v2.12.0

Add loose transform for tagged template literals

.gitignore

@@ -10,3 +10,4 @@ test/tmp
 /runtime.js
 coverage
 dist
+.package.json

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "vendor/regenerator"]
 	path = vendor/regenerator
 	url = https://github.com/facebook/regenerator
+[submodule "vendor/test262"]
+	path = vendor/test262
+	url = https://github.com/tc39/test262

.jshintrc

@@ -5,7 +5,6 @@
   "camelcase": true,
   "unused": true,
   "eqnull": true,
-  "proto": true,
   "newcap": true,
   "supernew": true,
   "noyield": true,
@@ -14,8 +13,6 @@
   "boss": true,
   "expr": true,
   "undef": true,
-  "loopfunc": true,
-  "white": true,
   "maxparams": 5,
   "maxdepth": 4,
 

.npmignore

@@ -9,3 +9,4 @@ Makefile
 dist
 tests.json
 CHANGELOG.md
+.package.json

CHANGELOG.md

@@ -7,25 +7,182 @@
 > - [Breaking Change]
 > - [Documentation]
 > - [Internal]
-> - [Misc]
+> - [Polish]
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 2.12.0
+
+ * **Bug Fix**
+  * Support non-string JSX literals.
+ * **New Feature**
+  * Loose mode for some transformers that enables non-spec behaviour.
+ * **Internal**
+  * Uglify `--mangle sort` has been added to the build script, cutting minified scripts in half.
+
+## 2.11.4
+
+ * **Internal**
+  * Make all dependency versions fixed.
+
+## 2.11.3
+
+ * **Bug Fix**
+  * Allow a string to be passed as the `optional` option.
+
+## 2.11.2
+
+ * **Bug Fix**
+  * Support esprima-style catch clause handlers.
+ * **Polish**
+  * Don't print a stacktrace for syntax errors in the CLI.
+
+## 2.11.1
+
+ * **Bug Fix**
+  * Remove stray `console.log` outputting debug code.
+  * Remove `Dict` from `coreAliasing`.
+
+## 2.11.0
+
+ * **Bug Fix**
+  * Fix unnecessary IIFE in default parameters on method calls.
+  * Add support for supers inside of closures.
+ * **New Feature**
+  * Add `--keep-module-id-extensions`/`keepModuleIdExtensions` option to keep extensions in module ids.
+ * **Polish**
+  * Special case single argument spread properties in `super` inside classes.
+  * Don't use a variable declaration for class declaration IFFE.
+  * Rename `inherits` helper parameters.
+  * `coreAliasing` transformer now aliases `Promise`, `Set`, `Map` and more. Thanks [@AluisioASG](https://github.com/AluisioASG).
+
+## 2.10.1
+
+ * **Internal**
+  * Upgrade `core-js` to `0.4.4`.
+ * **New Feature**
+  * Added `--include-regenerator` option to CLI and `includeRegenerator` option to API that includes the regenerator runtime if necessary.
+
+## 2.10.0
+
+ * **New Feature**
+  * Add `classesFastSuper` optional transformer that doesn't support parent getters and prototype changing.
+  * Add `forOfFast` transformer that speeds up `for...of` on arrays but produces more code.
+  * Add `--react-compat` to `bin/6to5`.
+ * **Spec Compliancy**
+  * Disallow setters without a single parameter.
+  * Add `configurable` and `writable` to defined properties.
+  * Use define instead of assignment for class methods.
+ * **Polish**
+  * Fix bin name in `6to5-node --help`.
+  * Fix shorthand `--whitelist` name in `bin/6to5`.
+ * **Internal**
+  * Hot code optimisation of traversal etc thanks to [gaearon](https://github.com/gaearon).
+
+## 2.9.4
+
+ * **Bug Fix**
+  * Support `UpdateExpression`s as `MemberExpression` objects.
+
+## 2.9.3
+
+ * **Bug Fix**
+  * Remove `exportsWildcard` helper in favor of `defaults`.
+
+## 2.9.2
+
+ * **Bug Fix**
+  * Pass `exports` to `exportWildcard` helper to allow for use inside the optional runtime.
+
+## 2.9.1
+
+ * **Bug Fix**
+  * Fix runtime generator breaking the helper inclusion loop.
+
+## 2.9.0
+
+ * **Internal**
+  * Upgrade `acorn-6to5`.
+    * Now supports destructuring shorthand properties.
+
+## 2.8.1
+
+ * **Bug Fix**
+  * Fix computed accessors on object literals.
+
+## 2.8.0
+
+ * **New Feature**
+  * Add `commonStrict`, `amdStrict` and `umdStrict` module formatters that remove `module.exports` interop assignment.
+  * Add `--indent` option to the 6to5 CLI.
+
+## 2.7.4
+
+ * **Polish**
+  * Inherit assignments from their declaration in destructuring.
+  * Properly align multi-declarator variable declarations.
+
+## 2.7.3
+
+ * **Polish**
+  * Indent and add newlines to `React.createElement` calls in `react` transformer.
+  * Remove `Object.assign` calls and replace it with an `extends` helper.
+
+## 2.7.1
+
+ * **New Feature**
+  * Expose `version` on browser and node API.
+ * **Internal**
+  * Upgrade `core-js` to 0.4.1
+
+## 2.7.0
+
+ * **Spec Compliancy**
+  * Disallow reassignments of imports.
+ * **New Feature**
+  * `reactCompat` option to enable pre-v0.12 react components.
+
+## 2.6.3
+
+ * **Bug Fix**
+  * Fix 2.6.0 regression caused by faulty export default from a source handling.
+
+## 2.6.2
+
+ * **Bug Fix**
+  * Fix rest parameter keys when on functions with params.
+
+## 2.6.1
+
+ * **Bug Fix**
+  * Fix rest parameter arguments key.
+
 ## 2.6.0
 
- * [Internal] Fix incorrect AST node `identifier("this")`.
- * [Spec Compliancy] Add `interopRequireWildcard` around wildcard imports and exports to handle non-object exports.
- * [Internal] Upgrade `acorn-6to5`.
- * [New Feature] Basic destructuring defaults
- * [New Feature] Add `.es` to list of supported extensions.
- * [New Feature] Add optional `typeofSymbol` transformer.
- * [Bug Fix] Better handling of number literal property keys.
- * [Bug Fix] [Internal] Better `toIdentifier` method that handles reserved words.
- * [Internal] Upgrade to `core-js` 4.0.0.
- * [Internal] Upgrade to `regenerator` 0.8.3.
- * [Bug Fix] Handle `NewExpression` paren insertion edegcases better.
- * [Spec Compliancy] Class inheritance now has a `function` or `null` type check.
- * [Misc] Move `"use strict";` to inside module bodies instead of at the top of the file.
+ * **Bug Fix**
+  * Better handling of number literal property keys.
+  * Handle `NewExpression` paren insertion edegcases better.
+ * **Internal**
+  * Fix incorrect AST node `identifier("this")`.
+  * Better `toIdentifier` method that handles reserved words.
+  * Upgrade `acorn-6to5`.
+    * Fix exponentiation operator precedence.
+    * Fix line terminators after async contextual keywords.
+    * Add semicolons as class elements inside of a class body.
+  * Upgrade to `core-js` 4.0.0.
+  * Upgrade to `regenerator` 0.8.3.
+    * Fix non-loop labeled statements.
+ * **New Feature**
+  * Basic destructuring defaults
+  * Add `.es` to list of supported extensions.
+  * Add optional `typeofSymbol` transformer.
+  * Use a `for` loop for rest parameters instead of `Array.prototype.slice`.
+ * **Polish**
+  * Move `"use strict";` to inside module bodies instead of at the top of the file.
+  * Better handling of dynamic imports.
+ * **Spec Compliancy**
+  * Class inheritance now has a `function` or `null` type check.
+  * Add `interopRequireWildcard` around wildcard imports and exports to handle non-object exports.
 
