidTypeAnnotation")
-}
-
 pp.flow_parseTypeofType = function () {
   var node = this.startNode()
   this.expect(tt._typeof)
@@ -411,10 +409,16 @@ pp.flow_identToTypeAnnotation = function (start, node, id) {
     case "any":
       return this.finishNode(node, "AnyTypeAnnotation")
 
+    case "void":
+      return this.finishNode(node, "VoidTypeAnnotation")
+
     case "bool":
     case "boolean":
       return this.finishNode(node, "BooleanTypeAnnotation")
 
+    case "mixed":
+      return this.finishNode(node, "MixedTypeAnnotation")
+
     case "number":
       return this.finishNode(node, "NumberTypeAnnotation")
 
@@ -521,14 +525,8 @@ pp.flow_parsePrimaryType = function () {
       return this.finishNode(node, "StringLiteralTypeAnnotation")
 
     default:
-      if (this.type.keyword) {
+      if (this.type.keyword === "typeof") {
-        switch (this.type.keyword) {
+        return this.flow_parseTypeofType()
-          case "void":
-            return this.flow_parseVoidType()
-
-          case "typeof":
-            return this.flow_parseTypeofType()
-        }
       }
   }
 
@@ -691,6 +689,18 @@ acorn.plugins.flow = function (instance) {
     }
   })
 
+  // don't consider `void` to be a keyword as then it'll use the void token type
+  // and set startExpr
+  instance.extend("isKeyword", function (inner) {
+    return function(name) {
+      if (this.inType && name === "void") {
+        return false
+      } else {
+        return inner.call(this, name)
+      }
+    }
+  })
+
   instance.extend("readToken", function (inner) {
     return function(code) {
       if (this.inType && (code === 62 || code === 60)) {

src/acorn/src/expression.js

@@ -29,14 +29,23 @@ const pp = Parser.prototype
 // strict mode, init properties are also not allowed to be repeated.
 
 pp.checkPropClash = function(prop, propHash) {
-  if (this.options.ecmaVersion >= 6) return
+  if (this.options.ecmaVersion >= 6 && (prop.computed || prop.method || prop.shorthand))
+    return
   let key = prop.key, name
   switch (key.type) {
   case "Identifier": name = key.name; break
   case "Literal": name = String(key.value); break
   default: return
   }
-  let kind = prop.kind || "init", other
+  let kind = prop.kind
+  if (this.options.ecmaVersion >= 6) {
+    if (name === "__proto__" && kind === "init") {
+      if (propHash.proto) this.raise(key.start, "Redefinition of __proto__ property");
+      propHash.proto = true
+    }
+    return
+  }
+  let other
   if (has(propHash, name)) {
     other = propHash[name]
     let isGetSet = kind !== "init"
@@ -260,8 +269,10 @@ pp.parseNoCallExpr = function() {
 pp.parseExprAtom = function(refShorthandDefaultPos) {
   let node, canBeArrow = this.potentialArrowAt == this.start
   switch (this.type) {
-  case tt._this:
   case tt._super:
+    if (!this.inFunction)
+      this.raise(this.start, "'super' outside of function or class")
+  case tt._this:
     let type = this.type === tt._this ? "ThisExpression" : "Super"
     node = this.startNode()
     this.next()
@@ -274,7 +285,13 @@ pp.parseExprAtom = function(refShorthandDefaultPos) {
     if (this.options.features["es7.doExpressions"]) {
       let node = this.startNode()
       this.next()
+      var oldInFunction = this.inFunction
+      var oldLabels = this.labels
+      this.labels = []
+      this.inFunction = false
       node.body = this.parseBlock()
+      this.inFunction = oldInFunction
+      this.labels = oldLabels
       return this.finishNode(node, "DoExpression")
     }
 
@@ -286,7 +303,7 @@ pp.parseExprAtom = function(refShorthandDefaultPos) {
     //
     if (this.options.features["es7.asyncFunctions"]) {
       // async functions!
-      if (id.name === "async") {
+      if (id.name === "async" && !this.canInsertSemicolon()) {
         // arrow functions
         if (this.type === tt.parenL) {
           let expr = this.parseParenAndDistinguishExpression(start, true, true)
@@ -415,9 +432,18 @@ pp.parseParenAndDistinguishExpression = function(start, isAsync, canBeArrow) {
     }
 
     let innerStart = this.markPosition(), exprList = [], first = true
-    let refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart
+    let refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart, optionalCommaStart
     while (this.type !== tt.parenR) {
-      first ? first = false : this.expect(tt.comma)
+      if (first) {
+        first = false;
+      } else {
+        this.expect(tt.comma)
+        if (this.type === tt.parenR && this.options.features["es7.trailingFunctionCommas"]) {
+          optionalCommaStart = this.start
+          break
+        }
+      }
+
       if (this.type === tt.ellipsis) {
         let spreadNodeStart = this.markPosition()
         spreadStart = this.start
@@ -445,6 +471,7 @@ pp.parseParenAndDistinguishExpression = function(start, isAsync, canBeArrow) {
         this.unexpected(this.lastTokStart)
       }
     }
+    if (optionalCommaStart) this.unexpected(optionalCommaStart)
     if (spreadStart) this.unexpected(spreadStart)
     if (refShorthandDefaultPos.start) this.unexpected(refShorthandDefaultPos.start)
 
@@ -507,7 +534,7 @@ pp.parseNew = function() {
 pp.parseTemplateElement = function() {
   let elem = this.startNode()
   elem.value = {
-    raw: this.input.slice(this.start, this.end),
+    raw: this.input.slice(this.start, this.end).replace(/\r\n?/g, '\n'),
     cooked: this.value
   }
   this.next()
@@ -603,6 +630,14 @@ pp.parseObjPropValue = function (prop, start, isGenerator, isAsync, isPattern, r
     prop.kind = prop.key.name
     this.parsePropertyName(prop)
     prop.value = this.parseMethod(false)
+    let paramCount = prop.kind === "get" ? 0 : 1
+    if (prop.value.params.length !== paramCount) {
+      let start = prop.value.start
+      if (prop.kind === "get")
+        this.raise(start, "getter should have no params");
+      else
+        this.raise(start, "setter should have exactly one param")
+    }
   } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") {
     prop.kind = "init"
     if (isPattern) {
@@ -628,12 +663,12 @@ pp.parsePropertyName = function(prop) {
       prop.computed = true
       prop.key = this.parseMaybeAssign()
       this.expect(tt.bracketR)
-      return
+      return prop.key
     } else {
       prop.computed = false
     }
   }
-  prop.key = (this.type === tt.num || this.type === tt.string) ? this.parseExprAtom() : this.parseIdent(true)
+  return prop.key = (this.type === tt.num || this.type === tt.string) ? this.parseExprAtom() : this.parseIdent(true)
 }
 
 // Initialize empty function node.

src/acorn/src/lookahead.js

@@ -9,6 +9,7 @@ var STATE_KEYS = [
   "lastTokEnd",
   "lineStart",
   "startLoc",
+  "curLine",
   "endLoc",
   "start",
   "pos",
@@ -18,7 +19,11 @@ var STATE_KEYS = [
   "exprAllowed",
   "potentialArrowAt",
   "currLine",
-  "input"
+  "input",
+  "inType",
+  "inFunction",
+  "inGenerator",
+  "labels"
 ];
 
 pp.getState = function () {
@@ -28,6 +33,7 @@ pp.getState = function () {
     state[key] = this[key]
   }
   state.context = this.context.slice()
+  state.labels = this.labels.slice()
   return state
 };
 

src/acorn/src/lval.js

@@ -35,6 +35,7 @@ pp.toAssignable = function(node, isBinding) {
     case "AssignmentExpression":
       if (node.operator === "=") {
         node.type = "AssignmentPattern"
+        delete node.operator
       } else {
         this.raise(node.left.end, "Only '=' operator can be used for specifying default value.")
       }
@@ -171,7 +172,7 @@ pp.checkLVal = function(expr, isBinding, checkClashes) {
     break
 
   case "ObjectPattern":
-    for (let i = 0; i < expr.properties.length; i++) {
+       for (let i = 0; i < expr.properties.length; i++) {
       var prop = expr.properties[i];
       if (prop.type === "Property") prop = prop.value;
       this.checkLVal(prop, isBinding, checkClashes)
@@ -194,6 +195,10 @@ pp.checkLVal = function(expr, isBinding, checkClashes) {
     this.checkLVal(expr.argument, isBinding, checkClashes)
     break
 
+  case "ParenthesizedExpression":
+    this.checkLVal(expr.expression, isBinding, checkClashes)
+    break
+
   default:
     this.raise(expr.start, (isBinding ? "Binding" : "Assigning to") + " rvalue")
   }

src/acorn/src/state.js

@@ -1,13 +1,14 @@
 import {reservedWords, keywords} from "./identifier"
-import {types as tt, lineBreak} from "./tokentype"
+import {types as tt} from "./tokentype"
+import {lineBreak} from "./whitespace"
 
 export function Parser(options, input, startPos) {
   this.options = options
-  this.loadPlugins(this.options.plugins)
   this.sourceFile = this.options.sourceFile || null
   this.isKeyword = keywords[this.options.ecmaVersion >= 6 ? 6 : 5]
   this.isReservedWord = reservedWords[this.options.ecmaVersion]
   this.input = input
+  this.loadPlugins(this.options.plugins)
 
   // Set up token state
 

src/acorn/src/statement.js

@@ -83,10 +83,13 @@ pp.parseStatement = function(declaration, topLevel) {
     return starttype === tt._import ? this.parseImport(node) : this.parseExport(node)
 
   case tt.name:
-    if (this.options.features["es7.asyncFunctions"] && this.value === "async" && this.lookahead().type === tt._function) {
+    if (this.options.features["es7.asyncFunctions"] && this.value === "async") {
-      this.next();
+      var lookahead = this.lookahead();
-      this.expect(tt._function);
+      if (lookahead.type === tt._function && !this.canInsertSemicolon.call(lookahead)) {
-      return this.parseFunction(node, true, false, true);
+        this.next();
+        this.expect(tt._function);
+        return this.parseFunction(node, true, false, true);
+      }
     }
 
     // If the statement does not start with a statement keyword or a
@@ -168,12 +171,6 @@ pp.parseDoStatement = function(node) {
   this.labels.push(loopLabel)
   node.body = this.parseStatement(false)
   this.labels.pop()
-  if (this.options.features["es7.doExpressions"] && this.type !== tt._while) {
-    let container = this.startNodeAt(start)
-    container.expression = this.finishNode(node, "DoExpression")
-    this.semicolon()
-    return this.finishNode(container, "ExpressionStatement")
-  }
   this.expect(tt._while)
   node.test = this.parseParenExpression()
   if (this.options.ecmaVersion >= 6)
@@ -350,7 +347,14 @@ pp.parseLabeledStatement = function(node, maybeName, expr) {
   for (let i = 0; i < this.labels.length; ++i)
     if (this.labels[i].name === maybeName) this.raise(expr.start, "Label '" + maybeName + "' is already declared")
   let kind = this.type.isLoop ? "loop" : this.type === tt._switch ? "switch" : null
-  this.labels.push({name: maybeName, kind: kind})
+  for (let i = this.labels.length - 1; i >= 0; i--) {
+    let label = this.labels[i]
+    if (label.statementStart == node.start) {
+      label.statementStart = this.start;
+      label.kind = kind;
+    } else break;
+  }
+  this.labels.push({name: maybeName, kind: kind, statementStart: this.start})
   node.body = this.parseStatement(true)
   this.labels.pop()
   node.label = expr
@@ -469,6 +473,7 @@ pp.parseClass = function(node, isStatement) {
   this.parseClassId(node, isStatement)
   this.parseClassSuper(node)
   var classBody = this.startNode()
+  let hadConstructor = false
   classBody.body = []
   this.expect(tt.braceL)
   let decorators = []
@@ -483,16 +488,14 @@ pp.parseClass = function(node, isStatement) {
       method.decorators = decorators
       decorators = []
     }
+    let isMaybeStatic = this.type === tt.name && this.value === "static"
     var isGenerator = this.eat(tt.star), isAsync = false
     this.parsePropertyName(method)
-    if (this.type !== tt.parenL && !method.computed && method.key.type === "Identifier" &&
+    method.static = isMaybeStatic && this.type !== tt.parenL
-        method.key.name === "static") {
+    if (method.static) {
       if (isGenerator) this.unexpected()
-      method['static'] = true
       isGenerator = this.eat(tt.star)
       this.parsePropertyName(method)
-    } else {
-      method['static'] = false
     }
     if (!isGenerator && method.key.type === "Identifier" && !method.computed && this.isClassProperty()) {
       classBody.body.push(this.parseClassProperty(method))
@@ -503,23 +506,39 @@ pp.parseClass = function(node, isStatement) {
       isAsync = true
       this.parsePropertyName(method)
     }
+    let isGetSet = false
     method.kind = "method"
-    if (!method.computed && !isGenerator && !isAsync) {
+    if (!method.computed) {
-      if (method.key.type === "Identifier") {
+      let {key} = method
-        if (this.type !== tt.parenL && (method.key.name === "get" || method.key.name === "set")) {
+      if (!isAsync && !isGenerator && key.type === "Identifier" && this.type !== tt.parenL && (key.name === "get" || key.name === "set")) {
-          method.kind = method.key.name
+        isGetSet = true
-          this.parsePropertyName(method)
+        method.kind = key.name
-        } else if (!method['static'] && method.key.name === "constructor") {
+        key = this.parsePropertyName(method)
-          method.kind = "constructor"
+      }
-        }
+      if (!method.static && (key.type === "Identifier" && key.name === "constructor" ||
-      } else if (!method['static'] && method.key.type === "Literal" && method.key.value === "constructor") {
+          key.type === "Literal" && key.value === "constructor")) {
+        if (hadConstructor) this.raise(key.start, "Duplicate constructor in the same class")
+        if (isGetSet) this.raise(key.start, "Constructor can't have get/set modifier")
+        if (isGenerator) this.raise(key.start, "Constructor can't be a generator")
+        if (isAsync) this.raise(key.start, "Constructor can't be an async function")
         method.kind = "constructor"
+        hadConstructor = true
       }
     }
     if (method.kind === "constructor" && method.decorators) {
       this.raise(method.start, "You can't attach decorators to a class constructor")
     }
     this.parseClassMethod(classBody, method, isGenerator, isAsync)
+    if (isGetSet) {
+      let paramCount = method.kind === "get" ? 0 : 1
+      if (method.value.params.length !== paramCount) {
+        let start = method.value.start
+        if (method.kind === "get")
+          this.raise(start, "getter should have no params");
+        else
+          this.raise(start, "setter should have exactly one param")
+      }
+    }
   }
   if (decorators.length) {
     this.raise(this.start, "You have trailing decorators with no method");
@@ -574,7 +593,7 @@ pp.parseExport = function(node) {
       this.parseExportFrom(node)
       return this.finishNode(node, "ExportAllDeclaration")
     }
-  } else if (this.isExportDefaultSpecifier()) {
+  } else if (this.options.features["es7.exportExtensions"] && this.isExportDefaultSpecifier()) {
     let specifier = this.startNode()
     specifier.exported = this.parseIdent(true)
     node.specifiers = [this.finishNode(specifier, "ExportDefaultSpecifier")]

src/acorn/src/tokenize.js

@@ -25,6 +25,9 @@ export class Token {
 
 const pp = Parser.prototype
 
+// Are we running under Rhino?
+const isRhino = typeof Packages == "object" && Object.prototype.toString.call(Packages) == "[object JavaPackage]"
+
 // Move to the next token
 
 pp.next = function() {
@@ -430,23 +433,30 @@ pp.readRegexp = function() {
       // negatives in unlikely scenarios. For example, `[\u{61}-b]` is a
       // perfectly valid pattern that is equivalent to `[a-b]`, but it would
       // be replaced by `[x-b]` which throws an error.
-      tmp = tmp.replace(/\\u([a-fA-F0-9]{4})|\\u\{([0-9a-fA-F]+)\}|[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "x")
+      tmp = tmp.replace(/\\u\{([0-9a-fA-F]+)\}/g, (match, code, offset) => {
+        code = Number("0x" + code)
+        if (code > 0x10FFFF) this.raise(start + offset + 3, "Code point out of bounds")
+        return "x"
+      });
+      tmp = tmp.replace(/\\u([a-fA-F0-9]{4})|[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "x")
     }
   }
   // Detect invalid regular expressions.
-  try {
+  let value = null
-    new RegExp(tmp)
+  // Rhino's regular expression parser is flaky and throws uncatchable exceptions,
-  } catch (e) {
+  // so don't do detection if we are running under Rhino
-    if (e instanceof SyntaxError) this.raise(start, "Error parsing regular expression: " + e.message)
+  if (!isRhino) {
-    this.raise(e)
+    try {
-  }
+      new RegExp(tmp)
-  // Get a regular expression object for this pattern-flag pair, or `null` in
+    } catch (e) {
-  // case the current environment doesn't support the flags it uses.
+      if (e instanceof SyntaxError) this.raise(start, "Error parsing regular expression: " + e.message)
-  let value
+      this.raise(e)
-  try {
+    }
-    value = new RegExp(content, mods)
+    // Get a regular expression object for this pattern-flag pair, or `null` in
-  } catch (err) {
+    // case the current environment doesn't support the flags it uses.
-    value = null
+    try {
+      value = new RegExp(content, mods)
+    } catch (err) {}
   }
   return this.finishToken(tt.regexp, {pattern: content, flags: mods, value: value})
 }
@@ -514,10 +524,10 @@ pp.readCodePoint = function() {
 
   if (ch === 123) {
     if (this.options.ecmaVersion < 6) this.unexpected()
-    ++this.pos
+    let codePos = ++this.pos
     code = this.readHexChar(this.input.indexOf('}', this.pos) - this.pos)
     ++this.pos
-    if (code > 0x10FFFF) this.unexpected()
+    if (code > 0x10FFFF) this.raise(codePos, "Code point out of bounds")
   } else {
     code = this.readHexChar(4)
   }
@@ -539,7 +549,7 @@ pp.readString = function(quote) {
     if (ch === quote) break
     if (ch === 92) { // '\'
       out += this.input.slice(chunkStart, this.pos)
-      out += this.readEscapedChar()
+      out += this.readEscapedChar(false)
       chunkStart = this.pos
     } else {
       if (isNewLine(ch)) this.raise(this.start, "Unterminated string constant")
@@ -572,16 +582,20 @@ pp.readTmplToken = function() {
     }
     if (ch === 92) { // '\'
       out += this.input.slice(chunkStart, this.pos)
-      out += this.readEscapedChar()
+      out += this.readEscapedChar(true)
       chunkStart = this.pos
     } else if (isNewLine(ch)) {
       out += this.input.slice(chunkStart, this.pos)
       ++this.pos
-      if (ch === 13 && this.input.charCodeAt(this.pos) === 10) {
+      switch (ch) {
-        ++this.pos
+        case 13:
-        out += "\n"
+          if (this.input.charCodeAt(this.pos) === 10) ++this.pos;
-      } else {
+        case 10:
-        out += String.fromCharCode(ch)
+          out += "\n";
+          break;
+        default:
+          out += String.fromCharCode(ch);
+          break;
       }
       if (this.options.locations) {
         ++this.curLine
@@ -596,42 +610,46 @@ pp.readTmplToken = function() {
 
 // Used to read escaped characters
 
-pp.readEscapedChar = function() {
+pp.readEscapedChar = function(inTemplate) {
   let ch = this.input.charCodeAt(++this.pos)
-  let octal = /^[0-7]+/.exec(this.input.slice(this.pos, this.pos + 3))
-  if (octal) octal = octal[0]
-  while (octal && parseInt(octal, 8) > 255) octal = octal.slice(0, -1)
-  if (octal === "0") octal = null
   ++this.pos
-  if (octal) {
+  switch (ch) {
-    if (this.strict) this.raise(this.pos - 2, "Octal literal in strict mode")
+  case 110: return "\n"; // 'n' -> '\n'
-    this.pos += octal.length - 1
+  case 114: return "\r"; // 'r' -> '\r'
-    return String.fromCharCode(parseInt(octal, 8))
+  case 120: return String.fromCharCode(this.readHexChar(2)); // 'x'
-  } else {
+  case 117: return codePointToString(this.readCodePoint()); // 'u'
-    switch (ch) {
+  case 116: return "\t"; // 't' -> '\t'
-    case 110: return "\n"; // 'n' -> '\n'
+  case 98: return "\b"; // 'b' -> '\b'
-    case 114: return "\r"; // 'r' -> '\r'
+  case 118: return "\u000b"; // 'v' -> '\u000b'
-    case 120: return String.fromCharCode(this.readHexChar(2)); // 'x'
+  case 102: return "\f"; // 'f' -> '\f'
-    case 117: return codePointToString(this.readCodePoint()); // 'u'
+  case 13: if (this.input.charCodeAt(this.pos) === 10) ++this.pos; // '\r\n'
-    case 116: return "\t"; // 't' -> '\t'
+  case 10: // ' \n'
-    case 98: return "\b"; // 'b' -> '\b'
+    if (this.options.locations) { this.lineStart = this.pos; ++this.curLine }
-    case 118: return "\u000b"; // 'v' -> '\u000b'
+    return ""
-    case 102: return "\f"; // 'f' -> '\f'
+  default:
-    case 48: return "\0"; // 0 -> '\0'
+    if (ch >= 48 && ch <= 55) {
-    case 13: if (this.input.charCodeAt(this.pos) === 10) ++this.pos; // '\r\n'
+      let octalStr = this.input.substr(this.pos - 1, 3).match(/^[0-7]+/)[0]
-    case 10: // ' \n'
+      let octal = parseInt(octalStr, 8)
-      if (this.options.locations) { this.lineStart = this.pos; ++this.curLine }
+      if (octal > 255) {
-      return ""
+        octalStr = octalStr.slice(0, -1)
-    default: return String.fromCharCode(ch)
+        octal = parseInt(octalStr, 8)
+      }
+      if (octal > 0 && (this.strict || inTemplate)) {
+        this.raise(this.pos - 2, "Octal literal in strict mode")
+      }
+      this.pos += octalStr.length - 1
+      return String.fromCharCode(octal)
     }
+    return String.fromCharCode(ch)
   }
 }
 
 // Used to read character escape sequences ('\x', '\u', '\U').
 
 pp.readHexChar = function(len) {
+  let codePos = this.pos
   let n = this.readInt(16, len)
-  if (n === null) this.raise(this.start, "Bad character escape sequence")
+  if (n === null) this.raise(codePos, "Bad character escape sequence")
   return n
 }
 

src/acorn/src/tokentype.js

@@ -112,7 +112,7 @@ kw("case", beforeExpr)
 kw("catch")
 kw("continue")
 kw("debugger")
-kw("default")
+kw("default", beforeExpr)
 kw("do", {isLoop: true})
 kw("else", beforeExpr)
 kw("finally")

src/babel/api/browser.js

@@ -1,3 +1,5 @@
+/* eslint no-new-func: 0 */
+
 require("./node");
 var transform = module.exports = require("../transformation");
 

src/babel/api/node.js

@@ -8,9 +8,10 @@ export { util, acorn, transform };
 export { pipeline } from "../transformation";
 export { canCompile } from "../util";
 
-export { default as options } from "../transformation/file/options";
+export { default as options } from "../transformation/file/options/config";
+export { default as Plugin } from "../transformation/plugin";
 export { default as Transformer } from "../transformation/transformer";
-export { default as TransformerPipeline } from "../transformation/transformer-pipeline";
+export { default as Pipeline } from "../transformation/pipeline";
 export { default as traverse } from "../traversal";
 export { default as buildExternalHelpers } from "../tools/build-external-helpers";
 export { version } from "../../../package";
@@ -61,8 +62,8 @@ export function parse(code, opts = {}) {
   opts.sourceType = "module";
   opts.ecmaVersion = Infinity;
   opts.plugins = {
-    flow: true,
+    jsx:  true,
-    jsx:  true
+    flow: true
   };
   opts.features = {};
 

src/babel/api/register/browser.js

@@ -1,5 +1,5 @@
 // required to safely use babel/register within a browserify codebase
 
-export default function () {};
+export default function () {}
 
 import "../../polyfill";

src/babel/api/register/cache.js

@@ -1,9 +1,9 @@
 import path from "path";
-import os from "os";
 import fs from "fs";
-import userHome from "user-home";
+import homeOrTmp from "home-or-tmp";
+import pathExists from "path-exists";
 
-const FILENAME = process.env.BABEL_CACHE_PATH || path.join(userHome || os.tmpdir(), ".babel.json");
+const FILENAME = process.env.BABEL_CACHE_PATH || path.join(homeOrTmp, ".babel.json");
 var data = {};
 
 export function save() {
@@ -16,7 +16,7 @@ export function load() {
   process.on("exit", save);
   process.nextTick(save);
 
-  if (!fs.existsSync(FILENAME)) return;
+  if (!pathExists.sync(FILENAME)) return;
 
   try {
     data = JSON.parse(fs.readFileSync(FILENAME));

src/babel/api/register/node.js

@@ -1,12 +1,12 @@
 import sourceMapSupport from "source-map-support";
 import * as registerCache from "./cache";
-import resolveRc from "../../tools/resolve-rc";
+import resolveRc from "../../transformation/file/options/resolve-rc";
 import extend from "lodash/object/extend";
 import * as babel from "../node";
 import each from "lodash/collection/each";
 import * as util from  "../../util";
 import fs from "fs";
-import slash from "slash";
+import path from "path";
 
 sourceMapSupport.install({
   handleUncaughtExceptions: false,
@@ -38,14 +38,20 @@ var only;
 var oldHandlers   = {};
 var maps          = {};
 
+var cwd = process.cwd();
+
+var getRelativePath = function (filename){
+  return path.relative(cwd, filename);
+};
+
 var mtime = function (filename) {
   return +fs.statSync(filename).mtime;
 };
 
-var compile = function (filename) {
+var compile = function (filename, opts = {}) {
   var result;
 
-  var opts = extend({}, transformOpts);
+  opts = extend(opts, transformOpts);
 
   // this will be done when the file is transformed anyway but we need all
   // the options so we can generate the cache key
@@ -53,6 +59,9 @@ var compile = function (filename) {
 
   var cacheKey = `${filename}:${JSON.stringify(opts)}:${babel.version}`;
 
+  var env = process.env.BABEL_ENV || process.env.NODE_ENV;
+  if (env) cacheKey += `:${env}`;
+
   if (cache) {
     var cached = cache[cacheKey];
     if (cached && cached.mtime === mtime(filename)) {
@@ -79,9 +88,9 @@ var compile = function (filename) {
 
 var shouldIgnore = function (filename) {
   if (!ignore && !only) {
-    return /node_modules/.test(filename);
+    return getRelativePath(filename).split(path.sep).indexOf("node_modules") >= 0;
   } else {
-    return util.shouldIgnore(filename, ignore || [], only || []);
+    return util.shouldIgnore(filename, ignore || [], only);
   }
 };
 
@@ -95,7 +104,9 @@ if (process.env.running_under_istanbul) {
   fs.readFileSync = function (filename) {
     if (istanbulMonkey[filename]) {
       delete istanbulMonkey[filename];
-      var code = compile(filename);
+      var code = compile(filename, {
+        auxiliaryCommentBefore: "istanbul ignore next"
+      });
       istanbulMonkey[filename] = true;
       return code;
     } else {
@@ -114,7 +125,7 @@ var normalLoader = function (m, filename) {
 };
 
 var registerExtension = function (ext) {
-  var old = oldHandlers[ext] || oldHandlers[".js"];
+  var old = oldHandlers[ext] || oldHandlers[".js"] || require.extensions[".js"];
 
   var loader = normalLoader;
   if (process.env.running_under_istanbul) loader = istanbulLoader;
@@ -161,4 +172,4 @@ export default function (opts = {}) {
   delete opts.only;
 
   extend(transformOpts, opts);
-};
+}

src/babel/generation/buffer.js

@@ -54,9 +54,10 @@ export default class Buffer {
     this.space();
   }
 
-  space() {
+  space(force?) {
-    if (this.format.compact) return;
+    if (!force && this.format.compact) return;
-    if (this.buf && !this.isLast(" ") && !this.isLast("\n")) {
+
+    if (force || this.buf && !this.isLast(" ") && !this.isLast("\n")) {
       this.push(" ");
     }
   }
@@ -117,8 +118,9 @@ export default class Buffer {
 
   _removeSpacesAfterLastNewline() {
     var lastNewlineIndex = this.buf.lastIndexOf("\n");
-    if (lastNewlineIndex === -1)
+    if (lastNewlineIndex === -1) {
       return;
+    }
 
     var index = this.buf.length - 1;
     while (index > lastNewlineIndex) {
@@ -154,8 +156,12 @@ export default class Buffer {
     this.buf += str;
   }
 
-  endsWith(str) {
+  endsWith(str, buf = this.buf) {
-    return this.buf.slice(-str.length) === str;
+    if (str.length === 1) {
+      return buf[buf.length - 1] === str;
+    } else {
+      return buf.slice(-str.length) === str;
+    }
   }
 
   isLast(cha) {

src/babel/generation/generators/base.js

@@ -1,5 +1,5 @@
 export function File(node, print) {
-  print(node.program);
+  print.plain(node.program);
 }
 
 export function Program(node, print) {
@@ -17,3 +17,7 @@ export function BlockStatement(node, print) {
     this.rightBrace();
   }
 }
+
+export function Noop() {
+
+}

src/babel/generation/generators/classes.js

@@ -1,18 +1,18 @@
 export function ClassDeclaration(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
   this.push("class");
 
   if (node.id) {
-    this.space();
+    this.push(" ");
-    print(node.id);
+    print.plain(node.id);
   }
 
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
 
   if (node.superClass) {
     this.push(" extends ");
-    print(node.superClass);
+    print.plain(node.superClass);
-    print(node.superTypeParameters);
+    print.plain(node.superTypeParameters);
   }
 
   if (node.implements) {
@@ -21,7 +21,7 @@ export function ClassDeclaration(node, print) {
   }
 
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export { ClassDeclaration as ClassExpression };
@@ -43,22 +43,22 @@ export function ClassBody(node, print) {
 
 
 export function ClassProperty(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
 
   if (node.static) this.push("static ");
-  print(node.key);
+  print.plain(node.key);
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
   if (node.value) {
     this.space();
     this.push("=");
     this.space();
-    print(node.value);
+    print.plain(node.value);
   }
   this.semicolon();
 }
 
 export function MethodDefinition(node, print) {
-  print.list(node.decorators);
+  print.list(node.decorators, { separator: "" });
 
   if (node.static) {
     this.push("static ");

src/babel/generation/generators/comprehensions.js

@@ -1,9 +1,9 @@
 export function ComprehensionBlock(node, print) {
   this.keyword("for");
   this.push("(");
-  print(node.left);
+  print.plain(node.left);
   this.push(" of ");
-  print(node.right);
+  print.plain(node.right);
   this.push(")");
 }
 
@@ -16,12 +16,12 @@ export function ComprehensionExpression(node, print) {
   if (node.filter) {
     this.keyword("if");
     this.push("(");
-    print(node.filter);
+    print.plain(node.filter);
     this.push(")");
     this.space();
   }
 
-  print(node.body);
+  print.plain(node.body);
 
   this.push(node.generator ? ")" : "]");
 }

src/babel/generation/generators/expressions.js

@@ -1,55 +1,60 @@
-import isInteger from "is-integer";
 import isNumber from "lodash/lang/isNumber";
 import * as t from "../../types";
 
 export function UnaryExpression(node, print) {
-  var hasSpace = /[a-z]$/.test(node.operator);
+  var needsSpace = /[a-z]$/.test(node.operator);
   var arg = node.argument;
 
   if (t.isUpdateExpression(arg) || t.isUnaryExpression(arg)) {
-    hasSpace = true;
+    needsSpace = true;
   }
 
   if (t.isUnaryExpression(arg) && arg.operator === "!") {
-    hasSpace = false;
+    needsSpace = false;
   }
 
   this.push(node.operator);
-  if (hasSpace) this.push(" ");
+  if (needsSpace) this.push(" ");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export function DoExpression(node, print) {
   this.push("do");
   this.space();
-  print(node.body);
+  print.plain(node.body);
+}
+
+export function ParenthesizedExpression(node, print) {
+  this.push("(");
+  print.plain(node.expression);
+  this.push(")");
 }
 
 export function UpdateExpression(node, print) {
   if (node.prefix) {
     this.push(node.operator);
-    print(node.argument);
+    print.plain(node.argument);
   } else {
-    print(node.argument);
+    print.plain(node.argument);
     this.push(node.operator);
   }
 }
 
 export function ConditionalExpression(node, print) {
-  print(node.test);
+  print.plain(node.test);
   this.space();
   this.push("?");
   this.space();
-  print(node.consequent);
+  print.plain(node.consequent);
   this.space();
   this.push(":");
   this.space();
-  print(node.alternate);
+  print.plain(node.alternate);
 }
 
 export function NewExpression(node, print) {
   this.push("new ");
-  print(node.callee);
+  print.plain(node.callee);
   this.push("(");
   print.list(node.arguments);
   this.push(")");
@@ -69,27 +74,27 @@ export function Super() {
 
 export function Decorator(node, print) {
   this.push("@");
-  print(node.expression);
+  print.plain(node.expression);
+  this.newline();
 }
 
 export function CallExpression(node, print) {
-  print(node.callee);
+  print.plain(node.callee);
 
   this.push("(");
 
-  var separator = ",";
+  var isPrettyCall = node._prettyCall && !this.format.retainLines && !this.format.compact;
 
-  if (node._prettyCall) {
+  var separator;
-    separator += "\n";
+  if (isPrettyCall) {
+    separator = ",\n";
     this.newline();
     this.indent();
-  } else {
-    separator += " ";
   }
 
-  print.list(node.arguments, { separator: separator });
+  print.list(node.arguments, { separator });
 
-  if (node._prettyCall) {
+  if (isPrettyCall) {
     this.newline();
     this.dedent();
   }
@@ -106,8 +111,8 @@ var buildYieldAwait = function (keyword) {
     }
 
     if (node.argument) {
-      this.space();
+      this.push(" ");
-      print(node.argument);
+      print.plain(node.argument);
     }
   };
 };
@@ -120,36 +125,53 @@ export function EmptyStatement() {
 }
 
 export function ExpressionStatement(node, print) {
-  print(node.expression);
+  print.plain(node.expression);
   this.semicolon();
 }
 
+export function AssignmentPattern(node, print) {
+  print.plain(node.left);
+  this.push(" = ");
+  print.plain(node.right);
+}
+
 export function AssignmentExpression(node, print) {
   // todo: add cases where the spaces can be dropped when in compact mode
-  print(node.left);
+  print.plain(node.left);
-  this.push(" ");
+
+  var spaces = node.operator === "in" || node.operator === "instanceof";
+  spaces = true; // todo: https://github.com/babel/babel/issues/1835
+  this.space(spaces);
+
   this.push(node.operator);
-  this.push(" ");
+
-  print(node.right);
+  if (!spaces) {
+    // space is mandatory to avoid outputting <!--
+    // http://javascript.spec.whatwg.org/#comment-syntax
+    spaces = node.operator === "<" &&
+             t.isUnaryExpression(node.right, { prefix: true, operator: "!" }) &&
+             t.isUnaryExpression(node.right.argument, { prefix: true, operator: "--" });
+  }
+
+  this.space(spaces);
+
+  print.plain(node.right);
 }
 
 export function BindExpression(node, print) {
-  print(node.object);
+  print.plain(node.object);
   this.push("::");
-  print(node.callee);
+  print.plain(node.callee);
 }
 
 export {
   AssignmentExpression as BinaryExpression,
-  AssignmentExpression as LogicalExpression,
+  AssignmentExpression as LogicalExpression
-  AssignmentExpression as AssignmentPattern
 };
 