 ## 2.5.0
 

Makefile

@@ -1,12 +1,12 @@
 BROWSERIFY_CMD = node_modules/browserify/bin/cmd.js
 ISTANBUL_CMD = node_modules/istanbul/lib/cli.js cover
-UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs
+UGLIFY_CMD = node_modules/uglify-js/bin/uglifyjs --mangle sort
 JSHINT_CMD = node_modules/jshint/bin/jshint
 MOCHA_CMD = node_modules/mocha/bin/_mocha
 
 export NODE_ENV = test
 
-.PHONY: clean test test-cov test-clean lint test-travis test-spec test-browser publish bench build bootstrap
+.PHONY: clean test test-cov test-clean lint test-travis test-simple test-all test-browser publish build bootstrap publish-core
 
 build:
 	mkdir -p dist
@@ -27,12 +27,8 @@ build:
 clean:
 	rm -rf coverage templates.json test/tmp dist
 
-bench:
-	npm install es6-transpiler traceur esnext es6now jstransform
-	node node_modules/matcha/bin/_matcha
-
 lint:
-	$(JSHINT_CMD) --reporter node_modules/jshint-stylish/stylish.js lib bin benchmark/index.js
+	$(JSHINT_CMD) --reporter node_modules/jshint-stylish/stylish.js lib bin
 
 test-clean:
 	rm -rf test/tmp
@@ -41,14 +37,23 @@ test: lint
 	$(MOCHA_CMD)
 	make test-clean
 
+test-simple:
+	# excludes test262
+	export SIMPLE_6TO5_TESTS=1
+	make test
+
+test-all:
+	# includes traceur, esnext, regenerator
+	export ALL_6TO5_TESTS=1
+	make test
+
 test-cov:
+	export SIMPLE_6TO5_TESTS=1
 	rm -rf coverage
 	node $(ISTANBUL_CMD) $(MOCHA_CMD) --
 
-test-spec:
-	node $(ISTANBUL_CMD) $(MOCHA_CMD) -- --reporter spec
-
-test-travis: test-spec
+test-travis: bootstrap
+	node $(ISTANBUL_CMD) $(MOCHA_CMD) --
 	if test -n "$$CODECLIMATE_REPO_TOKEN"; then codeclimate < coverage/lcov.info; fi
 
 test-browser:
@@ -66,6 +71,9 @@ publish:
 
 	make test
 
+	read -p "Version: " version; \
+	npm version $$version --message "v%s"
+
 	make build
 	cp dist/6to5.min.js browser.js
 	cp dist/polyfill.min.js browser-polyfill.js
@@ -74,12 +82,21 @@ publish:
 	node bin/cache-templates
 	test -f templates.json
 
-	read -p "Version: "  version; \
-  npm version $$version --message "v%s"
 	npm publish
 
 	git push --follow-tags
 
+	# generate
+	bin/generate-core-package-json >package2.json
+	mv package.json .package.json
+	mv package2.json package.json
+
+	npm publish
+
+	# restore
+	rm -rf package.json
+	mv .package.json package.json
+
 	rm -rf templates.json browser.js runtime.js browser-polyfill.js
 
 bootstrap:

NOTES.md

@@ -1,3 +1,13 @@
 # Notes
 
- * Wildcard exports/imports wont normalise if `export default` is a non-object.
+ * Wildcard exports/imports wont normalise if `export default` is a non-object. See [#224](https://github.com/6to5/6to5/issues/224).
+
+## 3.0.0 breaking changes
+
+ * Remove `allowImportExportEverywhere` option from acorn.
+ * Remove this shorthand from playground.
+ * Remove `super()` inside non-constructors - add descriptive error message.
+ * Split up ES5 getter/setter transforming and ES6 property methods into separate transformers.
+ * Add autoindentation.
+ * Move `super` transformation from classes into a separate transformer that also supports object expressions.
+ * Prefix all fast transformers with `fast`, make them declare that they're a fast transformer similar to optional transformers and add a `--fast` flag to enable them all.

benchmark/fixtures/all.js

@@ -1,99 +0,0 @@
-var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
-var obj = {};
-var foo = "foo";
-var bar = "bar";
-
-// constants
-const MULTIPLIER = 5;
-
-// classes
-class Foo {
-  constructor() {
-    this.foo = "bar";
-  }
-}
-
-class Bar extends Foo {
-  constructor() {
-    super();
-  }
-
-  // default parameters
-  go(foo = "bar", bar = "foo") {
-
-  }
-
-  // not supported by jstransform
-  //get foo() {
-  //  return this._foo;
-  //}
-  //set foo(val) {
-  //  this._foo = val + " foo!";
-  //}
-}
-
-// arrow functions
-arr.map(x => x * x);
-
-// block binding
-for (let key in arr) {
-  let val = arr[key];
-  console.log(key, val);
-}
-
-// computed property names
-obj = {
-  ["foo" + bar]: "foobar"
-};
-
-// destructuring
-var [a, [b], c, d] = ["hello", [", ", "junk"], ["world"]];
-console.log(a + b + c);
-
-// array comprehension
-// [for (i of [1, 2, 3]) i * i]; // not supported by es6now
-
-// for-of
-for (var i of [1, 2, 3]) {
-  console.log(i * i);
-}
-
-// property method assignment
-obj = {
-  foo() {
-    return "foobar";
-  },
-
-  get bar() {
-    return this._bar;
-  },
-
-  set bar(val) {
-    this._bar = val;
-  }
-};
-
-// property name shorthand
-function f(x, y) {
-  return { x, y };
-}
-
-// rest parameters
-function printList(name, ...items) {
-  console.log("list %s has the following items", name);
-  items.forEach(function (item) {
-    console.log(item);
-  });
-}
-
-// spread
-function add(x, y) {
-  return x + y;
-}
-var numbers = [5, 10];
-add(...numbers);
-
-// template literals
-var x = 5;
-var y = 10;
-console.log(`${x} + ${y} = ${x + y}`);