-var SCIENTIFIC_NOTATION = /e/i;
-
 export function MemberExpression(node, print) {
   var obj = node.object;
-  print(obj);
+  print.plain(obj);
 
   if (!node.computed && t.isMemberExpression(node.property)) {
     throw new TypeError("Got a MemberExpression for MemberExpression property");
@@ -162,21 +184,16 @@ export function MemberExpression(node, print) {
 
   if (computed) {
     this.push("[");
-    print(node.property);
+    print.plain(node.property);
     this.push("]");
   } else {
-    // 5..toFixed(2);
-    if (t.isLiteral(obj) && isInteger(obj.value) && !SCIENTIFIC_NOTATION.test(obj.value.toString())) {
-      this.push(".");
-    }
-
     this.push(".");
-    print(node.property);
+    print.plain(node.property);
   }
 }
 
 export function MetaProperty(node, print) {
-  print(node.meta);
+  print.plain(node.meta);
   this.push(".");
-  print(node.property);
+  print.plain(node.property);
 }

src/babel/generation/generators/flow.js

@@ -5,7 +5,7 @@ export function AnyTypeAnnotation() {
 }
 
 export function ArrayTypeAnnotation(node, print) {
-  print(node.elementType);
+  print.plain(node.elementType);
   this.push("[");
   this.push("]");
 }
@@ -21,27 +21,27 @@ export function DeclareClass(node, print) {
 
 export function DeclareFunction(node, print) {
   this.push("declare function ");
-  print(node.id);
+  print.plain(node.id);
-  print(node.id.typeAnnotation.typeAnnotation);
+  print.plain(node.id.typeAnnotation.typeAnnotation);
   this.semicolon();
 }
 
 export function DeclareModule(node, print) {
   this.push("declare module ");
-  print(node.id);
+  print.plain(node.id);
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function DeclareVariable(node, print) {
   this.push("declare var ");
-  print(node.id);
+  print.plain(node.id);
-  print(node.id.typeAnnotation);
+  print.plain(node.id.typeAnnotation);
   this.semicolon();
 }
 
 export function FunctionTypeAnnotation(node, print, parent) {
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   this.push("(");
   print.list(node.params);
 
@@ -51,7 +51,7 @@ export function FunctionTypeAnnotation(node, print, parent) {
       this.space();
     }
     this.push("...");
-    print(node.rest);
+    print.plain(node.rest);
   }
 
   this.push(")");
@@ -65,33 +65,33 @@ export function FunctionTypeAnnotation(node, print, parent) {
   }
 
   this.space();
-  print(node.returnType);
+  print.plain(node.returnType);
 }
 
 export function FunctionTypeParam(node, print) {
-  print(node.name);
+  print.plain(node.name);
   if (node.optional) this.push("?");
   this.push(":");
   this.space();
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function InterfaceExtends(node, print) {
-  print(node.id);
+  print.plain(node.id);
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
 }
 
 export { InterfaceExtends as ClassImplements, InterfaceExtends as GenericTypeAnnotation };
 
 export function _interfaceish(node, print) {
-  print(node.id);
+  print.plain(node.id);
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   if (node.extends.length) {
     this.push(" extends ");
     print.join(node.extends, { separator: ", " });
   }
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function InterfaceDeclaration(node, print) {
@@ -103,9 +103,13 @@ export function IntersectionTypeAnnotation(node, print) {
   print.join(node.types, { separator: " & " });
 }
 
+export function MixedTypeAnnotation() {
+  this.push("mixed");
+}
+
 export function NullableTypeAnnotation(node, print) {
   this.push("?");
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function NumberTypeAnnotation() {
@@ -128,17 +132,17 @@ export function TupleTypeAnnotation(node, print) {
 
 export function TypeofTypeAnnotation(node, print) {
   this.push("typeof ");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export function TypeAlias(node, print) {
   this.push("type ");
-  print(node.id);
+  print.plain(node.id);
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   this.space();
   this.push("=");
   this.space();
-  print(node.right);
+  print.plain(node.right);
   this.semicolon();
 }
 
@@ -146,7 +150,7 @@ export function TypeAnnotation(node, print) {
   this.push(":");
   this.space();
   if (node.optional) this.push("?");
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
 }
 
 export function TypeParameterInstantiation(node, print) {
@@ -183,37 +187,37 @@ export function ObjectTypeAnnotation(node, print) {
 
 export function ObjectTypeCallProperty(node, print) {
   if (node.static) this.push("static ");
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function ObjectTypeIndexer(node, print) {
   if (node.static) this.push("static ");
   this.push("[");
-  print(node.id);
+  print.plain(node.id);
   this.push(":");
   this.space();
-  print(node.key);
+  print.plain(node.key);
   this.push("]");
   this.push(":");
   this.space();
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function ObjectTypeProperty(node, print) {
   if (node.static) this.push("static ");
-  print(node.key);
+  print.plain(node.key);
   if (node.optional) this.push("?");
   if (!t.isFunctionTypeAnnotation(node.value)) {
     this.push(":");
     this.space();
   }
-  print(node.value);
+  print.plain(node.value);
 }
 
 export function QualifiedTypeIdentifier(node, print) {
-  print(node.qualification);
+  print.plain(node.qualification);
   this.push(".");
-  print(node.id);
+  print.plain(node.id);
 }
 
 export function UnionTypeAnnotation(node, print) {
@@ -222,8 +226,8 @@ export function UnionTypeAnnotation(node, print) {
 
 export function TypeCastExpression(node, print) {
   this.push("(");
-  print(node.expression);
+  print.plain(node.expression);
-  print(node.typeAnnotation);
+  print.plain(node.typeAnnotation);
   this.push(")");
 }
 

src/babel/generation/generators/jsx.js

@@ -1,11 +1,10 @@
-import each from "lodash/collection/each";
 import * as t from "../../types";
 
 export function JSXAttribute(node, print) {
-  print(node.name);
+  print.plain(node.name);
   if (node.value) {
     this.push("=");
-    print(node.value);
+    print.plain(node.value);
   }
 }
 
@@ -14,32 +13,32 @@ export function JSXIdentifier(node) {
 }
 
 export function JSXNamespacedName(node, print) {
-  print(node.namespace);
+  print.plain(node.namespace);
   this.push(":");
-  print(node.name);
+  print.plain(node.name);
 }
 
 export function JSXMemberExpression(node, print) {
-  print(node.object);
+  print.plain(node.object);
   this.push(".");
-  print(node.property);
+  print.plain(node.property);
 }
 
 export function JSXSpreadAttribute(node, print) {
   this.push("{...");
-  print(node.argument);
+  print.plain(node.argument);
   this.push("}");
 }
 
 export function JSXExpressionContainer(node, print) {
   this.push("{");
-  print(node.expression);
+  print.plain(node.expression);
   this.push("}");
 }
 
 export function JSXElement(node, print) {
   var open = node.openingElement;
-  print(open);
+  print.plain(open);
   if (open.selfClosing) return;
 
   this.indent();
@@ -47,17 +46,17 @@ export function JSXElement(node, print) {
     if (t.isLiteral(child)) {
       this.push(child.value, true);
     } else {
-      print(child);
+      print.plain(child);
     }
   }
   this.dedent();
 
-  print(node.closingElement);
+  print.plain(node.closingElement);
 }
 
 export function JSXOpeningElement(node, print) {
   this.push("<");
-  print(node.name);
+  print.plain(node.name);
   if (node.attributes.length > 0) {
     this.push(" ");
     print.join(node.attributes, { separator: " " });
@@ -67,7 +66,7 @@ export function JSXOpeningElement(node, print) {
 
 export function JSXClosingElement(node, print) {
   this.push("</");
-  print(node.name);
+  print.plain(node.name);
   this.push(">");
 }
 

src/babel/generation/generators/methods.js

@@ -1,18 +1,18 @@
 import * as t from "../../types";
 
 export function _params(node, print) {
-  print(node.typeParameters);
+  print.plain(node.typeParameters);
   this.push("(");
   print.list(node.params, {
     iterator: (node) =>{
       if (node.optional) this.push("?");
-      print(node.typeAnnotation);
+      print.plain(node.typeAnnotation);
     }
   });
   this.push(")");
 
   if (node.returnType) {
-    print(node.returnType);
+    print.plain(node.returnType);
   }
 }
 
@@ -35,15 +35,15 @@ export function _method(node, print) {
 
   if (node.computed) {
     this.push("[");
-    print(key);
+    print.plain(key);
     this.push("]");
   } else {
-    print(key);
+    print.plain(key);
   }
 
   this._params(value, print);
-  this.push(" ");
+  this.space();
-  print(value.body);
+  print.plain(value.body);
 }
 
 export function FunctionExpression(node, print) {
@@ -53,14 +53,14 @@ export function FunctionExpression(node, print) {
 
   if (node.id) {
     this.push(" ");
-    print(node.id);
+    print.plain(node.id);
   } else {
     this.space();
   }
 
   this._params(node, print);
   this.space();
-  print(node.body);
+  print.plain(node.body);
 }
 
 export { FunctionExpression as FunctionDeclaration };
@@ -69,7 +69,7 @@ export function ArrowFunctionExpression(node, print) {
   if (node.async) this.push("async ");
 
   if (node.params.length === 1 && t.isIdentifier(node.params[0])) {
-    print(node.params[0]);
+    print.plain(node.params[0]);
   } else {
     this._params(node, print);
   }
@@ -82,7 +82,7 @@ export function ArrowFunctionExpression(node, print) {
     this.push("(");
   }
 
-  print(node.body);
+  print.plain(node.body);
 
   if (bodyNeedsParens) {
     this.push(")");

src/babel/generation/generators/modules.js

@@ -1,43 +1,42 @@
-import each from "lodash/collection/each";
 import * as t from "../../types";
 
 export function ImportSpecifier(node, print) {
-  print(node.imported);
+  print.plain(node.imported);
   if (node.local && node.local.name !== node.imported.name) {
     this.push(" as ");
-    print(node.local);
+    print.plain(node.local);
   }
 }
 
 export function ImportDefaultSpecifier(node, print) {
-  print(node.local);
+  print.plain(node.local);
 }
 
 export function ExportDefaultSpecifier(node, print) {
-  print(node.exported);
+  print.plain(node.exported);
 }
 
 export function ExportSpecifier(node, print) {
-  print(node.local);
+  print.plain(node.local);
   if (node.exported && node.local.name !== node.exported.name) {
     this.push(" as ");
-    print(node.exported);
+    print.plain(node.exported);
   }
 }
 
 export function ExportNamespaceSpecifier(node, print) {
   this.push("* as ");
-  print(node.exported);
+  print.plain(node.exported);
 }
 
 export function ExportAllDeclaration(node, print) {
   this.push("export *");
   if (node.exported) {
     this.push(" as ");
-    print(node.exported);
+    print.plain(node.exported);
   }
   this.push(" from ");
-  print(node.source);
+  print.plain(node.source);
   this.semicolon();
 }
 
@@ -56,14 +55,14 @@ function ExportDeclaration(node, print) {
 
   if (node.declaration) {
     var declar = node.declaration;
-    print(declar);
+    print.plain(declar);
     if (t.isStatement(declar) || t.isFunction(declar) || t.isClass(declar)) return;
   } else {
     var first = specifiers[0];
     var hasSpecial = false;
     if (t.isExportDefaultSpecifier(first) || t.isExportNamespaceSpecifier(first)) {
       hasSpecial = true;
-      print(specifiers.shift());
+      print.plain(specifiers.shift());
       if (specifiers.length) {
         this.push(", ");
       }
@@ -81,7 +80,7 @@ function ExportDeclaration(node, print) {
 
     if (node.source) {
       this.push(" from ");
-      print(node.source);
+      print.plain(node.source);
     }
   }
 
@@ -99,7 +98,7 @@ export function ImportDeclaration(node, print) {
   if (specfiers && specfiers.length) {
     var first = node.specifiers[0];
     if (t.isImportDefaultSpecifier(first) || t.isImportNamespaceSpecifier(first)) {
-      print(node.specifiers.shift());
+      print.plain(node.specifiers.shift());
       if (node.specifiers.length) {
         this.push(", ");
       }
@@ -107,20 +106,20 @@ export function ImportDeclaration(node, print) {
 
     if (node.specifiers.length) {
       this.push("{");
-      this.space()
+      this.space();
       print.join(node.specifiers, { separator: ", " });
-      this.space()
+      this.space();
       this.push("}");
     }
 
     this.push(" from ");
   }
 
-  print(node.source);
+  print.plain(node.source);
   this.semicolon();
 }
 
 export function ImportNamespaceSpecifier(node, print) {
   this.push("* as ");
-  print(node.local);
+  print.plain(node.local);
 }

src/babel/generation/generators/statements.js

@@ -4,7 +4,7 @@ import * as t from "../../types";
 export function WithStatement(node, print) {
   this.keyword("with");
   this.push("(");
-  print(node.object);
+  print.plain(node.object);
   this.push(")");
   print.block(node.body);
 }
@@ -12,7 +12,7 @@ export function WithStatement(node, print) {
 export function IfStatement(node, print) {
   this.keyword("if");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(")");
   this.space();
 
@@ -29,18 +29,18 @@ export function ForStatement(node, print) {
   this.keyword("for");
   this.push("(");
 
-  print(node.init);
+  print.plain(node.init);
   this.push(";");
 
   if (node.test) {
-    this.push(" ");
+    this.space();
-    print(node.test);
+    print.plain(node.test);
   }
   this.push(";");
 
   if (node.update) {
-    this.push(" ");
+    this.space();
-    print(node.update);
+    print.plain(node.update);
   }
 
   this.push(")");
@@ -50,7 +50,7 @@ export function ForStatement(node, print) {
 export function WhileStatement(node, print) {
   this.keyword("while");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(")");
   print.block(node.body);
 }
@@ -59,9 +59,9 @@ var buildForXStatement = function (op) {
   return function (node, print) {
     this.keyword("for");
     this.push("(");
-    print(node.left);
+    print.plain(node.left);
     this.push(` ${op} `);
-    print(node.right);
+    print.plain(node.right);
     this.push(")");
     print.block(node.body);
   };
@@ -72,11 +72,11 @@ export var ForOfStatement = buildForXStatement("of");
 
 export function DoWhileStatement(node, print) {
   this.push("do ");
-  print(node.body);
+  print.plain(node.body);
   this.space();
   this.keyword("while");
   this.push("(");
-  print(node.test);
+  print.plain(node.test);
   this.push(");");
 }
 
@@ -87,7 +87,7 @@ var buildLabelStatement = function (prefix, key) {
     var label = node[key || "label"];
     if (label) {
       this.push(" ");
-      print(label);
+      print.plain(label);
     }
 
     this.semicolon();
@@ -99,50 +99,50 @@ export var ReturnStatement   = buildLabelStatement("return", "argument");
 export var BreakStatement    = buildLabelStatement("break");
 
 export function LabeledStatement(node, print) {
-  print(node.label);
+  print.plain(node.label);
   this.push(": ");
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function TryStatement(node, print) {
   this.keyword("try");
-  print(node.block);
+  print.plain(node.block);
   this.space();
 
   // Esprima bug puts the catch clause in a `handlers` array.
   // see https://code.google.com/p/esprima/issues/detail?id=433
   // We run into this from regenerator generated ast.
   if (node.handlers) {
-    print(node.handlers[0]);
+    print.plain(node.handlers[0]);
   } else {
-    print(node.handler);
+    print.plain(node.handler);
   }
 
   if (node.finalizer) {
     this.space();
     this.push("finally ");
-    print(node.finalizer);
+    print.plain(node.finalizer);
   }
 }
 
 export function CatchClause(node, print) {
   this.keyword("catch");
   this.push("(");
-  print(node.param);
+  print.plain(node.param);
   this.push(") ");
-  print(node.body);
+  print.plain(node.body);
 }
 
 export function ThrowStatement(node, print) {
   this.push("throw ");
-  print(node.argument);
+  print.plain(node.argument);
   this.semicolon();
 }
 
 export function SwitchStatement(node, print) {
   this.keyword("switch");
   this.push("(");
-  print(node.discriminant);
+  print.plain(node.discriminant);
   this.push(")");
   this.space();
   this.push("{");
@@ -160,7 +160,7 @@ export function SwitchStatement(node, print) {
 export function SwitchCase(node, print) {
   if (node.test) {
     this.push("case ");
-    print(node.test);
+    print.plain(node.test);
     this.push(":");
   } else {
     this.push("default:");
@@ -190,16 +190,29 @@ export function VariableDeclaration(node, print, parent) {
     }
   }
 
-  var sep = ",";
+  //
+  // use a pretty separator when we aren't in compact mode, have initializers and don't have retainLines on
+  // this will format declarations like:
+  //
+  //   var foo = "bar", bar = "foo";
+  //
+  // into
+  //
+  //   var foo = "bar",
+  //       bar = "foo";
+  //
+
+  var sep;
   if (!this.format.compact && !this.format.concise && hasInits && !this.format.retainLines) {
-    sep += `\n${repeating(" ", node.kind.length + 1)}`;
+    sep = `,\n${repeating(" ", node.kind.length + 1)}`;
-  } else {
-    sep += " ";
   }
 
+  //
+
   print.list(node.declarations, { separator: sep });
 
   if (t.isFor(parent)) {
+    // don't give semicolons to these nodes since they'll be inserted in the parent generator
     if (parent.left === node || parent.init === node) return;
   }
 
@@ -207,12 +220,12 @@ export function VariableDeclaration(node, print, parent) {
 }
 
 export function VariableDeclarator(node, print) {
-  print(node.id);
+  print.plain(node.id);
-  print(node.id.typeAnnotation);
+  print.plain(node.id.typeAnnotation);
   if (node.init) {
     this.space();
     this.push("=");
     this.space();
-    print(node.init);
+    print.plain(node.init);
   }
 }

src/babel/generation/generators/template-literals.js

@@ -1,8 +1,6 @@
-import each from "lodash/collection/each";
-
 export function TaggedTemplateExpression(node, print) {
-  print(node.tag);
+  print.plain(node.tag);
-  print(node.quasi);
+  print.plain(node.quasi);
 }
 
 export function TemplateElement(node) {
@@ -16,11 +14,11 @@ export function TemplateLiteral(node, print) {
   var len    = quasis.length;
 
   for (var i = 0; i < len; i++) {
-    print(quasis[i]);
+    print.plain(quasis[i]);
 
     if (i + 1 < len) {
       this.push("${ ");
-      print(node.expressions[i]);
+      print.plain(node.expressions[i]);
       this.push(" }");
     }
   }

src/babel/generation/generators/types.js

@@ -1,4 +1,6 @@
-import each from "lodash/collection/each";
+/* eslint quotes: 0 */
+
+import isInteger from "is-integer";
 import * as t from "../../types";
 
 export function Identifier(node) {
@@ -7,7 +9,7 @@ export function Identifier(node) {
 
 export function RestElement(node, print) {
   this.push("...");
-  print(node.argument);
+  print.plain(node.argument);
 }
 
 export { RestElement as SpreadElement, RestElement as SpreadProperty };
@@ -31,15 +33,23 @@ export function ObjectExpression(node, print) {
 export { ObjectExpression as ObjectPattern };
 
 export function Property(node, print) {
+  print.list(node.decorators, { separator: "" });
+
   if (node.method || node.kind === "get" || node.kind === "set") {
     this._method(node, print);
   } else {
     if (node.computed) {
       this.push("[");
-      print(node.key);
+      print.plain(node.key);
       this.push("]");
     } else {
-      print(node.key);
+      // print `({ foo: foo = 5 } = {})` as `({ foo = 5 } = {});`
+      if (t.isAssignmentPattern(node.value) && t.isIdentifier(node.key) && node.key.name === node.value.left.name) {
+        print.plain(node.value);
+        return;
+      }
+
+      print.plain(node.key);
 
       // shorthand!
       if (node.shorthand &&
@@ -52,7 +62,7 @@ export function Property(node, print) {
 
     this.push(":");
     this.space();
-    print(node.value);
+    print.plain(node.value);
   }
 }
 
@@ -72,8 +82,8 @@ export function ArrayExpression(node, print) {
       // both (all) of the holes.
       this.push(",");
     } else {
-      if (i > 0) this.push(" ");
+      if (i > 0) this.space();
-      print(elem);
+      print.plain(elem);
       if (i < len - 1) this.push(",");
     }
   }
@@ -83,14 +93,29 @@ export function ArrayExpression(node, print) {
 
 export { ArrayExpression as ArrayPattern };
 
-export function Literal(node) {
+const SCIENTIFIC_NOTATION = /e/i;
+
+export function Literal(node, print, parent) {
   var val  = node.value;
   var type = typeof val;
 
   if (type === "string") {
     this._stringLiteral(val);
   } else if (type === "number") {
-    this.push(val + "");
+    // check to see if this is the same number as the raw one in the original source as asm.js uses
+    // numbers in the form 5.0 for type hinting
+    var raw = node.raw;
+    if (val === +raw && raw[raw.length - 1] !== "." && !/^0[bo]/i.test(raw)) {
+      val = raw;
+    }
+
+    val = val + "";
+
+    if (isInteger(+val) && t.isMemberExpression(parent, { object: node }) && !SCIENTIFIC_NOTATION.test(val)) {
+      val += ".";
+    }
+
+    this.push(val);
   } else if (type === "boolean") {
     this.push(val ? "true" : "false");
   } else if (node.regex) {
@@ -109,9 +134,16 @@ export function _stringLiteral(val) {
   });
 
   if (this.format.quotes === "single") {
+    // remove double quotes
     val = val.slice(1, -1);
+
+    // unescape double quotes
     val = val.replace(/\\"/g, '"');
+
+    // escape single quotes
     val = val.replace(/'/g, "\\'");
+
+    // add single quotes
     val = `'${val}'`;
   }
 

src/babel/generation/index.js

@@ -1,5 +1,6 @@
 import detectIndent from "detect-indent";
 import Whitespace from "./whitespace";
+import NodePrinter from "./node/printer";
 import repeating from "repeating";
 import SourceMap from "./source-map";
 import Position from "./position";
@@ -20,7 +21,7 @@ class CodeGenerator {
     this.opts     = opts;
     this.ast      = ast;
 
-    this.whitespace = new Whitespace(this.tokens, this.comments, this.format);
+    this.whitespace = new Whitespace(this.tokens);
     this.position   = new Position;
     this.map        = new SourceMap(this.position, opts, code);
     this.buffer     = new Buffer(this.position, this.format);
@@ -67,7 +68,6 @@ class CodeGenerator {
     for (var i = 0; i < tokens.length; i++) {
       var token = tokens[i];
       if (token.type.label !== "string") continue;
-      if (checked >= 3) continue;
 
       var raw = code.slice(token.start, token.end);
       if (raw[0] === "'") {
@@ -77,6 +77,7 @@ class CodeGenerator {
       }
 
       checked++;
+      if (checked >= 3) break;
     }
 
     if (occurences.single > occurences.double) {
@@ -120,40 +121,14 @@ class CodeGenerator {
   }
 
   buildPrint(parent) {
-    var print = (node, opts) => {
+    return new NodePrinter(this, parent);
-      return this.print(node, parent, opts);
-    };
-
-    print.sequence = (nodes, opts = {}) => {
-      opts.statement = true;
-      return this.printJoin(print, nodes, opts);
-    };
-
-    print.join = (nodes, opts) => {
-      return this.printJoin(print, nodes, opts);
-    };
-
-    print.list = function (items, opts = {}) {
-      if (opts.separator == null) opts.separator = ", ";
-      print.join(items, opts);
-    };
-
-    print.block = (node) => {
-      return this.printBlock(print, node);
-    };
-
-    print.indentOnComments = (node) => {
-      return this.printAndIndentOnComments(print, node);
-    };
-
-    return print;
   }
 
-  catchUp(node, parent) {
+  catchUp(node, parent, leftParenPrinted) {
     // catch up to this nodes newline if we're behind
     if (node.loc && this.format.retainLines && this.buffer.buf) {
       var needsParens = false;
-      if (parent && this.position.line < node.loc.start.line && t.isTerminatorless(parent)) {
+      if (!leftParenPrinted && parent && this.position.line < node.loc.start.line && t.isTerminatorless(parent)) {
         needsParens = true;
         this._push("(");
       }
@@ -165,6 +140,36 @@ class CodeGenerator {
     return false;
   }
 
+  _printNewline(leading, node, parent, opts) {
+    if (!opts.statement && !n.isUserWhitespacable(node, parent)) {
+      return;
+    }
+
+    var lines = 0;
+
+    if (node.start != null && !node._ignoreUserWhitespace) {
+      // user node
+      if (leading) {
+        lines = this.whitespace.getNewlinesBefore(node);
+      } else {
+        lines = this.whitespace.getNewlinesAfter(node);
+      }
+    } else {
+      // generated node
+      if (!leading) lines++; // always include at least a single line after
+      if (opts.addNewlines) lines += opts.addNewlines(leading, node) || 0;
+
+      var needs = n.needsWhitespaceAfter;
+      if (leading) needs = n.needsWhitespaceBefore;
+      if (needs(node, parent)) lines++;
+
+      // generated nodes can't add starting file whitespace
+      if (!this.buffer.buf) lines = 0;
+    }
+
+    this.newline(lines);
+  }
+
   print(node, parent, opts = {}) {
     if (!node) return;
 
@@ -177,36 +182,6 @@ class CodeGenerator {
       this.format.concise = true;
     }
 
-    var newline = (leading) => {
-      if (!opts.statement && !n.isUserWhitespacable(node, parent)) {
-        return;
-      }
-
-      var lines = 0;
-
-      if (node.start != null && !node._ignoreUserWhitespace) {
-        // user node
-        if (leading) {
-          lines = this.whitespace.getNewlinesBefore(node);
-        } else {
-          lines = this.whitespace.getNewlinesAfter(node);
-        }
-      } else {
-        // generated node
-        if (!leading) lines++; // always include at least a single line after
-        if (opts.addNewlines) lines += opts.addNewlines(leading, node) || 0;
-
-        var needs = n.needsWhitespaceAfter;
-        if (leading) needs = n.needsWhitespaceBefore;
-        if (needs(node, parent)) lines++;
-
-        // generated nodes can't add starting file whitespace
-        if (!this.buffer.buf) lines = 0;
-      }
-
-      this.newline(lines);
-    };
-
     if (this[node.type]) {
       var needsNoLineTermParens = n.needsParensNoLineTerminator(node, parent);
       var needsParens           = needsNoLineTermParens || n.needsParens(node, parent);
@@ -216,9 +191,9 @@ class CodeGenerator {
 
       this.printLeadingComments(node, parent);
 
-      var needsParensFromCatchup = this.catchUp(node, parent);
+      var needsParensFromCatchup = this.catchUp(node, parent, needsParens);
 
-      newline(true);
+      this._printNewline(true, node, parent, opts);
 
       if (opts.before) opts.before();
       this.map.mark(node, "start");
@@ -236,7 +211,7 @@ class CodeGenerator {
 
       this.format.concise = oldConcise;
 
-      newline(false);
+      this._printNewline(false, node, parent, opts);
 
       this.printTrailingComments(node, parent);
     } else {
@@ -251,21 +226,23 @@ class CodeGenerator {
 
     if (opts.indent) this.indent();
 
+    var printOpts = {
+      statement: opts.statement,
+      addNewlines: opts.addNewlines,
+      after: () => {
+        if (opts.iterator) {
+          opts.iterator(node, i);
+        }
+
+        if (opts.separator && i < len - 1) {
+          this.push(opts.separator);
+        }
+      }
+    };
+
     for (var i = 0; i < nodes.length; i++) {
       var node = nodes[i];
-      print(node, {
+      print.plain(node, printOpts);
-        statement: opts.statement,
-        addNewlines: opts.addNewlines,
-        after: () => {
-          if (opts.iterator) {
-            opts.iterator(node, i);
-          }
-
-          if (opts.separator && i < len - 1) {
-            this.push(opts.separator);
-          }
-        }
-      });
     }
 
     if (opts.indent) this.dedent();
@@ -274,7 +251,7 @@ class CodeGenerator {
   printAndIndentOnComments(print, node) {
     var indent = !!node.leadingComments;
     if (indent) this.indent();
-    print(node);
+    print.plain(node);
     if (indent) this.dedent();
   }
 
@@ -283,13 +260,13 @@ class CodeGenerator {
       this.semicolon();
     } else {
       this.push(" ");
-      print(node);
+      print.plain(node);
     }
   }
 
   generateComment(comment) {
     var val = comment.value;
-    if (comment.type === "Line") {
+    if (comment.type === "CommentLine") {
       val = `//${val}`;
     } else {
       val = `/*${val}*/`;
@@ -317,7 +294,7 @@ class CodeGenerator {
       nodes.push(node.argument);
     }
 
-    for (var node of (nodes: Array)) {
+    for (let node of (nodes: Array)) {
       comments = comments.concat(this._getComments(key, node));
     }
 
@@ -330,7 +307,6 @@ class CodeGenerator {
 
   _printComments(comments) {
     if (this.format.compact) return;
-
     if (!this.format.comments) return;
     if (!comments || !comments.length) return;
 
@@ -366,8 +342,8 @@ class CodeGenerator {
       }
 
       //
-      if (comment.type === "Block" && this.format.indent.adjustMultilineComment) {
+      if (comment.type === "CommentBlock" && this.format.indent.adjustMultilineComment) {
-        var offset = comment.loc.start.column;
+        var offset = comment.loc && comment.loc.start.column;
         if (offset) {
           var newlineRegex = new RegExp("\\n\\s{1," + offset + "}", "g");
           val = val.replace(newlineRegex, "\n");
@@ -383,7 +359,7 @@ class CodeGenerator {
 
       // force a newline for line comments when retainLines is set in case the next printed node
       // doesn't catch up
-      if (this.format.retainLines && comment.type === "Line") {
+      if (this.format.retainLines && comment.type === "CommentLine") {
         val += "\n";
       }
 

src/babel/generation/node/printer.js

@@ -0,0 +1,36 @@
+export default class NodePrinter {
+  constructor(generator, parent) {
+    this.generator = generator;
+    this.parent = parent;
+  }
+
+  plain(node, opts) {
+    return this.generator.print(node, this.parent, opts);
+  }
+
+  sequence(nodes, opts = {}) {
+    opts.statement = true;
+    return this.generator.printJoin(this, nodes, opts);
+  }
+
+  join(nodes, opts) {
+    return this.generator.printJoin(this, nodes, opts);
+  }
+
+  list(items, opts = {}) {
+    if (opts.separator == null) {
+      opts.separator = ",";
+      if (!this.generator.format.compact) opts.separator += " ";
+    }
+
+    return this.join(items, opts);
+  }
+
+  block(node) {
+    return this.generator.printBlock(this, node);
+  }
+
+  indentOnComments(node) {
+    return this.generator.printAndIndentOnComments(this, node);
+  }
+}

src/babel/generation/source-map.js

@@ -8,7 +8,7 @@ export default class SourceMap {
 
     if (opts.sourceMaps) {
       this.map = new sourceMap.SourceMapGenerator({
-        file: opts.sourceMapName,
+        file: opts.sourceMapTarget,
         sourceRoot: opts.sourceRoot
       });
 

src/babel/generation/whitespace.js

@@ -1,5 +1,3 @@
-import sortBy from "lodash/collection/sortBy";
-
 /**
  * Returns `i`th number from `base`, continuing from 0 when `max` is reached.
  * Useful for shifting `for` loop by a fixed number but going over all items.
@@ -21,8 +19,8 @@ function getLookupIndex(i, base, max) {
 }
 
 export default class Whitespace {
-  constructor(tokens, comments) {
+  constructor(tokens) {
-    this.tokens = sortBy(tokens.concat(comments), "start");
+    this.tokens = tokens;
     this.used   = {};
 
     // Profiling this code shows that while generator passes over it, indexes
@@ -40,12 +38,11 @@ export default class Whitespace {
     var startToken;
     var endToken;
     var tokens = this.tokens;
-    var token;
 
     for (var j = 0; j < tokens.length; j++) {
       // optimize for forward traversal by shifting for loop index
       var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
-      token = tokens[i];
+      var token = tokens[i];
 
       // this is the token this node starts with
       if (node.start === token.start) {
@@ -64,17 +61,17 @@ export default class Whitespace {
     var startToken;
     var endToken;
     var tokens = this.tokens;
-    var token;
 
     for (var j = 0; j < tokens.length; j++) {
       // optimize for forward traversal by shifting for loop index
       var i = getLookupIndex(j, this._lastFoundIndex, this.tokens.length);
-      token = tokens[i];
+      var token = tokens[i];
 
       // this is the token this node ends with
       if (node.end === token.end) {
         startToken = token;
         endToken = tokens[i + 1];
+        if (endToken.type.label === ",") endToken = tokens[i + 2];
 
         this._lastFoundIndex = i;
         break;
@@ -85,7 +82,7 @@ export default class Whitespace {
       return 1;
     } else {
       var lines = this.getNewlinesBetween(startToken, endToken);
-      if (node.type === "Line" && !lines) {
+      if (node.type === "CommentLine" && !lines) {
         // line comment
         return 1;
       } else {

src/babel/helpers/code-frame.js

@@ -79,10 +79,12 @@ export default function (lines: number, lineNumber: number, colNumber: number, o
       if (params.number !== lineNumber) {
         return;
       }
+
       if (colNumber) {
         params.line += `\n${params.before}${repeating(" ", params.width)}${params.after}${repeating(" ", colNumber - 1)}^`;
       }
+
       params.before = params.before.replace(/^./, ">");
     }
   }).join("\n");
-};
+}

src/babel/helpers/normalize-ast.js

@@ -6,4 +6,4 @@ export default function (ast, comments, tokens) {
   } else {
     throw new Error("Not a valid ast?");
   }
-};
+}

src/babel/helpers/object.js

@@ -1,3 +1,3 @@
 export default function () {
   return Object.create(null);
-};
+}

src/babel/helpers/parse.js

@@ -3,8 +3,9 @@ import estraverse from "estraverse";
 import * as acorn from "../../acorn";
 
 export default function (code, opts = {}) {
-  var comments = [];
+  var commentsAndTokens = [];
-  var tokens   = [];
+  var comments          = [];
+  var tokens            = [];
 
   var parseOpts = {
     allowImportExportEverywhere: opts.looseModules,
@@ -14,21 +15,38 @@ export default function (code, opts = {}) {
     strictMode:                  opts.strictMode,
     sourceType:                  opts.sourceType,
     locations:                   true,
-    onComment:                   comments,
     features:                    opts.features || {},
     plugins:                     opts.plugins || {},
     onToken:                     tokens,
     ranges:                      true
   };
 