benchmark/index.js

@@ -1,168 +0,0 @@
-Error.stackTraceLimit = Infinity;
-
-var jsTrans = require("jstransform");
-var traceur = require("traceur");
-//var es6tr   = require("es6-transpiler");
-var es6now  = require("es6now");
-//var esnext  = require("esnext");
-var to5     = require("../lib/6to5");
-
-//var uglify  = require("uglify-js");
-var matcha  = require("matcha");
-var path    = require("path");
-var fs      = require("fs");
-var _       = require("lodash");
-
-var readResolve = function (filename) {
-  try {
-    filename = require.resolve(filename);
-  } catch (err) {
-    return null;
-  }
-  return fs.readFileSync(filename, "utf8");
-};
-
-var getVersion = function (name) {
-  return require(name + "/package.json").version;
-};
-
-var jsTransVisitors = [];
-
-_.each([
-  "arrow-function-visitors", "class-visitors", "destructuring-visitors",
-  "object-concise-method-visitors", "object-short-notation-visitors",
-  "rest-param-visitors", "template-visitors"
-], function (name) {
-  var mod = require("jstransform/visitors/es6-" + name);
-  jsTransVisitors = jsTransVisitors.concat(mod.visitorList);
-});
-
-
-var compilers = {
-  "6to5": {
-    version: getVersion(".."),
-    compile: function (code, filename) {
-      return to5.transform(code, { filename: filename }).code;
-    }
-  },
-
-  traceur: {
-    runtime: readResolve("traceur/bin/traceur-runtime.js"),
-    compile: function (code) {
-      return traceur.compile(code, {
-        modules: "commonjs",
-        experimental: true
-      });
-    }
-  },
-
-  /*esnext: {
-    runtime: readResolve("esnext/node_modules/regenerator/runtime.js") || readResolve("regenerator/runtime.js"),
-    compile: function (code) {
-      return esnext.compile(code).code;
-    }
-  },*/
-
-  es6now: {
-    runtime: readResolve("es6now/runtime/ES6.js"),
-    compile: function (code) {
-      return es6now.translate(code);
-    }
-  },
-
-  /*"es6-transpiler": {
-    compile: function (code) {
-      var result = es6tr.run({ src: code });
-      if (result.errors.length) throw new Error(result.join("; "));
-      return result.src;
-    }
-  },*/
-
-  jstransform: {
-    compile: function (code) {
-      return jsTrans.transform(jsTransVisitors, code).code;
-    }
-  }
-};
-
-// versions
-
-//var uglifyTitle = "uglify v" + getVersion("uglify-js");
-
-_.each(compilers, function (compiler, name) {
-  compiler.title = name + " v" + (compiler.version || getVersion(name));
-});
-
-//
-
-var sizeBenchmark = function (code, loc, name, compiler) {
-  var log = function (output, title) {
-    title = [compiler.title].concat(title || []).join(" + ");
-
-    var text;
-    var color;
-    if (output.stack) {
-      text = "error";
-      color = "red";
-    } else {
-      var kilo  = (output.length / 1024).toFixed(2);
-      text = kilo + "KB";
-      color = "cyan";
-    }
-
-    text = matcha.utils.color(matcha.utils.padBefore(text, 22), color);
-
-    console.log(text, matcha.utils.color("» " + title, "gray"));
-
-    if (output.stack) {
-      console.error(output.stack);
-    }
-  };
-
-  var go = function (getOutput, title) {
-    var code;
-    try {
-      code = getOutput();
-    } catch (err) {
-      log(err, title);
-      return;
-    }
-
-    log(code, title);
-  };
-
-  var output;
-  go(function () {
-    return output = compiler.compile(code, loc);
-  });
-  if (!output) return;
-
-  //go(function () {
-  //  return uglify.minify(output, { fromString: true }).code;
-  //}, uglifyTitle);
-};
-
-//
-
-_.each(fs.readdirSync(__dirname + "/fixtures"), function (name) {
-  var alias = path.basename(name, path.extname(name));
-
-  suite(alias, function () {
-    set("delay", 0);
-
-    var loc  = __dirname + "/fixtures/" + name;
-    var code = fs.readFileSync(loc, "utf8");
-
-    before(function () {
-      _.each(compilers, function (compiler, name) {
-        sizeBenchmark(code, loc, name, compiler);
-      });
-    });
-
-    _.each(compilers, function (compiler) {
-      bench(compiler.title, function () {
-        compiler.compile(code, loc);
-      });
-    });
-  });
-});

bin/6to5/index.js

@@ -15,14 +15,19 @@ commander.option("-e, --experimental", "Enable experimental support for proposed
 commander.option("-p, --playground", "Enable playground support");
 
 commander.option("-m, --modules [modules]", "Module formatter type to use [common]", "common");
-commander.option("-w, --whitelist [whitelist]", "Whitelist of transformers to ONLY use", util.list);
+commander.option("-l, --whitelist [whitelist]", "Whitelist of transformers to ONLY use", util.list);
 commander.option("-b, --blacklist [blacklist]", "Blacklist of transformers to NOT use", util.list);
 commander.option("-i, --optional [list]", "List of optional transformers to enable", util.list);
+commander.option("--loose [list]", "List of transformers to enable their loose mode", util.list);
 commander.option("-o, --out-file [out]", "Compile all input files into a single file");
 commander.option("-d, --out-dir [out]", "Compile an input directory of modules into an output directory");
 commander.option("-c, --remove-comments", "Remove comments from the compiled code", false);
+commander.option("-I, --indent [width]", "Indent width [2]", 2);
 commander.option("-a, --amd-module-ids", "Insert module id in AMD modules", false); // todo: remove in 3.0.0
 commander.option("-m, --module-ids", "Insert module id in modules", false);
+commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
+commander.option("-E, --include-regenerator", "Include the regenerator runtime if necessary", false);
+commander.option("--keep-module-id-extensions", "Keep extensions when generating module ids", false);
 
 commander.on("--help", function(){
   var outKeys = function (title, obj) {
@@ -98,17 +103,26 @@ if (errors.length) {
 //
 
 exports.opts = {
-  sourceMapName: commander.outFile,
-  experimental:  commander.experimental,
-  playground:    commander.playground,
-  moduleIds:     commander.amdModuleIds || commander.moduleIds,
-  blacklist:     commander.blacklist,
-  whitelist:     commander.whitelist,
-  sourceMap:     commander.sourceMaps || commander.sourceMapsInline,
-  optional:      commander.optional,
-  comments:      !commander.removeComments,
-  runtime:       commander.runtime,
-  modules:       commander.modules
+  keepModuleIdExtensions: commander.keepModuleIdExtensions,
+  includeRegenerator:     commander.includeRegenerator,
+  sourceMapName:          commander.outFile,
+  experimental:           commander.experimental,
+  reactCompat:            commander.reactCompat,
+  playground:             commander.playground,
+  moduleIds:              commander.amdModuleIds || commander.moduleIds,
+  blacklist:              commander.blacklist,
+  whitelist:              commander.whitelist,
+  sourceMap:              commander.sourceMaps || commander.sourceMapsInline,
+  optional:               commander.optional,
+  comments:               !commander.removeComments,
+  runtime:                commander.runtime,
+  modules:                commander.modules,
+  loose:                  commander.loose,
+  format: {
+    indent: {
+      style:     util.repeat(parseInt(commander.indent))
+    }
+  }
 };
 
 var fn;

bin/6to5/util.js

@@ -20,7 +20,17 @@ exports.transform = function (filename, code, opts) {
   opts = _.extend(opts || {}, index.opts);
   opts.filename = filename;
 