+  parseOpts.onToken = function (token) {
+    tokens.push(token);
+    commentsAndTokens.push(token);
+  };
+
+  parseOpts.onComment = function (block, text, start, end, startLoc, endLoc) {
+    var comment = {
+      type: block ? "CommentBlock" : "CommentLine",
+      value: text,
+      start: start,
+      end: end,
+      loc: new acorn.SourceLocation(this, startLoc, endLoc),
+      range: [start, end]
+    };
+
+    commentsAndTokens.push(comment);
+    comments.push(comment);
+  };
+
   if (opts.nonStandard) {
     parseOpts.plugins.jsx = true;
     parseOpts.plugins.flow = true;
   }
 
   var ast = acorn.parse(code, parseOpts);
-
   estraverse.attachComments(ast, comments, tokens);
-  ast = normalizeAst(ast, comments, tokens);
+  ast = normalizeAst(ast, comments, commentsAndTokens);
   return ast;
 }

src/babel/messages.js

@@ -5,23 +5,26 @@ export const MESSAGES = {
   JSXNamespacedTags: "Namespace tags are not supported. ReactJSX is not XML.",
   classesIllegalBareSuper: "Illegal use of bare super",
   classesIllegalSuperCall: "Direct super call is illegal in non-constructor, use super.$1() instead",
-  classesIllegalConstructorKind: "Illegal kind for constructor method",
   scopeDuplicateDeclaration: "Duplicate declaration $1",
-  undeclaredVariable: "Reference to undeclared variable $1",
-  undeclaredVariableSuggestion: "Reference to undeclared variable $1 - did you mean $2?",
-  settersInvalidParamLength: "Setters must have exactly one parameter",
   settersNoRest: "Setters aren't allowed to have a rest",
   noAssignmentsInForHead: "No assignments allowed in for-in/of head",
-  expectedMemberExpressionOrIdentifier: "Expected type MemeberExpression or Identifier",
+  expectedMemberExpressionOrIdentifier: "Expected type MemberExpression or Identifier",
   invalidParentForThisNode: "We don't know how to handle this node within the current parent - please open an issue",
   readOnly: "$1 is read-only",
-  modulesIllegalExportName: "Illegal export $1",
   unknownForHead: "Unknown node type $1 in ForStatement",
   didYouMean: "Did you mean $1?",
   codeGeneratorDeopt: "Note: The code generator has deoptimised the styling of $1 as it exceeds the max of $2.",
   missingTemplatesDirectory: "no templates directory - this is most likely the result of a broken `npm publish`. Please report to https://github.com/babel/babel/issues",
   unsupportedOutputType: "Unsupported output type $1",
   illegalMethodName: "Illegal method name $1",
+  lostTrackNodePath: "We lost track of this nodes position, likely because the AST was directly manipulated",
+
+  modulesIllegalExportName: "Illegal export $1",
+  modulesDuplicateDeclarations: "Duplicate module declarations with the same source but in different scopes",
+
+  undeclaredVariable: "Reference to undeclared variable $1",
+  undeclaredVariableType: "Referencing a type alias outside of a type annotation",
+  undeclaredVariableSuggestion: "Reference to undeclared variable $1 - did you mean $2?",
 
   traverseNeedsParent: "Must pass a scope and parentPath unless traversing a Program/File got a $1 node",
   traverseVerifyRootFunction: "You passed `traverse()` a function when it expected a visitor object, are you sure you didn't mean `{ enter: Function }`?",
@@ -31,10 +34,10 @@ export const MESSAGES = {
   pluginIllegalKind: "Illegal kind $1 for plugin $2",
   pluginIllegalPosition: "Illegal position $1 for plugin $2",
   pluginKeyCollision: "The plugin $1 collides with another of the same name",
-  pluginNotTransformer: "The plugin $1 didn't export a Transformer instance",
+  pluginNotTransformer: "The plugin $1 didn't export a Plugin instance",
   pluginUnknown: "Unknown plugin $1",
 
-  transformerNotFile: "Transformer $1 is resolving to a different Babel version to what is doing the actual transformation..."
+  pluginNotFile: "Plugin $1 is resolving to a different Babel version to what is doing the actual transformation..."
 };
 
 export function get(key: String, ...args) {

src/babel/patch.js

@@ -17,6 +17,8 @@ var or  = types.Type.or;
 //  .build("program")
 //  .field("program", def("Program"));
 
+def("Noop");
+
 def("AssignmentPattern")
   .bases("Pattern")
   .build("left", "right")

src/babel/tools/build-external-helpers.js

@@ -83,4 +83,4 @@ export default function (whitelist, outputType = "global") {
   }
 
   return generator(tree).code;
-};
+}

src/babel/tools/protect.js

@@ -0,0 +1,9 @@
+import path from "path";
+
+var root = path.resolve(__dirname, "../../../");
+
+export default function (module) {
+  if (module.parent && module.parent.filename.indexOf(root) !== 0) {
+    throw new Error("Don't hotlink internal Babel files.");
+  }
+}

src/babel/transformation/file/index.js

@@ -1,15 +1,13 @@
+import { validateOption, normaliseOptions, config as optionsConfig } from "./options";
 import convertSourceMap from "convert-source-map";
-import * as optionParsers from "./option-parsers";
 import moduleFormatters from "../modules";
 import PluginManager from "./plugin-manager";
 import shebangRegex from "shebang-regex";
-import TraversalPath from "../../traversal/path";
+import NodePath from "../../traversal/path";
-import Transformer from "../transformer";
 import isFunction from "lodash/lang/isFunction";
 import isAbsolute from "path-is-absolute";
-import resolveRc from "../../tools/resolve-rc";
+import resolveRc from "./options/resolve-rc";
 import sourceMap from "source-map";
-import transform from "./../index";
 import generate from "../../generation";
 import codeFrame from "../../helpers/code-frame";
 import defaults from "lodash/object/defaults";
@@ -17,13 +15,13 @@ import includes from "lodash/collection/includes";
 import traverse from "../../traversal";
 import assign from "lodash/object/assign";
 import Logger from "./logger";
+import Plugin from "../plugin";
 import parse from "../../helpers/parse";
-import Scope from "../../traversal/scope";
 import merge from "../../helpers/merge";
 import slash from "slash";
 import clone from "lodash/lang/clone";
+import Hub from "../../traversal/hub";
 import * as util from  "../../util";
-import * as api from  "../../api/node";
 import path from "path";
 import * as t from "../../types";
 
@@ -38,15 +36,27 @@ export default class File {
     this.declarations = {};
     this.usedHelpers  = {};
     this.dynamicData  = {};
-    this.metadata     = {};
     this.data         = {};
 
+    this.metadata = {
+      modules: {
+        imports: [],
+        exports: {
+          exported: [],
+          specifiers: []
+        }
+      }
+    };
+
     this.pipeline = pipeline;
     this.log      = new Logger(this, opts.filename || "unknown");
-    this.opts     = this.normalizeOptions(opts);
     this.ast      = {};
 
+    this.normaliseOptions(opts);
+
     this.buildTransformers();
+
+    this.hub = new Hub(this);
   }
 
   static helpers = [
@@ -88,19 +98,19 @@ export default class File {
 
   static soloHelpers = [];
 
-  static options = require("./options");
+  static options = optionsConfig;
 
-  normalizeOptions(opts: Object) {
+  normaliseOptions(opts: Object) {
-    opts = assign({}, opts);
+    opts = this.opts = normaliseOptions(assign({}, opts));
 
+    // resolve babelrc
     if (opts.filename) {
       var rcFilename = opts.filename;
       if (!isAbsolute(rcFilename)) rcFilename = path.join(process.cwd(), rcFilename);
       opts = resolveRc(rcFilename, opts);
     }
 
-    //
+    // check for unknown options
-
     for (let key in opts) {
       if (key[0] === "_") continue;
 
@@ -108,26 +118,30 @@ export default class File {
       if (!option) this.log.error(`Unknown option: ${key}`, ReferenceError);
     }
 
+    // merge in environment options
     var envKey = process.env.BABEL_ENV || process.env.NODE_ENV || "development";
-    if (opts.env) merge(opts, opts.env[envKey]);
+    if (opts.env) merge(opts, normaliseOptions(opts.env[envKey]));
 
+    // normalise options
     for (let key in File.options) {
       let option = File.options[key];
+      var val    = opts[key];
 
-      var val = opts[key];
+      // optional
       if (!val && option.optional) continue;
 
+      // deprecated
       if (val && option.deprecated) {
-        throw new Error("Deprecated option " + key + ": " + option.deprecated);
+        this.log.deprecate("Deprecated option " + key + ": " + option.deprecated);
       }
 
-      if (val == null) {
+      // default
-        val = clone(option.default);
+      if (val == null) val = clone(option.default);
-      }
 
-      var optionParser = optionParsers[option.type];
+      // validate
-      if (optionParser) val = optionParser(key, val, this.pipeline);
+      if (val) val = validateOption(key, val, this.pipeline);
 
+      // aaliases
       if (option.alias) {
         opts[option.alias] = opts[option.alias] || val;
       } else {
@@ -152,7 +166,10 @@ export default class File {
     opts.basename = path.basename(opts.filename, path.extname(opts.filename));
 
     opts.ignore = util.arrayify(opts.ignore, util.regexify);
-    opts.only   = util.arrayify(opts.only, util.regexify);
+
+    if (opts.only) {
+      opts.only = util.arrayify(opts.only, util.regexify);
+    }
 
     defaults(opts, {
       moduleRoot: opts.sourceRoot
@@ -168,7 +185,7 @@ export default class File {
 
     defaults(opts, {
       sourceFileName: opts.filenameRelative,
-      sourceMapName:  opts.filenameRelative
+      sourceMapTarget:  opts.filenameRelative
     });
 
     //
@@ -195,7 +212,7 @@ export default class File {
     // build internal transformers
     for (var key in this.pipeline.transformers) {
       var transformer = this.pipeline.transformers[key];
-      var pass = transformers[key] = transformer.buildPass(file);
+      let pass = transformers[key] = transformer.buildPass(file);
 
       if (pass.canTransform()) {
         stack.push(pass);
@@ -228,8 +245,8 @@ export default class File {
     this.uncollapsedTransformerStack = stack = stack.concat(secondaryStack);
 
     // build dependency graph
-    for (var pass of (stack: Array)) {
+    for (let pass of (stack: Array)) {
-      for (var dep of (pass.transformer.dependencies: Array)) {
+      for (var dep of (pass.plugin.dependencies: Array)) {
         this.transformerDependencies[dep] = pass.key;
       }
     }
@@ -246,7 +263,7 @@ export default class File {
       // been merged
       if (ignore.indexOf(pass) >= 0) continue;
 
-      var group = pass.transformer.metadata.group;
+      var group = pass.plugin.metadata.group;
 
       // can't merge
       if (!pass.canTransform() || !group) {
@@ -256,7 +273,7 @@ export default class File {
 
       var mergeStack = [];
       for (let pass of (_stack: Array)) {
-        if (pass.transformer.metadata.group === group) {
+        if (pass.plugin.metadata.group === group) {
           mergeStack.push(pass);
           ignore.push(pass);
         }
@@ -264,12 +281,11 @@ export default class File {
 
       var visitors = [];
       for (let pass of (mergeStack: Array)) {
-        visitors.push(pass.handlers);
+        visitors.push(pass.plugin.visitor);
       }
       var visitor = traverse.visitors.merge(visitors);
-      var mergeTransformer = new Transformer(group, visitor);
+      var mergePlugin = new Plugin(group, { visitor });
-      //console.log(mergeTransformer);
+      stack.push(mergePlugin.buildPass(this));
-      stack.push(mergeTransformer.buildPass(this));
     }
 
     return stack;
@@ -319,7 +335,7 @@ export default class File {
       }
 
       if (this.transformers["es6.modules"].canTransform()) {
-        this.moduleFormatter.importSpecifier(specifiers[0], declar, this.dynamicImports);
+        this.moduleFormatter.importSpecifier(specifiers[0], declar, this.dynamicImports, this.scope);
         this.moduleFormatter.hasLocalImports = true;
       } else {
         this.dynamicImports.push(declar);
@@ -330,14 +346,24 @@ export default class File {
   }
 
   attachAuxiliaryComment(node: Object): Object {
-    var comment = this.opts.auxiliaryComment;
+    var beforeComment = this.opts.auxiliaryCommentBefore;
-    if (comment) {
+    if (beforeComment) {
       node.leadingComments = node.leadingComments || [];
       node.leadingComments.push({
-        type: "Line",
+        type: "CommentLine",
-        value: " " + comment
+        value: " " + beforeComment
       });
     }
+
+    var afterComment = this.opts.auxiliaryCommentAfter;
+    if (afterComment) {
+      node.trailingComments = node.trailingComments || [];
+      node.trailingComments.push({
+        type: "CommentLine",
+        value: " " + afterComment
+      });
+    }
+
     return node;
   }
 
@@ -348,8 +374,6 @@ export default class File {
       throw new ReferenceError(`Unknown helper ${name}`);
     }
 
-    var program = this.ast.program;
-
     var declar = this.declarations[name];
     if (declar) return declar;
 
@@ -390,9 +414,15 @@ export default class File {
   }
 
   errorWithNode(node, msg, Error = SyntaxError) {
-    var loc = node.loc.start;
+    var err;
-    var err = new Error(`Line ${loc.line}: ${msg}`);
+    if (node && node.loc) {
-    err.loc = loc;
+      var loc = node.loc.start;
+      err = new Error(`Line ${loc.line}: ${msg}`);
+      err.loc = loc;
+    } else {
+      // todo: find errors with nodes inside to at least point to something
+      err = new Error("There's been an error on a dynamic node. This is almost certainly an internal error. Please report it.");
+    }
     return err;
   }
 
@@ -410,7 +440,7 @@ export default class File {
       outputMapGenerator.applySourceMap(inputMapConsumer);
 
       var mergedMap = outputMapGenerator.toJSON();
-      mergedMap.sources = inputMap.sources
+      mergedMap.sources = inputMap.sources;
       mergedMap.file    = inputMap.file;
       return mergedMap;
     }
@@ -420,6 +450,10 @@ export default class File {
 
 
   getModuleFormatter(type: string) {
+    if (isFunction(type) || !moduleFormatters[type]) {
+      this.log.deprecate("Custom module formatters are deprecated and will be removed in the next major. Please use Babel plugins instead.");
+    }
+
     var ModuleFormatter = isFunction(type) ? type : moduleFormatters[type];
 
     if (!ModuleFormatter) {
@@ -463,7 +497,13 @@ export default class File {
   }
 
   _addAst(ast) {
-    this.path  = TraversalPath.get(null, null, ast, ast, "program", this);
+    this.path = NodePath.get({
+      hub: this.hub,
+      parentPath: null,
+      parent: ast,
+      container: ast,
+      key: "program"
+    }).setContext();
     this.scope = this.path.scope;
     this.ast   = ast;
   }
@@ -479,12 +519,16 @@ export default class File {
       modFormatter.init();
     }
     this.log.debug("End module formatter init");
+  }
 
+  transform() {
     this.call("pre");
     for (var pass of (this.transformerStack: Array)) {
       pass.transform();
     }
     this.call("post");
+
+    return this.generate();
   }
 
   wrap(code, callback) {
@@ -492,18 +536,10 @@ export default class File {
 
     try {
       if (this.shouldIgnore()) {
-        return {
+        return this.makeResult({ code, ignored: true });
-          metadata: this.metadata,
+      } else {
-          ignored:  true,
+        return callback();
-          code:     code,
-          map:      null,
-          ast:      null
-        };
       }
-
-      callback();
-
-      return this.generate();
     } catch (err) {
       if (err._babel) {
         throw err;
@@ -532,15 +568,15 @@ export default class File {
     }
   }
 
-  addCode(code: string, parseCode?) {
+  addCode(code: string) {
     code = (code || "") + "";
     code = this.parseInputSourceMap(code);
     this.code = code;
+  }
 
-    if (parseCode) {
+  parseCode() {
-      this.parseShebang();
+    this.parseShebang();
-      this.addAst(this.parse(this.code));
+    this.addAst(this.parse(this.code));
-    }
   }
 
   shouldIgnore() {
@@ -550,7 +586,7 @@ export default class File {
 
   call(key: string) {
     for (var pass of (this.uncollapsedTransformerStack: Array)) {
-      var fn = pass.transformer[key];
+      var fn = pass.plugin[key];
       if (fn) fn(this);
     }
   }
@@ -577,28 +613,37 @@ export default class File {
     }
   }
 
-  generate(): {
+  makeResult({ code, map = null, ast, ignored }) {
-    usedHelpers?: Array<string>;
-    code: string;
-    map?: Object;
-    ast?: Object;
-  } {
-    var opts = this.opts;
-    var ast  = this.ast;
-
     var result = {
-      metadata: this.metadata,
+      metadata: null,
-      code:     "",
+      ignored:  !!ignored,
-      map:      null,
+      code:     null,
-      ast:      null
+      ast:      null,
+      map:      map
     };
 
-    if (this.opts.metadataUsedHelpers) {
+    if (this.opts.code) {
+      result.code = code;
+    }
+
+    if (this.opts.ast) {
+      result.ast = ast;
+    }
+
+    if (this.opts.metadata) {
+      result.metadata = this.metadata;
       result.metadata.usedHelpers = Object.keys(this.usedHelpers);
     }
 
-    if (opts.ast) result.ast = ast;
+    return result;
-    if (!opts.code) return result;
+  }
+
+  generate() {
+    var opts = this.opts;
+    var ast  = this.ast;
+
+    var result = { ast };
+    if (!opts.code) return this.makeResult(result);
 
     this.log.debug("Generation start");
 
@@ -625,6 +670,6 @@ export default class File {
       result.map = null;
     }
 
-    return result;
+    return this.makeResult(result);
   }
 }

src/babel/transformation/file/logger.js

@@ -1,8 +1,11 @@
+import type File from "./index";
 import buildDebug from "debug/node";
 
 var verboseDebug = buildDebug("babel:verbose");
 var generalDebug = buildDebug("babel");
 
+var seenDeprecatedMessages = [];
+
 export default class Logger {
   constructor(file: File, filename: string) {
     this.filename = filename;
@@ -15,14 +18,26 @@ export default class Logger {
     return parts;
   }
 
+  warn(msg) {
+    console.warn(this._buildMessage(msg));
+  }
+
   error(msg: string, Constructor = Error) {
     throw new Constructor(this._buildMessage(msg));
   }
 
   deprecate(msg) {
-    if (!this.file.opts.suppressDeprecationMessages) {
+    if (this.file.opts.suppressDeprecationMessages) return;
-      console.error(this._buildMessage(msg));
+
-    }
+    msg = this._buildMessage(msg);
+
+    // already seen this message
+    if (seenDeprecatedMessages.indexOf(msg) >= 0) return;
+
+    // make sure we don't see it again
+    seenDeprecatedMessages.push(msg);
+
+    console.error(msg);
   }
 
   verbose(msg: string) {

src/babel/transformation/file/option-parsers.js

@@ -1,27 +0,0 @@
-import * as util from  "../../util";
-
-export function transformerList(key, val, pipeline) {
-  val = util.arrayify(val);
-
-  if (val.indexOf("all") >= 0 || val.indexOf(true) >= 0) {
-    val = Object.keys(pipeline.transformers);
-  }
-
-  return pipeline._ensureTransformerNames(key, val);
-}
-
-export function number(key, val) {
-  return +val;
-}
-
-export function boolean(key, val) {
-  return !!val;
-}
-
-export function booleanString(key, val) {
-  return util.booleanify(val);
-}
-
-export function list(key, val) {
-  return util.list(val);
-}

src/babel/transformation/file/options/config.json

@@ -43,15 +43,17 @@
   "nonStandard": {
     "type": "boolean",
     "default": true,
-    "description": "enable support for JSX and Flow"
+    "description": "enable/disable support for JSX and Flow (on by default)"
   },
 
   "experimental": {
-    "deprecated": "use `--stage 0`/`{ stage: 0 }` instead"
+    "type": "boolean",
+    "description": "allow use of experimental transformers",
+    "default": false
   },
 
   "highlightCode": {
-    "description": "ANSI syntax highlight code frames",
+    "description": "enable/disable ANSI syntax highlighting of code frames (on by default)",
     "type": "boolean",
     "default": true
   },
@@ -76,7 +78,8 @@
   "blacklist": {
     "type": "transformerList",
     "description": "blacklist of transformers to NOT use",
-    "shorthand": "b"
+    "shorthand": "b",
+    "default": []
   },
 
   "whitelist": {
@@ -88,7 +91,8 @@
 
   "optional": {
     "type": "transformerList",
-    "description": "list of optional transformers to enable"
+    "description": "list of optional transformers to enable",
+    "default": []
   },
 
   "modules": {
@@ -120,12 +124,14 @@
 
   "plugins": {
     "type": "list",
-    "description": ""
+    "description": "",
+    "default": []
   },
 
   "ignore": {
     "type": "list",
-    "description": "list of glob paths to **not** compile"
+    "description": "list of glob paths to **not** compile",
+    "default": []
   },
 
   "only": {
@@ -139,6 +145,12 @@
     "type": "boolean"
   },
 
+  "metadata": {
+    "hidden": true,
+    "default": true,
+    "type": "boolean"
+  },
+
   "ast": {
     "hidden": true,
     "default": true,
@@ -148,7 +160,7 @@
   "comments": {
     "type": "boolean",
     "default": true,
-    "description": "output comments in generated output"
+    "description": "strip/output comments in generated output (on by default)"
   },
 
   "compact": {
@@ -165,12 +177,23 @@
   },
 
   "auxiliaryComment": {
+    "deprecated": "renamed to auxiliaryCommentBefore",
+    "shorthand": "a",
+    "alias": "auxiliaryCommentBefore"
+  },
+
+  "auxiliaryCommentBefore": {
     "type": "string",
     "default": "",
-    "shorthand": "a",
     "description": "attach a comment before all helper declarations and auxiliary code"
   },
 
+  "auxiliaryCommentAfter": {
+    "type": "string",
+    "default": "",
+    "description": "attach a comment after all helper declarations and auxiliary code"
+  },
+
   "externalHelpers": {
     "type": "boolean",
     "default": false,
@@ -179,6 +202,7 @@
   },
 
   "metadataUsedHelpers": {
+    "deprecated": "Not required anymore as this is enabled by default",
     "type": "boolean",
     "default": false,
     "hidden": true
@@ -197,6 +221,11 @@
   },
 
   "sourceMapName": {
+    "alias": "sourceMapTarget",
+    "description": "DEPRECATED - Please use sourceMapTarget"
+  },
+
+  "sourceMapTarget": {
     "type": "string",
     "description": "set `file` on returned source map"
   },

src/babel/transformation/file/options/index.js

@@ -0,0 +1,31 @@
+import * as parsers from "./parsers";
+import config from "./config";
+
+export { config };
+
+export function validateOption(key, val, pipeline) {
+  var opt = config[key];
+  var parser = opt && parsers[opt.type];
+  if (parser && parser.validate) {
+    return parser.validate(key, val, pipeline);
+  } else {
+    return val;
+  }
+}
+
+export function normaliseOptions(options = {}) {
+  for (var key in options) {
+    var val = options[key];
+    if (val == null) continue;
+
+    var opt = config[key];
+    if (!opt) continue;
+
+    var parser = parsers[opt.type];
+    if (parser) val = parser(val);
+
+    options[key] = val;
+  }
+
+  return options;
+}

src/babel/transformation/file/options/parsers.js

@@ -0,0 +1,29 @@
+import * as util from "../../../util";
+
+export function transformerList(val) {
+  return util.arrayify(val);
+}
+
+transformerList.validate = function (key, val, pipeline) {
+  if (val.indexOf("all") >= 0 || val.indexOf(true) >= 0) {
+    val = Object.keys(pipeline.transformers);
+  }
+
+  return pipeline._ensureTransformerNames(key, val);
+};
+
+export function number(val) {
+  return +val;
+}
+
+export function boolean(val) {
+  return !!val;
+}
+
+export function booleanString(val) {
+  return util.booleanify(val);
+}
+
+export function list(val) {
+  return util.list(val);
+}

src/babel/transformation/file/options/resolve-rc.js

@@ -1,17 +1,17 @@
 import stripJsonComments from "strip-json-comments";
-import merge from "../helpers/merge";
+import { normaliseOptions } from "./index";
+import merge from "../../../helpers/merge";
 import path from "path";
 import fs from "fs";
+import pathExists from "path-exists";
 
 var cache = {};
 var jsons = {};
 
 function exists(filename) {
-  if (!fs.existsSync) return false;
-
   var cached = cache[filename];
   if (cached != null) return cached;
-  return cache[filename] = fs.existsSync(filename);
+  return cache[filename] = pathExists.sync(filename);
 }
 
 export default function (loc, opts = {}) {
@@ -34,6 +34,7 @@ export default function (loc, opts = {}) {
 
       try {
         json = jsons[content] = jsons[content] || JSON.parse(stripJsonComments(content));
+        normaliseOptions(json);
       } catch (err) {
         err.message = `${file}: ${err.message}`;
         throw err;
@@ -42,6 +43,7 @@ export default function (loc, opts = {}) {
       opts.babelrc.push(file);
 
       if (json.breakConfig) return;
+
       merge(opts, json);
     }
 
@@ -56,4 +58,4 @@ export default function (loc, opts = {}) {
   }
 
   return opts;
-};
+}

src/babel/transformation/file/plugin-manager.js

@@ -1,5 +1,19 @@
-import * as node from  "../../api/node";
+import Transformer from "../transformer";
+import Plugin from "../plugin";
+import * as types from "../../types";
 import * as messages from "../../messages";
+import traverse from "../../types";
+import parse from "../../helpers/parse";
+
+var context = {
+  messages,
+  Transformer,
+  Plugin,
+  types,
+  parse,
+  traverse
+};
+
 import * as util from  "../../util";
 
 export default class PluginManager {
@@ -11,7 +25,7 @@ export default class PluginManager {
       if (plugin.container === fn) return plugin.transformer;
     }
 
-    var transformer = fn(node);
+    var transformer = fn(context);
     PluginManager.memoisedPlugins.push({
       container: fn,
       transformer: transformer
@@ -35,11 +49,12 @@ export default class PluginManager {
     var match = name.match(/^(.*?):(after|before)$/);
     if (match) [, name, position] = match;
 
-    var loc = util.resolveRelative(name) || util.resolveRelative(`babel-plugin-${name}`);
+    var loc = util.resolveRelative(`babel-plugin-${name}`) || util.resolveRelative(name);
     if (loc) {
+      var plugin = require(loc);
       return {
         position: position,
-        plugin:   require(loc)
+        plugin:   plugin.default || plugin
       };
     } else {
       throw new ReferenceError(messages.get("pluginUnknown", name));
@@ -54,7 +69,7 @@ export default class PluginManager {
     }
 
     // validate Transformer instance
-    if (!plugin.buildPass || plugin.constructor.name !== "Transformer") {
+    if (!plugin.buildPass || plugin.constructor.name !== "Plugin") {
       throw new TypeError(messages.get("pluginNotTransformer", name));
     }
 

src/babel/transformation/helpers/build-binary-assignment-operator-transformer.js

@@ -44,4 +44,4 @@ export default function (opts) {
   };
 
   return exports;
-};
+}

src/babel/transformation/helpers/build-conditional-assignment-operator-transformer.js

@@ -42,4 +42,4 @@ export default function (exports, opts) {
 
     return nodes;
   };
-};
+}

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

@@ -9,8 +9,10 @@ import esutils from "esutils";
 import * as react from "./react";
 import * as t from "../../types";
 
-export default function (exports, opts) {
+export default function (opts) {
-  exports.JSXIdentifier = function (node, parent) {
+  var visitor = {};
+
+  visitor.JSXIdentifier = function (node) {
     if (node.name === "this" && this.isReferenced()) {
       return t.thisExpression();
     } else if (esutils.keyword.isIdentifierNameES6(node.name)) {
@@ -20,22 +22,22 @@ export default function (exports, opts) {
     }
   };
 
-  exports.JSXNamespacedName = function (node, parent, scope, file) {
+  visitor.JSXNamespacedName = function () {
     throw this.errorWithNode(messages.get("JSXNamespacedTags"));
   };
 
-  exports.JSXMemberExpression = {
+  visitor.JSXMemberExpression = {
     exit(node) {
       node.computed = t.isLiteral(node.property);
       node.type = "MemberExpression";
     }
   };
 
-  exports.JSXExpressionContainer = function (node) {
+  visitor.JSXExpressionContainer = function (node) {
     return node.expression;
   };
 
-  exports.JSXAttribute = {
+  visitor.JSXAttribute = {
     enter(node) {
       var value = node.value;
       if (t.isLiteral(value) && isString(value.value)) {
@@ -49,7 +51,7 @@ export default function (exports, opts) {
     }
   };
 
-  exports.JSXOpeningElement = {
+  visitor.JSXOpeningElement = {
     exit(node, parent, scope, file) {
       parent.children = react.buildChildren(parent);
 
@@ -139,7 +141,7 @@ export default function (exports, opts) {
     return attribs;
   };
 
-  exports.JSXElement = {
+  visitor.JSXElement = {
     exit(node) {
       var callExpr = node.openingElement;
 
@@ -153,53 +155,5 @@ export default function (exports, opts) {
     }
   };
 
-  // display names
+  return visitor;
-
+}
-  var addDisplayName = function (id, call) {
-    var props = call.arguments[0].properties;
-    var safe = true;
-
-    for (var i = 0; i < props.length; i++) {
-      var prop = props[i];
-      if (t.isIdentifier(prop.key, { name: "displayName" })) {
-        safe = false;
-        break;
-      }
-    }
-
-    if (safe) {
-      props.unshift(t.property("init", t.identifier("displayName"), t.literal(id)));
-    }
-  };
-
-  exports.ExportDefaultDeclaration = function (node, parent, scope, file) {
-    if (react.isCreateClass(node.declaration)) {
-      addDisplayName(file.opts.basename, node.declaration);
-    }
-  };
-
-  exports.AssignmentExpression =
-  exports.Property =
-  exports.VariableDeclarator = function (node) {
-    var left, right;
-
-    if (t.isAssignmentExpression(node)) {
-      left = node.left;
-      right = node.right;
-    } else if (t.isProperty(node)) {
-      left = node.key;
-      right = node.value;
-    } else if (t.isVariableDeclarator(node)) {
-      left = node.id;
-      right = node.init;
-    }
-
-    if (t.isMemberExpression(left)) {
-      left = left.property;
-    }
-
-    if (t.isIdentifier(left) && react.isCreateClass(right)) {
-      addDisplayName(left.name, right);
-    }
-  };
-};

src/babel/transformation/helpers/call-delegate.js

@@ -1,4 +1,3 @@
-import traverse from "../../traversal";
 import * as t from "../../types";
 
 var visitor = {
@@ -7,10 +6,10 @@ var visitor = {
       state.found = true;
       this.stop();
     }
+  },
 
-    if (this.isFunction()) {
+  Function() {
-      this.skip();
+    this.skip();
-    }
   }
 };
 

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

@@ -1,5 +1,3 @@
-import cloneDeep from "lodash/lang/cloneDeep";
-import traverse from "../../traversal";
 import each from "lodash/collection/each";
 import has from "lodash/object/has";
 import * as t from "../../types";

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

@@ -68,4 +68,4 @@ export default function (node, nodes, file, scope, allowedSingleIdent) {
     uid: uid,
     ref: ref
   };
-};
+}

src/babel/transformation/helpers/get-function-arity.js

@@ -3,7 +3,10 @@ import * as t from "../../types";
 export default function (node) {
   var lastNonDefault = 0;
   for (var i = 0; i < node.params.length; i++) {
-    if (!t.isAssignmentPattern(node.params[i])) lastNonDefault = i + 1;
+    var param = node.params[i];
+    if (!t.isAssignmentPattern(param) && !t.isRestElement(param)) {
+      lastNonDefault = i + 1;
+    }
   }
   return lastNonDefault;
-};
+}

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

@@ -2,25 +2,32 @@ import getFunctionArity from "./get-function-arity";
 import * as util from  "../../util";
 import * as t from "../../types";
 
+function visitIdentifier(context, node, scope, state) {
+  // check if this node matches our function id
+  if (node.name !== state.name) return;
+
+  // check that we don't have a local variable declared as that removes the need
+  // for the wrapper
+  var localDeclar = scope.getBindingIdentifier(state.name);
+  if (localDeclar !== state.outerDeclar) return;
+
+  state.selfReference = true;
+  context.stop();
+}
+
 var visitor = {
-  enter(node, parent, scope, state) {
+  ReferencedIdentifier(node, parent, scope, state) {
-    // check if this node is a referenced identifier that matches the same as our
+    visitIdentifier(this, node, scope, state);
-    // function id
+  },
-    if (!this.isReferencedIdentifier({ name: state.name })) return;
 
-    // check that we don't have a local variable declared as that removes the need
+  BindingIdentifier(node, parent, scope, state) {
-    // for the wrapper
+    visitIdentifier(this, node, scope, state);
-    var localDeclar = scope.getBindingIdentifier(state.name);
-    if (localDeclar !== state.outerDeclar) return;
-
-    state.selfReference = true;
-    this.stop();
   }
 };
 
 var wrap = function (state, method, id, scope) {
   if (state.selfReference) {
-    if (scope.hasBinding(id.name)) {
+    if (scope.hasBinding(id.name) && !scope.hasGlobal(id.name)) {
       // we can just munge the local binding
       scope.rename(id.name);
     } else {
@@ -46,6 +53,7 @@ var wrap = function (state, method, id, scope) {
   }
 
   method.id = id;
+  scope.getProgramParent().references[id.name] = true;
 };
 
 var visit = function (node, name, scope) {
@@ -60,10 +68,10 @@ var visit = function (node, name, scope) {
   // check to see if we have a local binding of the id we're setting inside of
   // the function, this is important as there are caveats associated
 
-  var bindingInfo = scope.getOwnBindingInfo(name);
+  var binding = scope.getOwnBinding(name);
 
-  if (bindingInfo) {
+  if (binding) {
-    if (bindingInfo.kind === "param") {
+    if (binding.kind === "param") {
       // safari will blow up in strict mode with code like:
       //
       //   var t = function t(t) {};
@@ -103,8 +111,7 @@ export function property(node, file, scope) {
   var key = t.toComputedKey(node, node.key);
   if (!t.isLiteral(key)) return; // we can't set a function id with this
 
-  var name = t.toIdentifier(key.value);
+  var name = t.toBindingIdentifierName(key.value);
-  if (name === "eval" || name === "arguments") name = "_" + name;
   var id = t.identifier(name);
 
   var method = node.value;
@@ -125,8 +132,8 @@ export function bare(node, parent, scope) {
     id = parent.id;
 
     if (t.isIdentifier(id)) {
-      var bindingInfo = scope.parent.getBinding(id.name);
+      var binding = scope.parent.getBinding(id.name);
-      if (bindingInfo && bindingInfo.constant && scope.getBinding(id.name) === bindingInfo) {
+      if (binding && binding.constant && scope.getBinding(id.name) === binding) {
         // always going to reference this method
         node.id = id;
         return;
@@ -145,7 +152,7 @@ export function bare(node, parent, scope) {
     return;
   }
 
-  name = t.toIdentifier(name);
+  name = t.toBindingIdentifierName(name);
   id = t.identifier(name);
 
   var state = visit(node, name, scope);

src/babel/transformation/helpers/react.js

@@ -1,35 +1,11 @@
-import isString from "lodash/lang/isString";
 import * as t from "../../types";
 
-var isCreateClassCallExpression = t.buildMatchMemberExpression("React.createClass");
-
-export function isCreateClass(node) {
-  if (!node || !t.isCallExpression(node)) return false;
-
-  // not React.createClass call member object
-  if (!isCreateClassCallExpression(node.callee)) return false;
-
-  // no call arguments
-  var args = node.arguments;
-  if (args.length !== 1) return false;
-
-  // first node arg is not an object
-  var first = args[0];
-  if (!t.isObjectExpression(first)) return false;
-
-  return true;
-}
-
 export var isReactComponent = t.buildMatchMemberExpression("React.Component");
 
 export function isCompatTag(tagName) {
   return tagName && /^[a-z]|\-/.test(tagName);
 }
 
-function isStringLiteral(node) {
-  return t.isLiteral(node) && isString(node.value);
-}
-
 function cleanJSXElementLiteralChild(child, args) {
   var lines = child.value.split(/\r\n|\n|\r/);
 

src/babel/transformation/helpers/remap-async-to-generator.js

@@ -1,35 +1,37 @@
 import * as t from "../../types";
 
 var awaitVisitor = {
-  enter(node, parent, scope, state) {
+  Function() {
-    if (t.isFunction(node)) this.skip();
+    this.skip();
+  },
 
-    if (t.isAwaitExpression(node)) {
+  AwaitExpression(node) {
-      node.type = "YieldExpression";
+    node.type = "YieldExpression";
 