-  var result = to5.transform(code, opts);
+  var result;
+  try {
+    result = to5.transform(code, opts);
+  } catch (e) {
+    if (e instanceof SyntaxError) {
+      console.error("SyntaxError:", e.message);
+      process.exit(1);
+    } else {
+      throw e;
+    }
+  }
   result.filename = filename;
   result.actual = code;
   return result;

bin/_6to5-node

@@ -10,29 +10,31 @@ var util       = require("../lib/6to5/util");
 var vm         = require("vm");
 var _          = require("lodash");
 
-commander.option("-e, --eval [script]", "Evaluate script");
-commander.option("-p, --print", "Evaluate script and print result");
-commander.option("-i, --ignore [regex]", "Ignore all files that match this regex when using the require hook");
-commander.option("-x, --extensions [extensions]", "List of extensions to hook into [.es6,.js]");
-commander.option("-r, --experimental", "Enable experimental support for proposed ES7 features");
-commander.option("-g, --playground", "Enable playground support");
-commander.option("-c, --cache", "Cache compiled files and require paths");
+var program = new commander.Command("6to5-node");
+
+program.option("-e, --eval [script]", "Evaluate script");
+program.option("-p, --print", "Evaluate script and print result");
+program.option("-i, --ignore [regex]", "Ignore all files that match this regex when using the require hook");
+program.option("-x, --extensions [extensions]", "List of extensions to hook into [.es6,.js]");
+program.option("-r, --experimental", "Enable experimental support for proposed ES7 features");
+program.option("-g, --playground", "Enable playground support");
+program.option("-c, --cache", "Cache compiled files and require paths");
 
 var pkg = require("../package.json");
-commander.version(pkg.version);
-commander.usage("[options] [ -e script | script.js ] [arguments]");
-commander.parse(process.argv);
+program.version(pkg.version);
+program.usage("[options] [ -e script | script.js ] [arguments]");
+program.parse(process.argv);
 
-if (commander.cache) roadrunner.load();
+if (program.cache) roadrunner.load();
 
 //
 
 to5.register({
-  experimental: commander.experimental,
-  extensions:   commander.extensions,
-  playground:   commander.playground,
-  ignore:       commander.ignore,
-  cache:        commander.cache && roadrunner.get("6to5")
+  experimental: program.experimental,
+  extensions:   program.extensions,
+  playground:   program.playground,
+  ignore:       program.ignore,
+  cache:        program.cache && roadrunner.get("6to5")
 });
 
 //
@@ -41,17 +43,17 @@ var _eval = function (code, filename) {
   code = to5.transform(code, {
     filename: filename,
     blacklist: ["useStrict"],
-    experimental: commander.experimental,
-    playground: commander.playground
+    experimental: program.experimental,
+    playground: program.playground
   }).code;
   return vm.runInThisContext(code, filename);
 };
 
-if (commander.eval) {
-  var result = _eval(commander.eval, "eval");
-  if (commander.print) console.log(result);
+if (program.eval) {
+  var result = _eval(program.eval, "eval");
+  if (program.print) console.log(result);
 } else {
-  if (commander.args.length) {
+  if (program.args.length) {
     // slice all arguments up to the first filename since they're 6to5 args that we handle
     var args = process.argv.slice(2);
 
@@ -77,7 +79,7 @@ if (commander.eval) {
   }
 }
 
-if (commander.cache) roadrunner.save();
+if (program.cache) roadrunner.save();
 
 function replStart() {
   repl.start({

bin/generate-core-package-json

@@ -0,0 +1,11 @@
+#!/usr/bin/env node
+
+var pkg = require("../package.json");
+pkg.name += "-core";
+delete pkg.dependencies.chokidar;
+delete pkg.optionalDependencies;
+delete pkg.devDependencies;
+delete pkg.preferGlobal;
+delete pkg.scripts;
+delete pkg.bin;
+console.log(JSON.stringify(pkg, null, "  "));

doc/browser.md

@@ -1,65 +0,0 @@
-# Browser
-
-A browser version of 6to5 is available from `browser.js` inside the 6to5
-directory in an npm release.
-
-## Scripts
-
-While it's not recommended for serious use, when the browser version is included
-all scripts with the type `text/ecmascript-6` and `text/6to5` are automatically
-compiled and ran.
-
-For example:
-
-```html
-<script src="node_modules/6to5/browser.js"></script>
-<script type="text/6to5">
-class Test {
-  test() {
-    return "test";
-  }
-}
-
-var test = new Test;
-test.test();
-</script>
-```
-
-## Build
-
-You can build a browser version of the compiler by running the following in the
-6to5 directory:
-
-```sh
-$ make build
-```
-
-This will output the files `dist/6to5.js` and `dist/6to5.min.js`.
-
-## Test
-
-To test 6to5 in your browser run:
-
-```sh
-$ make test-browser
-```
-
-And open `test/browser.html` in your browser if it doesn't open automatically.
-
-## API
-
-### to5.transform(code, [opts])
-
-See [options](usage.md#options) for additional documentation.
-
-```javascript
-to5.transform("class Test {}").code;
-```
-
-### to5.run(code, [opts])
-
-See [options](usage.md#options) for additional documentation.
-
-```javascript
-to5.run("class Test {}");
-```

doc/caveats.md

@@ -1,62 +0,0 @@
-# Caveats
-
-In order for certain features to work they require certain polyfills. You can
-satisfy **all** 6to5 feature requirements by using the included
-[polyfill](polyfill.md).
-
-You may alternatively selectively include what you need:
-
-| Feature                     | Requirements                                                                                                           |
-| --------------------------- | ---------------------------------------------------------------------------------------------------------------------- |
-| Abstract References         | [experimental](experimental.md), `Symbol`                                                                              |
-| Array destructuring         | `Array.from`                                                                                                           |
-| Async functions, Generators | [experimental](experimental.md), [regenerator runtime](https://github.com/facebook/regenerator/blob/master/runtime.js) |
-| Comprehensions              | [experimental](experimental.md), `Array.from`                                                                          |
-| For Of                      | `Symbol`, `prototype[Symbol.iterator]`                                                                                 |
-| Modules                     | `Object.assign`*                                                                                                       |
-| Object spread/rest          | [experimental](experimental.md), `Object.assign`                                                                       |
-| Spread                      | `Array.from`                                                                                                           |
-
-*Only required for exporting a non-function `default` with additional `export`s.
-
-## ES5
-
-Since 6to5 assumes that your code will be ran in an ES5 environment it uses ES5
-functions. So if you're using an environment that has limited or no support for
-ES5 such as lower versions of IE then using the
-[es5-shim](https://github.com/es-shims/es5-shim) along with the
-[6to5 polyfill](polyfill.md) will add support for these methods.
-
-## Internet Explorer
-
-### Classes (10 and below)
-
-If you're inheriting from a class then static properties are inherited from it
-via [\_\_proto\_\_](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto),
-this is widely supported but you may run into problems with much older browsers.
-
-**NOTE:** `__proto__` is not supported in IE <= 10 so static properties
-**will not** be inherited. A possible workaround is to use `super();`:
-
-```javascript
-class Foo {
-  static foo() {
-
-  }
-}
-
-class Bar extends Foo {
-  static foo() {
-    super();
-  }
-}
-```
-
-## Getters/setters (8 and below)
-
-In IE8 `Object.defineProperty` can only be used on DOM objects. This is
-unfortunate as it's required to set getters and setters. Due to this if
-you plan on supporting IE8 or below then the user of getters and setters
-isn't recommended.
-
-**Reference**: [MDN](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty#Internet_Explorer_8_specific_notes).

doc/differences.md

@@ -1,137 +0,0 @@
-# Differences
-
-There are three main points that separate 6to5 from all other transpilers.
-
-### Readable code
-
-The fundamental concept behind 6to5 is that the generated code must be close as
-possible to the original, retaining all the same formatting and readability.
-
-Many other transpilers are just concerned with making the code work while 6to5
-is concerned with making sure it works **and** is readable at the same time.
-
-For example, given the following array comprehension:
-
-```javascript
-var seattlers = [for (c of customers) if (c.city == "Seattle") { name: c.name, age: c.age }];
-```
-
-is generated to the following with 6to5:
-
-```javascript
-var seattlers = Array.from(customers).filter(function (c) {
-  return c.city == "Seattle";
-}).map(function (c) {
-  return {
-    name: c.name,
-    age: c.age
-  };
-});
-```
-
-The following is what Traceur generates:
-
-```javascript
-var seattlers = (function() {
-  var c;
-  var $__20 = 0,
-      $__21 = [];
-  for (var $__22 = customers[$traceurRuntime.toProperty(Symbol.iterator)](),
-      $__23; !($__23 = $__22.next()).done; ) {
-    c = $__23.value;
-    if (c.city == "Seattle")
-      $traceurRuntime.setProperty($__21, $__20++, {
-        name: c.name,
-        age: c.age
-      });
-  }
-  return $__21;
-}());
-```
-
-As you can tell, it's not very pretty. Instead of mapping directly to a
-runtime, like other transpilers, 6to5 maps directly to the equivalent ES5.
-
-Sometimes there are little inline functions that 6to5 needs. These are
-placed at the top of your file much like coffee-script does. If these
-bother you then you can use the [optional runtime](optional-runtime.md).
-We promise that these inline functions will never be significant and will
-always be used as little as possible.
-
-### Static analysis
-
-6to5 uses a lot of static analysis to simplify code as much as possible.
-Not many other transpilers do this, and those that do don't do it nearly
-as much as 6to5. This process is pretty intensive but it leads to higher
-quality code.
-
-### Spec compliancy
-
-6to5 prides itself on
-[spec compliancy](https://kangax.github.io/compat-table/es6/). We have
-excellent support for edgecases, something that many other transpilers
-suffer from, including Traceur. When you use 6to5 you can be confident
-that when you turn it off and use your code in a full ES6 environment
-**it'll just work**.
-
-## Comparison to other transpilers
-
-### Features
-
-|                              | 6to5 | Traceur | es6-transpiler | es6now | jstransform |
-| ---------------------------- | ---- | ------- | -------------- | ------ | ----------- |
-| Source maps                  | ✓    | ✓       | ✓              |        | ✓           |
-| No compiler global pollution | ✓    |         | ✓              |        | ✓           |
-| Optional runtime             | ✓    |         | ✓              |        | ✓           |
-| Browser compiler             | ✓    | ✓       |                |        |             |
-
-### Language Support
-
-|                              | 6to5 | Traceur | es6-transpiler | es6now | jstransform |
-| ---------------------------- | ---- | ------- | -------------- | ------ | ----------- |
-| Abstract references          | ✓    |         |                |        |             |
-| Array comprehension          | ✓    | ✓       | ✓              |        |             |
-| Arrow functions              | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Async functions              | ✓    | ✓       |                |        |             |
-| Async generator functions    | ✓    | ✓       |                |        |             |
-| Classes                      | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Computed property names      | ✓    | ✓       | ✓              | ✓      |             |
-| Constants                    | ✓    | ✓       | ✓              |        |             |
-| Default parameters           | ✓    | ✓       | ✓              | ✓      |             |
-| Destructuring                | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Exponentiation operator      | ✓    | ✓       |                |        |             |
-| Flow types                   | ✓    |         |                |        | ✓           |
-| For-of                       | ✓    | ✓       | ✓              | ✓      |             |
-| Generators                   | ✓    | ✓       |                |        |             |
-| Generator comprehension      | ✓    | ✓       |                |        |             |
-| JSX                          | ✓    |         |                |        |             |
-| Let scoping                  | ✓    | ✓       | ✓              |        |             |
-| Modules                      | ✓    | ✓       |                | ✓      |             |
-| Object rest/spread           | ✓    |         |                |        | ✓           |
-| Property method assignment   | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Property name shorthand      | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Rest parameters              | ✓    | ✓       | ✓              | ✓      | ✓           |
-| React                        | ✓    |         |                |        |             |
-| Spread                       | ✓    | ✓       | ✓              | ✓      |             |
-| Template literals            | ✓    | ✓       | ✓              | ✓      | ✓           |
-| Unicode regex                | ✓    | ✓       | ✓              |        |             |
-
-### [Traceur](https://github.com/google/traceur-compiler)
-
-Traceur requires quite a bulky runtime (~75KB) and produces quite verbose code.
-While this can be trimmed down by selectively building the runtime, it's an
-unnecessary step when a large runtime can be eliminated entirely.
-
-### [es6now](https://github.com/zenparsing/es6now)
-
-es6now doesn't output sourcemaps. This is cited as a positive as line-to-line
-mapping is the goal. This however obviously doesn't retain column mapping
-resulting in the output code not being very pleasant.
-
-### [es6-transpiler](https://github.com/termi/es6-transpiler)
-
-The es6-transpiler compiler requires shims to operate which pollutes the global
-scope resulting in possible collisions.
-
-es6-transpiler maps line-by-line, just like es6now, this results in the same
-issues such as lack of column information and unpleasant code output.

doc/experimental.md

@@ -1,8 +0,0 @@
-## Experimental
-
-6to5 also has experimental support for ES7 proposals. You can enable this with
-the `experimental: true` option when using the [Node API](#node) or
-`--experimental` when using the [CLI](#cli).
-
-**WARNING:** These proposals are subject to change so use with
-**extreme caution**.