-      if (node.all) {
+    if (node.all) {
-        // await* foo; -> yield Promise.all(foo);
+      // await* foo; -> yield Promise.all(foo);
-        node.all = false;
+      node.all = false;
-        node.argument = t.callExpression(t.memberExpression(t.identifier("Promise"), t.identifier("all")), [node.argument]);
+      node.argument = t.callExpression(t.memberExpression(t.identifier("Promise"), t.identifier("all")), [node.argument]);
-      }
     }
   }
 };
 
 var referenceVisitor = {
-  enter(node, parent, scope, state) {
+  ReferencedIdentifier(node, parent, scope, state) {
     var name = state.id.name;
-    if (this.isReferencedIdentifier({ name: name }) && scope.bindingIdentifierEquals(name, state.id)) {
+    if (node.name === name && scope.bindingIdentifierEquals(name, state.id)) {
       return state.ref = state.ref || scope.generateUidIdentifier(name);
     }
   }
 };
 
-export default function (node, callId, scope) {
+export default function (path, callId) {
+  var node = path.node;
+
   node.async = false;
   node.generator = true;
 
-  scope.traverse(node, awaitVisitor, state);
+  path.traverse(awaitVisitor, state);
 
   var call = t.callExpression(callId, [node]);
 
@@ -44,15 +46,15 @@ export default function (node, callId, scope) {
     return declar;
   } else {
     if (id) {
-      var state = { id: id };
+      var state = { id };
-      scope.traverse(node, referenceVisitor, state);
+      path.traverse(referenceVisitor, state);
 
       if (state.ref) {
-        scope.parent.push({ id: state.ref });
+        path.scope.parent.push({ id: state.ref });
         return t.assignmentExpression("=", state.ref, call);
       }
     }
 
     return call;
   }
-};
+}

src/babel/transformation/helpers/replace-supers.js

@@ -1,3 +1,4 @@
+import type NodePath from "../../traversal/path";
 import * as messages from "../../messages";
 import * as t from "../../types";
 
@@ -130,7 +131,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  traverseLevel(path: TraversalPath, topLevel: boolean) {
+  traverseLevel(path: NodePath, topLevel: boolean) {
     var state = { self: this, topLevel: topLevel };
     path.traverse(visitor, state);
   }
@@ -168,7 +169,13 @@ export default class ReplaceSupers {
 
       if (methodName.name === "constructor") {
         // constructor() { super(); }
-        return t.memberExpression(superRef, t.identifier("call"));
+        if (parent.arguments.length === 2 && t.isSpreadElement(parent.arguments[1]) && t.isIdentifier(parent.arguments[1].argument, { name: "arguments" })) {
+          // special case single arguments spread
+          parent.arguments[1] = parent.arguments[1].argument;
+          return t.memberExpression(superRef, t.identifier("apply"));
+        } else {
+          return t.memberExpression(superRef, t.identifier("call"));
+        }
       } else {
         id = superRef;
 
@@ -192,7 +199,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  looseHandle(path: TraversalPath, getThisReference: Function) {
+  looseHandle(path: NodePath, getThisReference: Function) {
     var node = path.node;
     if (path.isSuper()) {
       return this.getLooseSuperProperty(node, path.parent);
@@ -234,7 +241,7 @@ export default class ReplaceSupers {
    * Description
    */
 
-  specHandle(path: TraversalPath, getThisReference: Function) {
+  specHandle(path: NodePath, getThisReference: Function) {
     var methodNode = this.methodNode;
     var property;
     var computed;
@@ -274,7 +281,7 @@ export default class ReplaceSupers {
       property = node.property;
       computed = node.computed;
     } else if (t.isUpdateExpression(node) && isMemberExpressionSuper(node.argument)) {
-      var binary = t.binaryExpression(node.operator[0], node.argument, t.literal(1))
+      var binary = t.binaryExpression(node.operator[0], node.argument, t.literal(1));
       if (node.prefix) {
         // ++super.foo; -> super.foo += 1;
         return this.specHandleAssignmentExpression(null, path, binary, getThisReference);

src/babel/transformation/helpers/strict.js

@@ -1,19 +0,0 @@
-import * as t from "../../types";
-
-export function has(node) {
-  var first = node.body[0];
-  return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
-}
-
-export function wrap(node, callback) {
-  var useStrictNode;
-  if (has(node)) {
-    useStrictNode = node.body.shift();
-  }
-
-  callback();
-
-  if (useStrictNode) {
-    node.body.unshift(useStrictNode);
-  }
-}

src/babel/transformation/index.js

@@ -1,4 +1,4 @@
-import Pipeline from "./transformer-pipeline";
+import Pipeline from "./pipeline";
 
 var pipeline = new Pipeline;
 
@@ -8,8 +8,11 @@ import transformers from "./transformers";
 
 for (var key in transformers) {
   var transformer = transformers[key];
-  var metadata = transformer.metadata = transformer.metadata || {};
+
-  metadata.group = metadata.group || "builtin-basic";
+  if (typeof transformer === "object") {
+    var metadata = transformer.metadata = transformer.metadata || {};
+    metadata.group = metadata.group || "builtin-basic";
+  }
 }
 
 pipeline.addTransformers(transformers);

src/babel/transformation/modules/_default.js

@@ -1,124 +1,182 @@
 import * as messages from "../../messages";
-import traverse from "../../traversal";
+import Remaps from "./lib/remaps";
 import extend from "lodash/object/extend";
 import object from "../../helpers/object";
 import * as util from  "../../util";
 import * as t from "../../types";
 
-var remapVisitor = {
+var metadataVisitor = {
-  enter(node, parent, scope, formatter) {
+  ModuleDeclaration: {
-    if (node._skipModulesRemap) {
+    enter(node, parent, scope, formatter) {
-      return this.skip();
+      if (node.source) {
-    }
+        node.source.value = formatter.file.resolveModuleSource(node.source.value);
-  },
+        formatter.addScope(this);
-
-  ReferencedIdentifier(node, parent, scope, formatter) {
-    var remap = formatter.internalRemap[node.name];
-
-    if (remap && node !== remap) {
-      if (!scope.hasBinding(node.name) || scope.bindingIdentifierEquals(node.name, formatter.localImports[node.name])) {
-        if (this.key === "callee" && this.parentPath.isCallExpression()) {
-          return t.sequenceExpression([t.literal(0), remap]);
-        } else {
-          return remap;
-        }
       }
     }
   },
 
-  AssignmentExpression: {
-    exit(node, parent, scope, formatter) {
-      if (!node._ignoreModulesRemap) {
-        var exported = formatter.getExport(node.left, scope);
-        if (exported) {
-          return formatter.remapExportAssignment(node, exported);
-        }
-      }
-    }
-  },
-
-  UpdateExpression(node, parent, scope, formatter) {
-    var exported = formatter.getExport(node.argument, scope);
-    if (!exported) return;
-
-    this.skip();
-
-    // expand to long file assignment expression
-    var assign = t.assignmentExpression(node.operator[0] + "=", node.argument, t.literal(1));
-
-    // remap this assignment expression
-    var remapped = formatter.remapExportAssignment(assign, exported);
-
-    // we don't need to change the result
-    if (t.isExpressionStatement(parent) || node.prefix) {
-      return remapped;
-    }
-
-    var nodes = [];
-    nodes.push(remapped);
-
-    var operator;
-    if (node.operator === "--") {
-      operator = "+";
-    } else { // "++"
-      operator = "-";
-    }
-    nodes.push(t.binaryExpression(operator, node.argument, t.literal(1)));
-
-    return t.sequenceExpression(nodes);
-  }
-};
-
-var importsVisitor = {
   ImportDeclaration: {
-    enter(node, parent, scope, formatter) {
+    exit(node, parent, scope, formatter) {
       formatter.hasLocalImports = true;
-      extend(formatter.localImports, this.getBindingIdentifiers());
+
+      var specifiers = [];
+      var imported = [];
+      formatter.metadata.imports.push({
+        source: node.source.value,
+        imported,
+        specifiers
+      });
+
+      for (var specifier of (this.get("specifiers"): Array)) {
+        var ids = specifier.getBindingIdentifiers();
+        extend(formatter.localImports, ids);
+
+        var local = specifier.node.local.name;
+
+        if (specifier.isImportDefaultSpecifier()) {
+          imported.push("default");
+          specifiers.push({
+            kind: "named",
+            imported: "default",
+            local
+          });
+        }
+
+        if (specifier.isImportSpecifier()) {
+          var importedName = specifier.node.imported.name;
+          imported.push(importedName);
+          specifiers.push({
+            kind: "named",
+            imported: importedName,
+            local
+          });
+        }
+
+        if (specifier.isImportNamespaceSpecifier()) {
+          imported.push("*");
+          specifiers.push({
+            kind: "namespace",
+            local
+          });
+        }
+      }
     }
-  }
+  },
-};
 
-var exportsVisitor = {
+  ExportDeclaration(node, parent, scope, formatter) {
-  ExportDeclaration: {
+    formatter.hasLocalExports = true;
-    enter(node, parent, scope, formatter) {
-      formatter.hasLocalExports = true;
 
-      var declar = this.get("declaration");
+    var source = node.source ? node.source.value : null;
-      if (declar.isStatement()) {
+    var exports = formatter.metadata.exports;
-        var bindings = declar.getBindingIdentifiers()
+
-        for (var name in bindings) {
+    // export function foo() {}
-          var binding = bindings[name];
+    // export var foo = "bar";
-          formatter._addExport(name, binding);
+    var declar = this.get("declaration");
+    if (declar.isStatement()) {
+      var bindings = declar.getBindingIdentifiers();
+
+      for (var name in bindings) {
+        var binding = bindings[name];
+        formatter._addExport(name, binding);
+
+        exports.exported.push(name);
+        exports.specifiers.push({
+          kind: "local",
+          local: name,
+          exported: this.isExportDefaultDeclaration() ? "default" : name
+        });
+      }
+    }
+
+    if (this.isExportNamedDeclaration() && node.specifiers) {
+      for (var specifier of (node.specifiers: Array)) {
+        var exported = specifier.exported.name;
+        exports.exported.push(exported);
+
+        // export foo from "bar";
+        if (t.isExportDefaultSpecifier(specifier)) {
+          exports.specifiers.push({
+            kind: "external",
+            local: exported,
+            exported,
+            source
+          });
+        }
+
+        // export * as foo from "bar";
+        if (t.isExportNamespaceSpecifier(specifier)) {
+          exports.specifiers.push({
+            kind: "external-namespace",
+            exported,
+            source
+          });
+        }
+
+        var local = specifier.local;
+        if (!local) continue;
+
+        formatter._addExport(local.name, specifier.exported);
+
+        // export { foo } from "bar";
+        // export { foo as bar } from "bar";
+        if (source) {
+          exports.specifiers.push({
+            kind: "external",
+            local: local.name,
+            exported,
+            source
+          });
+        }
+
+        // export { foo };
+        // export { foo as bar };
+        if (!source) {
+          exports.specifiers.push({
+            kind: "local",
+            local: local.name,
+            exported
+          });
         }
       }
+    }
 
-      if (this.isExportNamedDeclaration() && node.specifiers) {
+    // export * from "bar";
-        for (var i = 0; i < node.specifiers.length; i++) {
+    if (this.isExportAllDeclaration()) {
-          var specifier = node.specifiers[i];
+      exports.specifiers.push({
-          var local = specifier.local;
+        kind: "external-all",
-          if (!local) continue;
+        source
+      });
+    }
 
-          formatter._addExport(local.name, specifier.exported);
+    if (!t.isExportDefaultDeclaration(node) && !declar.isTypeAlias()) {
-        }
+      var onlyDefault = node.specifiers && node.specifiers.length === 1 && t.isSpecifierDefault(node.specifiers[0]);
+      if (!onlyDefault) {
+        formatter.hasNonDefaultExports = true;
       }
+    }
+  },
 
-      if (!t.isExportDefaultDeclaration(node)) {
+  Scope(node, parent, scope, formatter) {
-        var onlyDefault = node.specifiers && node.specifiers.length === 1 && t.isSpecifierDefault(node.specifiers[0]);
+    if (!formatter.isLoose()) {
-        if (!onlyDefault) {
+      this.skip();
-          formatter.hasNonDefaultExports = true;
-        }
-      }
     }
   }
 };
 
 export default class DefaultFormatter {
   constructor(file) {
-    this.internalRemap = object();
+    // object containg all module sources with the scope that they're contained in
-    this.defaultIds    = object();
+    this.sourceScopes = object();
-    this.scope         = file.scope;
+
-    this.file          = file;
+    // ids for use in module ids
-    this.ids           = object();
+    this.defaultIds = object();
+    this.ids        = object();
+
+    // contains reference aliases for live bindings
+    this.remaps = new Remaps(file, this);
+
+    this.scope = file.scope;
+    this.file  = file;
 
     this.hasNonDefaultExports = false;
 
@@ -128,8 +186,20 @@ export default class DefaultFormatter {
     this.localExports = object();
     this.localImports = object();
 
-    this.getLocalExports();
+    this.metadata = file.metadata.modules;
-    this.getLocalImports();
+    this.getMetadata();
+  }
+
+  addScope(path) {
+    var source = path.node.source && path.node.source.value;
+    if (!source) return;
+
+    var existingScope = this.sourceScopes[source];
+    if (existingScope && existingScope !== path.scope) {
+      throw path.errorWithNode(messages.get("modulesDuplicateDeclarations"));
+    }
+
+    this.sourceScopes[source] = path.scope;
   }
 
   isModuleType(node, type) {
@@ -145,17 +215,22 @@ export default class DefaultFormatter {
     return (t.isExportDefaultDeclaration(node) || t.isSpecifierDefault(node)) && !this.noInteropRequireExport && !this.hasNonDefaultExports;
   }
 
-  getLocalExports() {
+  getMetadata() {
-    this.file.path.traverse(exportsVisitor, this);
+    var has = false;
-  }
+    for (var node of (this.file.ast.program.body: Array)) {
-
+      if (t.isModuleDeclaration(node)) {
-  getLocalImports() {
+        has = true;
-    this.file.path.traverse(importsVisitor, this);
+        break;
+      }
+    }
+    if (has || this.isLoose()) {
+      this.file.path.traverse(metadataVisitor, this);
+    }
   }
 
   remapAssignments() {
     if (this.hasLocalExports || this.hasLocalImports) {
-      this.file.path.traverse(remapVisitor, this);
+      this.remaps.run();
     }
   }
 

src/babel/transformation/modules/_strict.js

@@ -10,4 +10,4 @@ export default function (Parent) {
   util.inherits(Constructor, Parent);
 
   return Constructor;
-};
+}

src/babel/transformation/modules/amd.js

@@ -6,8 +6,8 @@ import * as util from  "../../util";
 import * as t from "../../types";
 
 export default class AMDFormatter extends DefaultFormatter {
-  init() {
+  setup() {
-    CommonFormatter.prototype._init.call(this, this.hasNonDefaultExports);
+    CommonFormatter.prototype._setup.call(this, this.hasNonDefaultExports);
   }
 
   buildDependencyLiterals() {
@@ -72,7 +72,7 @@ export default class AMDFormatter extends DefaultFormatter {
     this.getExternalReference(node);
   }
 
-  importSpecifier(specifier, node, nodes) {
+  importSpecifier(specifier, node, nodes, scope) {
     var key = node.source.value;
     var ref = this.getExternalReference(node);
 
@@ -90,11 +90,11 @@ export default class AMDFormatter extends DefaultFormatter {
       // import * as bar from "foo";
     } else if (!includes(this.file.dynamicImported, node) && t.isSpecifierDefault(specifier) && !this.noInteropRequireImport) {
       // import foo from "foo";
-      var uid = this.scope.generateUidIdentifier(specifier.local.name);
+      var uid = scope.generateUidIdentifier(specifier.local.name);
       nodes.push(t.variableDeclaration("var", [
-        t.variableDeclarator(uid, t.callExpression(this.file.addHelper("interop-require"), [ref]))
+        t.variableDeclarator(uid, t.callExpression(this.file.addHelper("interop-require-default"), [ref]))
       ]));
-      ref = uid;
+      ref = t.memberExpression(uid, t.identifier("default"));
     } else {
       // import { foo } from "foo";
       var imported = specifier.imported;
@@ -102,7 +102,7 @@ export default class AMDFormatter extends DefaultFormatter {
       ref = t.memberExpression(ref, imported);
     }
 
-    this.internalRemap[specifier.local.name] = ref;
+    this.remaps.add(scope, specifier.local.name, ref);
   }
 
   exportSpecifier(specifier, node, nodes) {

src/babel/transformation/modules/common.js

@@ -1,14 +1,13 @@
 import DefaultFormatter from "./_default";
-import includes from "lodash/collection/includes";
 import * as util from  "../../util";
 import * as t from "../../types";
 
 export default class CommonJSFormatter extends DefaultFormatter {
-  init() {
+  setup() {
-    this._init(this.hasLocalExports);
+    this._setup(this.hasLocalExports);
   }
 
-  _init(conditional) {
+  _setup(conditional) {
     var file  = this.file;
     var scope = file.scope;
 
@@ -38,7 +37,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
     }
   }
 
-  importSpecifier(specifier, node, nodes) {
+  importSpecifier(specifier, node, nodes, scope) {
     var variableName = specifier.local;
 
     var ref = this.getExternalReference(node, nodes);
@@ -48,9 +47,9 @@ export default class CommonJSFormatter extends DefaultFormatter {
       if (this.isModuleType(node, "absolute")) {
         // absolute module reference
       } else if (this.isModuleType(node, "absoluteDefault")) {
-        this.internalRemap[variableName.name] = ref;
+        this.remaps.add(scope, variableName.name, ref);
       } else if (this.noInteropRequireImport) {
-        this.internalRemap[variableName.name] = t.memberExpression(ref, t.identifier("default"));
+        this.remaps.add(scope, variableName.name, t.memberExpression(ref, t.identifier("default")));
       } else {
         var uid = this.scope.generateUidIdentifierBasedOnNode(node, "import");
 
@@ -58,7 +57,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
           t.variableDeclarator(uid, t.callExpression(this.file.addHelper("interop-require-default"), [ref]))
         ]));
 