doc/features.md

@@ -1,283 +0,0 @@
-# Features
-
-## Abstract references ([experimental](experimental.md)) ([spec](https://github.com/zenparsing/es-abstract-refs))
-
-```javascript
-foo::bar;
-foo::bar = baz;
-delete foo::bar;
-```
-
-## Array comprehensions ([experimental](experimental.md))
-
-```javascript
-var results = [for (c of customers) if (c.city == "Seattle") { name: c.name, age: c.age }]
-```
-
-## Arrow functions
-
-```javascript
-// Expression bodies
-var odds = evens.map(v => v + 1);
-var nums = evens.map((v, i) => v + i);
-
-// Statement bodies
-nums.forEach(v => {
-  if (v % 5 === 0)
-    fives.push(v);
-});
-
-// Lexical this
-var bob = {
-  _name: "Bob",
-  _friends: [],
-  printFriends() {
-    this._friends.forEach(f => {
-      console.log(this._name + " knows " + f);
-    });
-  }
-};
-```
-
-## Async functions ([experimental](experimental.md)) ([spec](https://github.com/lukehoban/ecmascript-asyncawait))
-
-```javascript
-async function chainAnimationsAsync(elem, animations) {
-  for (var anim of animations) {
-    await anim(elem);
-  }
-}
-```
-
-## Async generator functions ([experimental](experimental.md)) ([spec](https://github.com/jhusain/asyncgenerator))
-
-```javascript
-
-```
-
-## Classes
-
-```javascript
-class SkinnedMesh extends THREE.Mesh {
-  constructor(geometry, materials) {
-    super(geometry, materials);
-
-    this.idMatrix = SkinnedMesh.defaultMatrix();
-    this.bones = [];
-    this.boneMatrices = [];
-    //...
-  }
-
-  update(camera) {
-    //...
-    super.update();
-  }
-
-  static defaultMatrix() {
-    return new THREE.Matrix4();
-  }
-}
-```
-
-## Computed property names
-
-```javascript
-var foo = "foo";
-var bar = "bar";
-var obj = {
-  ["foo" + bar]: "heh",
-  ["bar" + foo]: "noo",
-  foo: "foo",
-  bar: "bar"
-};
-```
-
-## Constants
-
-```javascript
-const MULTIPLIER = 5;
-console.log(2 * MULTIPLIER);
-
-MULTIPLIER = 6; // error
-var MULTIPLIER; // error
-```
-
-## Default parameters
-
-```javascript
-function f(x, y = 12) {
-  // y is 12 if not passed (or passed as undefined)
-  return x + y;
-}
-f(3) == 15
-```
-
-## Destructuring
-
-```javascript
-// list matching
-var [a, , b] = [1,2,3];
-
-// object matching
-var { op: a, lhs: { op: b }, rhs: c } = getASTNode();
-
-// object matching shorthand
-// binds `op`, `lhs` and `rhs` in scope
-var { op, lhs, rhs } = getASTNode();
-
-// Can be used in parameter position
-function g({ name: x }) {
-  console.log(x);
-}
-g({ name: 5 });
-
-// Fail-soft destructuring
-var [a] = [];
-a === undefined;
-```
-
-## Exponentiation operator ([experimental](experimental.md)) ([spec](https://github.com/rwaldron/exponentiation-operator))
-
-```javascript
-var a = 2;
-a **= 2;
-
-var squared = 2 ** 2;
-```
-
-## For-of
-
-```javascript
-for (var i of [1, 2, 3]) {
-  console.log(i * i);
-}
-```
-
-## Generators
-
-```javascript
-function* fibonacci() {
-  var pre = 0, cur = 1;
-  for (;;) {
-    var temp = pre;
-    pre = cur;
-    cur += temp;
-    yield cur;
-  }
-}
-
-for (var n of fibonacci()) {
-  // truncate the sequence at 1000
-  if (n > 1000) break;
-  console.log(n);
-}
-```
-
-## Generator comprehensions ([experimental](experimental.md))
-
-```javascript
-var nums = [1, 2, 3, 4, 5, 6];
-var multiples = (for (i of nums) if (i % 2) i * i);
-assert.equal(multiples.next().value, 1);
-assert.equal(multiples.next().value, 9);
-assert.equal(multiples.next().value, 25);
-```
-
-## Let scoping
-
-```javascript
-for (let i in arr) {
-  let v = arr[i];
-}
-```
-
-## Modules
-
-```javascript
-import "foo";
-import foo from "foo";
-import * as foo from "foo";
-import {bar} from "foo";
-import {foo as bar} from "foo";
-
-export { test };
-export var test = 5;
-export function test() {}
-
-export default test;
-```
-
-## Numeric literals
-
-```javascript
-0b111110111 === 503; // true
-0o767 === 503; // true
-```
-
-## Object spread/rest ([experimental](experimental.md)) ([spec](https://github.com/sebmarkbage/ecmascript-rest-spread))
-
-```javascript
-var n = { x, y, ...z };
-var { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
-```
-
-## Property method assignment
-
-```javascript
-var obj = {
-  foo() {
-    return "foobar";
-  },
-
-  get bar() {
-    return this._bar;
-  },
-
-  set bar(val) {
-    this._bar = val;
-  }
-};
-```
-
-## Property name shorthand
-
-```javascript
-function f(x, y) {
-  return { x, y };
-}
-```
-
-## Rest parameters
-
-```javascript
-function f(x, ...y) {
-  // y is an Array
-  return x * y.length;
-}
-f(3, "hello", true) == 6
-```
-
-## Spread
-
-```javascript
-function f(x, y, z) {
-  return x + y + z;
-}
-// Pass each elem of array as argument
-f(...[1,2,3]) == 6
-```
-
-## Template literals
-
-```javascript
-var x = 5;
-var y = 10;
-console.log(`${x} + ${y} = ${x + y}`); // "5 + 10 = 15"
-```
-## Unicode regex
-
-```javascript
-var string = 'foo💩bar';
-var match = string.match(/foo(.)bar/u);
-console.log(match[1]);
-```

doc/index.md

@@ -1,62 +1 @@
-**6to5** turns ES6+ code into vanilla ES5, so you can use next generation features **today.**
-
- - **Readable** - formatting is retained if possible so your generated code is as similar as possible.
- - **Extensible** - with a large range of [plugins](plugins.md) and **browser support**.
- - **Lossless** - **source map support** so you can debug your compiled code with ease.
- - **Compact** - maps directly to the equivalent ES5 with **no runtime**[\*](caveats.md).
-
-## Installation
-
-It's as easy as:
-
-    $ npm install -g 6to5
-
-## Usage
-
-Once you've installed 6to5, there are multiple paths you can take depending on
-how you want to use it.
-
-6to5 will simply compile your ES6+ script to ES5 if you pass it as an argument
-to the command-line tool `6to5`:
-
-```sh
-$ 6to5 script.js
-```
-
-If you have a file written using ES6+ and you just want to run it, `6to5-node`
-has you covered:
-
-```sh
-$ 6to5-node script.js
-```
-
-And it doesn't end here! To see all the ways you can use 6to5, check out the
-[Usage](http://6to5.github.io/usage.html) page.
-
-## [Features](features.md)
-
- - [Abstract references](features.md#abstract-references) ([experimental](experimental.md))
- - [Array comprehension](features.md#array-comprehension) ([experimental](experimental.md))
- - [Async functions](features.md#async-functions) ([experimental](experimental.md))
- - [Async generator functions](features.md#async-generator-functions) ([experimental](experimental.md))
- - [Arrow functions](features.md#arrow-functions)
- - [Classes](features.md#classes)
- - [Computed property names](features.md#computed-property-names)
- - [Constants](features.md#constants)
- - [Default parameters](features.md#default-parameters)
- - [Destructuring](features.md#destructuring)
- - [Exponentiation operator](features.md#exponentiation-operator) ([experimental](experimental.md))
- - [For-of](features.md#for-of)
- - [Generators](features.md#generators)
- - [Generator comprehension](features.md#generator-comprehension) ([experimental](experimental.md))
- - [Let scoping](features.md#let-scoping)
- - [Modules](features.md#modules)
- - [Numeric literals](features.md#numeric-literals)
- - [Object rest/spread](features.md#object-rest-spread) ([experimental](experimental.md))
- - [Property method assignment](features.md#property-method-assignment)
- - [Property name shorthand](features.md#property-name-shorthand)
- - [React/JSX](react.md)
- - [Rest parameters](features.md#rest-parameters)
- - [Spread](features.md#spread)
- - [Template literals](features.md#template-literals)
- - [Unicode regex](features.md#unicode-regex)
+See [6to5.github.io/docs](https://github.com/6to5/6to5.github.io/tree/master/docs).

doc/modules.md

@@ -1,257 +0,0 @@
-# Modules
-
-## Usage
-
-### CLI
-
-```sh
-$ 6to5 --modules common script.js
-```
-
-### Node
-
-```javascript
-var to5 = require("6to5");
-to5.transform('import "foo";', { modules: "common" });
-```
-
-## Formats
-
- * [AMD](#amd)
- * [Common (Default)](#common-default)
- * [Ignore](#ignore)
- * [System](#system)
- * [UMD](#umd)
-
-### Common
-
-```sh
-$ 6to5 --modules common
-```
-
-**In**
-
-```javascript
-export default test;
-
-export {test};
-export var test = 5;
-
-import "foo";
-
-import foo from "foo";
-import * as foo from "foo";
-
-import {bar} from "foo";
-import {foo as bar} from "foo";
-```
-
-**Out**
-
-```javascript
-"use strict";
-
-var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
-};
-
-exports = module.exports = test;
-
-exports.test = test;
-var test = exports.test = 5;
-
-require("foo");
-
-var foo = _interopRequire(require("foo"));
-
-var foo = require("foo");
-
-var bar = require("foo").bar;
-var bar = require("foo").foo;
-```
-
-### AMD
-
-```sh
-$ 6to5 --modules amd
-```
-
-**In**
-
-```javascript
-import foo from "foo";
-
-export function bar() {
-  return foo("foobar");
-}
-```
-
-**Out**
-
-```javascript
-define(["exports", "foo"], function (exports, _foo) {
-  "use strict";
-
-  var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
-  };
-
-  exports.bar = bar;
-  var foo = _interopRequire(_foo);
-
-  function bar() {
-    return foo("foobar");
-  }
-});
-```
-
-You can optionally specify to include the module id (using the `--amd-module-id` argument):
-
-```javascript
-define("filename", ["exports", "foo"], function (exports, _foo) {})
-```
-
-### UMD
-
-```sh
-$ 6to5 --modules umd
-```
-
-**In**
-
-```javascript
-import foo from "foo";
-
-export function bar() {
-  return foo("foobar");
-}
-```
-
-**Out**
-
-```javascript
-(function (factory) {
-  if (typeof define === "function" && define.amd) {
-    define(["exports", "foo"], factory);
-  } else if (typeof exports !== "undefined") {
-    factory(exports, require("foo"));
-  }
-})(function (exports, _foo) {
-  "use strict";
-
-  var _interopRequire = function (obj) {
-    return obj && (obj["default"] || obj);
-  };
-
-  exports.bar = bar;
-  var foo = _interopRequire(_foo);
-
-  function bar() {
-    return foo("foobar");
-  }
-});
-```
-
-### Ignore
-
-```sh
-$ 6to5 --modules ignore
-```
-
-**In**
-
-```javascript
-import foo from "foo";
-
-export function bar() {
-  return foo("foobar");
-}
-```
-
-**Out**
-
-```javascript
-function bar() {
-  return foo("foobar");
-}
-```
-
-### System
-
-```sh
-$ 6to5 --modules system
-```
-
-**In**
-
-```javascript
-import foo from "foo";
-
-export function bar() {
-  return foo("foobar");
-}
-```
-
-**Out**
-
-```javascript
-System.register("bar", ["foo"], function (_export) {
-  "use strict";
-
-  var __moduleName = "bar";
-
-  var foo;
-  function bar() {
-    return foo("foobar");
-  }
-  return {
-    setters: [function (m) {
-      foo = m.default;
-    }],
-    execute: function () {
-      _export("bar", bar);
-    }
-  };
-});
-```
-
-## Custom
-
-You can alternatively specify module names instead of one of the built-in types.
-
-```sh
-$ 6to5 --modules custom-module-formatter
-```
-
-**node_modules/custom-module-formatter/index.js**
-
-```javascript
-module.exports = ModuleFormatter;
-
-function ModuleFormatter() {
-
-}
-
-ModuleFormatter.prototype.transform = function (ast) {
-  // this is ran after all transformers have had their turn at modifying the ast
-  // feel free to modify this however
-};
-
-ModuleFormatter.prototype.importDeclaration = function (node, nodes) {
-  // node is an ImportDeclaration
-};
-
-ModuleFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
-  // specifier is an ImportSpecifier
-  // node is an ImportDeclaration
-};
-
-ModuleFormatter.prototype.exportDeclaration = function (node, nodes) {
-  // node is an ExportDeclaration
-};
-
-ModuleFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
-  // specifier is an ExportSpecifier
-  // node is an ExportDeclaration
-};
-```

doc/optional-runtime.md

@@ -1,57 +0,0 @@
-# Optional runtime
-
-6to5 has a few helper functions that'll be placed at the top of the generated
-code if needed so it's not inlined multiple times throughout that file. This may
-become an issue if you have multiple files, especially when you're sending them
-to the browser. gzip alleviates most of this concern but it's still not ideal.
-
-You can tell 6to5 to not place any declarations at the top of your files and
-instead just point them to a reference contained within the runtime.
-
-Simply use the following option if you're using the [Node API](usage.md#node):
-
-```javascript
-{
-  runtime: true
-}
-```
-
-or the following flag if you're using the [CLI](usage.md#cli):
-
-```ssh
-$ 6to5 --runtime
-```
-
-Then just include the runtime before your generated code.
-
-## Getting the runtime
-
-You can get the runtime via either:
-
-```sh
-$ 6to5-runtime
-```
-
-or
-
-```javascript
-require("6to5").runtime();
-```
-
-or from an npm release in `runtime.js` from the 6to5 directory.
-
-## Customising namespace
-
-You can also customise the runtime namespace by passing an optional namespace
-argument:
-
-```javascript
-require("6to5").runtime("myCustomNamespace");
-```
-
-```sh
-$ 6to5-runtime myCustomNamespace
-```
-
-See [Options - runtime](usage.md#options) for documentation on changing the
-reference in generated code.