-        this.internalRemap[variableName.name] = t.memberExpression(uid, t.identifier("default"));
+        this.remaps.add(scope, variableName.name, t.memberExpression(uid, t.identifier("default")));
       }
     } else {
       if (t.isImportNamespaceSpecifier(specifier)) {
@@ -72,7 +71,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
         ]));
       } else {
         // import { foo } from "foo";
-        this.internalRemap[variableName.name] = t.memberExpression(ref, specifier.imported);
+        this.remaps.add(scope, variableName.name, t.memberExpression(ref, specifier.imported));
       }
     }
   }
@@ -84,7 +83,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
     }, true));
   }
 
-  exportSpecifier(specifier, node, nodes) {
+  exportSpecifier(specifier) {
     if (this.doDefaultExportInterop(specifier)) {
       this.hasDefaultOnlyExport = true;
     }
@@ -92,7 +91,7 @@ export default class CommonJSFormatter extends DefaultFormatter {
     DefaultFormatter.prototype.exportSpecifier.apply(this, arguments);
   }
 
-  exportDeclaration(node, nodes) {
+  exportDeclaration(node) {
     if (this.doDefaultExportInterop(node)) {
       this.hasDefaultOnlyExport = true;
     }
@@ -101,8 +100,6 @@ export default class CommonJSFormatter extends DefaultFormatter {
   }
 
   _getExternalReference(node, nodes) {
-    var source = node.source.value;
-
     var call = t.callExpression(t.identifier("require"), [node.source]);
     var uid;
 

src/babel/transformation/modules/ignore.js

@@ -1,6 +1,7 @@
+import DefaultFormatter from "./_default";
 import * as t from "../../types";
 
-export default class IgnoreFormatter {
+export default class IgnoreFormatter extends DefaultFormatter {
   exportDeclaration(node, nodes) {
     var declar = t.toStatement(node.declaration, true);
     if (declar) nodes.push(t.inherits(declar, node));
@@ -10,4 +11,5 @@ export default class IgnoreFormatter {
   importDeclaration() {}
   importSpecifier() {}
   exportSpecifier() {}
+  transform() {}
 }

src/babel/transformation/modules/lib/remaps.js

@@ -0,0 +1,121 @@
+import * as t from "../../../types";
+
+var remapVisitor = {
+  enter(node) {
+    if (node._skipModulesRemap) {
+      return this.skip();
+    }
+  },
+
+  ReferencedIdentifier(node, parent, scope, remaps) {
+    var { formatter } = remaps;
+
+    var remap = remaps.get(scope, node.name);
+    if (!remap || node === remap) return;
+
+    if (!scope.hasBinding(node.name) ||
+        scope.bindingIdentifierEquals(node.name, formatter.localImports[node.name])) {
+      if (!formatter.isLoose() && this.key === "callee" && this.parentPath.isCallExpression()) {
+        return t.sequenceExpression([t.literal(0), remap]);
+      } else {
+        return remap;
+      }
+    }
+  },
+
+  AssignmentExpression: {
+    exit(node, parent, scope, { formatter }) {
+      if (!node._ignoreModulesRemap) {
+        var exported = formatter.getExport(node.left, scope);
+        if (exported) {
+          return formatter.remapExportAssignment(node, exported);
+        }
+      }
+    }
+  },
+
+  UpdateExpression(node, parent, scope, { formatter }) {
+    var exported = formatter.getExport(node.argument, scope);
+    if (!exported) return;
+
+    this.skip();
+
+    // expand to long file assignment expression
+    var assign = t.assignmentExpression(node.operator[0] + "=", node.argument, t.literal(1));
+
+    // remap this assignment expression
+    var remapped = formatter.remapExportAssignment(assign, exported);
+
+    // we don't need to change the result
+    if (t.isExpressionStatement(parent) || node.prefix) {
+      return remapped;
+    }
+
+    var nodes = [];
+    nodes.push(remapped);
+
+    var operator;
+    if (node.operator === "--") {
+      operator = "+";
+    } else { // "++"
+      operator = "-";
+    }
+    nodes.push(t.binaryExpression(operator, node.argument, t.literal(1)));
+
+    return t.sequenceExpression(nodes);
+  }
+};
+export default class Remaps {
+  constructor(file, formatter) {
+    this.formatter = formatter;
+    this.file      = file;
+  }
+
+  run() {
+    this.file.path.traverse(remapVisitor, this);
+  }
+
+  _getKey(name) {
+    return `${name}:moduleRemap`;
+  }
+
+  get(scope, name) {
+    return scope.getData(this._getKey(name));
+  }
+
+  add(scope, name, val) {
+    if (this.all) {
+      this.all.push({
+        name,
+        scope,
+        node: val
+      });
+    }
+
+    return scope.setData(this._getKey(name), val);
+  }
+
+  remove(scope, name) {
+    return scope.removeData(this._getKey(name));
+  }
+
+  /**
+   * These methods are used by the system module formatter who needs access to all the remaps
+   * so it can process them into it's specific setter method. We don't do this by default since
+   * no other module formatters need access to this.
+   */
+
+  getAll() {
+    return this.all;
+  }
+
+  clearAll() {
+    if (this.all) {
+      for (var remap of (this.all: Array)) {
+        remap.scope.removeData(this._getKey(remap.name));
+      }
+    }
+
+    this.all = [];
+  }
+}

src/babel/transformation/modules/system.js

@@ -1,58 +1,56 @@
 import DefaultFormatter from "./_default";
 import AMDFormatter from "./amd";
-import object from  "../../helpers/object";
 import * as util from  "../../util";
 import last from "lodash/array/last";
-import each from "lodash/collection/each";
 import map from "lodash/collection/map";
 import * as t from "../../types";
 
 var hoistVariablesVisitor = {
-  enter(node, parent, scope, state) {
+  Function() {
-    if (t.isFunction(node)) {
+    // nothing inside is accessible
-      // nothing inside is accessible
+    this.skip();
-      return this.skip();
+  },
+
+  VariableDeclaration(node, parent, scope, state) {
+    if (node.kind !== "var" && !t.isProgram(parent)) { // let, const
+      // can't be accessed
+      return;
     }
 
-    if (t.isVariableDeclaration(node)) {
+    // ignore block hoisted nodes as these can be left in
-      if (node.kind !== "var" && !t.isProgram(parent)) { // let, const
+    if (state.formatter._canHoist(node)) return;
-        // can't be accessed
+
-        return;
+    var nodes = [];
+
+    for (var i = 0; i < node.declarations.length; i++) {
+      var declar = node.declarations[i];
+      state.hoistDeclarators.push(t.variableDeclarator(declar.id));
+      if (declar.init) {
+        // no initializer so we can just hoist it as-is
+        var assign = t.expressionStatement(t.assignmentExpression("=", declar.id, declar.init));
+        nodes.push(assign);
       }
-
-      // ignore block hoisted nodes as these can be left in
-      if (state.formatter._canHoist(node)) return;
-
-      var nodes = [];
-
-      for (var i = 0; i < node.declarations.length; i++) {
-        var declar = node.declarations[i];
-        state.hoistDeclarators.push(t.variableDeclarator(declar.id));
-        if (declar.init) {
-          // no initializer so we can just hoist it as-is
-          var assign = t.expressionStatement(t.assignmentExpression("=", declar.id, declar.init));
-          nodes.push(assign);
-        }
-      }
-
-      // for (var i in test)
-      // for (var i = 0;;)
-      if (t.isFor(parent) && parent.left === node) {
-        return node.declarations[0].id;
-      }
-
-      return nodes;
     }
+
+    // for (var i in test)
+    // for (var i = 0;;)
+    if (t.isFor(parent) && (parent.left === node || parent.init === node)) {
+      return node.declarations[0].id;
+    }
+
+    return nodes;
   }
 };
 
 var hoistFunctionsVisitor = {
-  enter(node, parent, scope, state) {
+  Function() {
-    if (t.isFunction(node)) this.skip();
+    this.skip();
+  },
 
+  enter(node, parent, scope, state) {
     if (t.isFunctionDeclaration(node) || state.formatter._canHoist(node)) {
       state.handlerBody.push(node);
-      this.remove();
+      this.dangerouslyRemove();
     }
   }
 };
@@ -71,7 +69,7 @@ var runnerSettersVisitor = {
         state.nodes.push(node);
       }
 
-      this.remove();
+      this.dangerouslyRemove();
     }
   }
 };
@@ -83,6 +81,8 @@ export default class SystemFormatter extends AMDFormatter {
     this.exportIdentifier = file.scope.generateUidIdentifier("export");
     this.noInteropRequireExport = true;
     this.noInteropRequireImport = true;
+
+    this.remaps.clearAll();
   }
 
   _addImportSource(node, exportNode) {
@@ -138,13 +138,13 @@ export default class SystemFormatter extends AMDFormatter {
   importSpecifier(specifier, node, nodes) {
     AMDFormatter.prototype.importSpecifier.apply(this, arguments);
 
-    for (var name in this.internalRemap) {
+    for (var remap of (this.remaps.getAll(): Array)) {
       nodes.push(t.variableDeclaration("var", [
-        t.variableDeclarator(t.identifier(name), this.internalRemap[name])
+        t.variableDeclarator(t.identifier(remap.name), remap.node)
       ]));
     }
 
-    this.internalRemap = object();
+    this.remaps.clearAll();
 
     this._addImportSource(last(nodes), node);
   }

src/babel/transformation/pipeline.js

@@ -1,10 +1,11 @@
-import Transformer from "./transformer";
+import PluginManager from "./file/plugin-manager";
 import normalizeAst from "../helpers/normalize-ast";
+import Plugin from "./plugin";
 import assign from "lodash/object/assign";
 import object from "../helpers/object";
 import File from "./file";
 
-export default class TransformerPipeline {
+export default class Pipeline {
   constructor() {
     this.transformers = object();
     this.namespaces   = object();
@@ -20,7 +21,7 @@ export default class TransformerPipeline {
     return this;
   }
 
-  addTransformer(key, transformer) {
+  addTransformer(key, plugin) {
     if (this.transformers[key]) throw new Error(); // todo: error
 
     var namespace = key.split(".")[0];
@@ -28,7 +29,19 @@ export default class TransformerPipeline {
     this.namespaces[namespace].push(key);
     this.namespaces[key] = namespace;
 
-    this.transformers[key] = new Transformer(key, transformer);
+    if (typeof plugin === "function") {
+      plugin = PluginManager.memoisePluginContainer(plugin);
+      plugin.key = key;
+      plugin.metadata.optional = true;
+
+      if (key === "react.displayName") {
+        plugin.metadata.optional = false;
+      }
+    } else {
+      plugin = new Plugin(key, plugin);
+    }
+
+    this.transformers[key] = plugin;
   }
 
   addAliases(names) {
@@ -46,21 +59,39 @@ export default class TransformerPipeline {
     return this;
   }
 
-  canTransform(transformer, fileOpts) {
+  canTransform(plugin, fileOpts) {
-    if (transformer.metadata.plugin) return true;
+    if (plugin.metadata.plugin) {
+      return true;
+    }
 
     for (var filter of (this.filters: Array)) {
-      var result = filter(transformer, fileOpts);
+      var result = filter(plugin, fileOpts);
       if (result != null) return result;
     }
 
     return true;
   }
 
+  analyze(code: string, opts?: Object = {}) {
+    opts.code = false;
+    return this.transform(code, opts);
+  }
+
+  pretransform(code: string, opts?: Object) {
+    var file = new File(opts, this);
+    return file.wrap(code, function () {
+      file.addCode(code);
+      file.parseCode(code);
+      return file;
+    });
+  }
+
   transform(code: string, opts?: Object) {
     var file = new File(opts, this);
     return file.wrap(code, function () {
-      file.addCode(code, true);
+      file.addCode(code);
+      file.parseCode(code);
+      return file.transform();
     });
   }
 
@@ -71,6 +102,7 @@ export default class TransformerPipeline {
     return file.wrap(code, function () {
       file.addCode(code);
       file.addAst(ast);
+      return file.transform();
     });
   }
 

src/babel/transformation/plugin-pass.js

@@ -0,0 +1,34 @@
+import type Transformer from "./transformer";
+import traverse from "../traversal";
+import type File from "./file";
+
+/**
+ * This class is responsible for traversing over the provided `File`s
+ * AST and running it's parent transformers handlers over it.
+ */
+
+export default class PluginPass {
+  constructor(file: File, plugin: Transformer) {
+    this.plugin = plugin;
+    this.file   = file;
+    this.key    = plugin.key;
+
+    if (this.canTransform() && plugin.metadata.experimental && !file.opts.experimental) {
+      file.log.warn(`THE TRANSFORMER ${this.key} HAS BEEN MARKED AS EXPERIMENTAL AND IS WIP. USE AT YOUR OWN RISK. ` +
+                    "THIS WILL HIGHLY LIKELY BREAK YOUR CODE SO USE WITH **EXTREME** CAUTION. ENABLE THE " +
+                    "`experimental` OPTION TO IGNORE THIS WARNING.");
+    }
+  }
+
+  canTransform(): boolean {
+    return this.file.transformerDependencies[this.key] ||
+           this.file.pipeline.canTransform(this.plugin, this.file.opts);
+  }
+
+  transform() {
+    var file = this.file;
+    file.log.debug(`Start transformer ${this.key}`);
+    traverse(file.ast, this.plugin.visitor, file.scope, file);
+    file.log.debug(`Finish transformer ${this.key}`);
+  }
+}

src/babel/transformation/plugin.js

@@ -0,0 +1,55 @@
+import PluginPass from "./plugin-pass";
+import * as messages from "../messages";
+import isFunction from "lodash/lang/isFunction";
+import traverse from "../traversal";
+import assign from "lodash/object/assign";
+import clone from "lodash/lang/clone";
+import File from "./file";
+
+export default class Plugin {
+  constructor(key: string, plugin: Object) {
+    plugin = assign({}, plugin);
+
+    var take = function (key) {
+      var val = plugin[key];
+      delete plugin[key];
+      return val;
+    };
+
+    this.manipulateOptions = take("manipulateOptions");
+    this.metadata          = take("metadata") || {};
+    this.dependencies      = this.metadata.dependencies || [];
+    this.post              = take("post");
+    this.pre               = take("pre");
+
+    //
+
+    if (this.metadata.stage != null) {
+      this.metadata.optional = true;
+    }
+
+    //
+
+    this.visitor = this.normalize(clone(take("visitor")) || {});
+    this.key     = key;
+  }
+
+  normalize(visitor: Object): Object {
+    if (isFunction(visitor)) {
+      visitor = { ast: visitor };
+    }
+
+    traverse.explode(visitor);
+
+    return visitor;
+  }
+
+  buildPass(file: File): PluginPass {
+    // validate Transformer instance
+    if (!(file instanceof File)) {
+      throw new TypeError(messages.get("pluginNotFile", this.key));
+    }
+
+    return new PluginPass(file, this);
+  }
+}

src/babel/transformation/templates/class-derived-default-constructor.js

@@ -0,0 +1,3 @@
+(function () {
+  super(...arguments);
+})

src/babel/transformation/templates/class-super-constructor-call-loose.js

@@ -1,3 +0,0 @@
-if (SUPER_NAME != null) {
-  SUPER_NAME.apply(this, arguments);
-}

src/babel/transformation/templates/class-super-constructor-call.js

@@ -1,3 +0,0 @@
-if (SUPER_NAME != null) {
-  SUPER_NAME.apply(this, arguments);
-}

src/babel/transformation/templates/class-super-native-constructor-call.js

@@ -1,5 +0,0 @@
-if (SUPER_NAME != null) {
-  var NATIVE_REF = new SUPER_NAME(...arguments);
-  NATIVE_REF.__proto__ = CLASS_NAME.prototype;
-  return NATIVE_REF;
-}

src/babel/transformation/templates/default-parameter-assign.js

@@ -0,0 +1 @@
+if (VARIABLE_NAME === undefined) VARIABLE_NAME = DEFAULT_VALUE;

src/babel/transformation/templates/helper-define-property.js

@@ -1,8 +1,18 @@
 (function (obj, key, value) {
-  return Object.defineProperty(obj, key, {
+  // Shortcircuit the slow defineProperty path when possible.
-    value: value,
+  // We are trying to avoid issues where setters defined on the
-    enumerable: true,
+  // prototype cause side effects under the fast path of simple
-    configurable: true,
+  // assignment. By checking for existence of the property with
-    writable: true
+  // the in operator, we can optimize most of this overhead away.
-  });
+  if (key in obj) {
+    Object.defineProperty(obj, key, {
+      value: value,
+      enumerable: true,
+      configurable: true,
+      writable: true
+    });
+  } else {
+    obj[key] = value;
+  }
+  return obj;
 });

src/babel/transformation/templates/helper-get.js

@@ -1,4 +1,6 @@
 (function get(object, property, receiver) {
+  if (object === null) object = Function.prototype;
+
   var desc = Object.getOwnPropertyDescriptor(object, property);
 
   if (desc === undefined) {

src/babel/transformation/templates/helper-sliced-to-array.js

@@ -1,7 +1,7 @@
-(function (arr, i) {
+(function () {
-  if (Array.isArray(arr)) {
+  // Broken out into a separate function to avoid deoptimizations due to the try/catch for the
-    return arr;
+  // array iterator case.
-  } else if (Symbol.iterator in Object(arr)) {
+  function sliceIterator(arr, i) {
     // this is an expanded form of `for...of` that properly supports abrupt completions of
     // iterators etc. variable names have been minimised to reduce the size of this massive
     // helper. sometimes spec compliancy is annoying :(
@@ -32,7 +32,15 @@
       }
     }
     return _arr;
-  } else {
-    throw new TypeError("Invalid attempt to destructure non-iterable instance");
   }
-});
+
+  return function (arr, i) {
+    if (Array.isArray(arr)) {
+      return arr;
+    } else if (Symbol.iterator in Object(arr)) {
+      return sliceIterator(arr, i);
+    } else {
+      throw new TypeError("Invalid attempt to destructure non-iterable instance");
+    }
+  };
+})();