doc/playground.md

@@ -1,140 +0,0 @@
-# Playground
-
-Playground is a proving ground for **possible** ES7 proposals.
-
-**NOTE: These features are in no way endorsed by Ecma International and are not a part of ES6. They might become a part of ECMAScript in the future.**
-
-## Usage
-
-    $ 6to5 --playground
-
-```javascript
-to5.transform("code", { playground: true });
-```
-
-**NOTE:** Enabling `playground` also enables [experimental support](experimental.md).
-
-## Features
-
- * [Memoization operator](#memoization-operator)
- * [Method binding](#method-binding)
- * [Method binding function shorthand](#method-binding-function-shorthand)
- * [Object getter memoization](#object-getter-memoization)
- * [This shorthand](#this-shorthand)
-
-### Memoization assignment operator
-
-The memoization assignment operator allows you to lazily set an object property.
-It checks whether there's a property defined on the object and if there isn't then
-the right hand value is set.
-
-This means that `obj.x` in the following `var x = { x: undefined }; obj.x ?= 2;`
-will still be `undefined` because it's already been defined on the object.
-
-```javascript
-var obj = {};
-obj.x ?= 2;
-obj.x; // 2
-
-obj = { x: 1 };
-obj.x ?= 2;
-obj.x; // 1
-
-obj = { x: undefined }
-obj.x ?= 2;
-obj.x; // undefined
-```
-
-```javascript
-var obj = {};
-obj.x ?= 2;
-```
-
-equivalent to
-
-```javascript
-var obj = {};
-if (!Object.prototype.hasOwnProperty.call(obj, "x")) obj.x = 2;
-```
-
-### Method binding
-
-```javascript
-var fn = obj#method;
-var fn = obj#method("foob");
-```
-
-equivalent to
-
-```javascript
-var fn = obj.method.bind(obj);
-var fn = obj.method.bind(obj, "foob");
-```
-
-### Method binding function shorthand
-
-```javascript
-["foo", "bar"].map(#toUpperCase); // ["FOO", "BAR"]
-[1.1234, 23.53245, 3].map(#toFixed(2)); // ["1.12", "23.53", "3.00"]
-```
-
-equivalent to
-
-```javascript
-["foo", "bar"].map(function (val) { return val.toUpperCase(); });
-[1.1234, 23.53245, 3].map(function (val) { return val.toFixed(2); });
-```
-
-### Object getter memoization
-
-```javascript
-var foo = {
-  memo bar() {
-    return complex();
-  }
-};
-
-class Foo {
-  memo bar() {
-    return complex();
-  }
-}
-```
-
-equivalent to
-
-```javascript
-var foo = {
-  get bar() {
-    return Object.defineProperty(this, "bar", {
-      value: complex(),
-      enumerable: true,
-      configurable: true,
-      writable: true
-    }).bar;
-  }
-};
-
-class Foo {
-  get bar() {
-    return Object.defineProperty(this, "bar", {
-      value: complex(),
-      enumerable: true,
-      configurable: true,
-      writable: true
-    }).bar;
-  }
-}
-```
-
-### This shorthand
-
-```javascript
-@foo
-```
-
-equivalent to
-
-```javascirpt
-this.foo
-```

doc/plugins.md

@@ -1,33 +0,0 @@
-# Plugins
-
-## Build systems
-
- - [Broccoli](https://github.com/6to5/broccoli-6to5-transpiler)
- - [Browserify](https://github.com/6to5/6to5ify)
- - [Brunch](https://github.com/6to5/6to5-brunch)
- - [Duo](https://github.com/6to5/duo6to5)
- - [Gobble](https://github.com/6to5/gobble-6to5)
- - [Gulp](https://github.com/6to5/gulp-6to5)
- - [Grunt](https://github.com/6to5/grunt-6to5)
- - [Sprockets](https://github.com/josh/sprockets-es6) or via [Browserify](https://github.com/6to5/6to5-rails)
- - [webpack](https://github.com/6to5/6to5-loader)
-
-## Integrations
-
- - [Isparta](https://github.com/douglasduteil/isparta) - Code coverage with `karma` and `instanbul` using 6to5
- - [JSXHint](https://github.com/STRML/JSXHint) - A wrapper around JSHint to allow linting of JSX files
-
-## Bridges
-
- - [Ruby](https://github.com/6to5/6to5-ruby)
-
-## Testing
-
- - [Jest](https://github.com/6to5/6to5-jest)
- - [Karma](https://github.com/6to5/karma-6to5-preprocessor)
- - [Mocha](https://github.com/6to5/6to5-mocha)
-
-## Misc
-
- - [Connect](https://github.com/6to5/6to5-connect)
- - [Jade](https://github.com/6to5/jade-6to5)

doc/polyfill.md

@@ -1,34 +0,0 @@
-# Polyfill
-
-6to5 includes a polyfill that includes a custom
-[regenerator runtime](https://github.com/facebook/regenerator/blob/master/runtime.js) and
-[core.js](https://github.com/zloirock/core-js).
-
-This will emulate a full ES6 environment. This polyfill is automatically loaded
-when using [6to5-node](usage.md#node) and [6to5/register](usage.md#register-hook).
-
-## Usage
-
-### Node/Browserify
-
-You need to include the polyfill require at the top the **entry point** to your
-application.
-
-```javascript
-require("6to5/polyfill");
-```
-
-Fortunately, this is automatically loaded when using:
-
-```javascript
-require("6to5/register");
-```
-
-### Browser
-
-Available from the `browser-polyfill.js` file within the 6to5 directory of an
-npm release. This needs to be included **before** all your compiled 6to5 code.
-You can either prepend it to your compiled code or include it in a `<script>`
-before it.
-
-**NOTE:** Do not `require` this via browserify etc, use `6to5/polyfill`.

doc/react.md

@@ -1,17 +0,0 @@
-# React/JSX
-
-6to5 has built-in support for React v0.12. Tags are automatically transformed to
-their equivalent `React.createElement(...)` and `displayName` is automatically
-inferred and added to all `React.createClass` calls.
-
-## Blacklist
-
-To disable this behaviour add `react` to your blacklist:
-
-```javascript
-to5.transform("code", { blacklist: ["react"] });
-```
-
-```sh
-$ 6to5 --blacklist react
-```

doc/usage.md

@@ -1,259 +0,0 @@
-# Usage
-
-## CLI
-
-Compile the file `script.js` and output it to stdout.
-
-```sh
-$ 6to5 script.js
-```
-
-Compile the file `script.js` and output it to `script-compiled.js`.
-
-```sh
-$ 6to5 script.js --out-file script-compiled.js
-```
-
-Compile the file `script.js` and output it to `script-compiled.js` and save a
-source map to `script-compiled.js.map`.
-
-```sh
-$ 6to5 script.js --source-maps --out-file script-compiled.js
-```
-
-Compile the file `script.js` and output it to `script-compiled.js` with a source
-map embedded in a comment at the bottom.
-
-```sh
-$ 6to5 script.js --source-maps-inline --out-file script-compiled.js
-```
-
-Compile the entire `src` directory and output it to the `lib` directory.
-
-```sh
-$ 6to5 src --out-dir lib
-```
-
-Compile the entire `src` directory and output it to the one concatenated file.
-
-```sh
-$ 6to5 src --out-file script-compiled.js
-```
-
-Pipe a file in via stdin and output it to `script-compiled.js`
-
-```sh
-$ 6to5 --out-file script-compiled.js < script.js
-```
-
-### Node
-
-Launch a repl.
-
-```sh
-$ 6to5-node
-```
-
-Evaluate code.
-
-```sh
-$ 6to5-node -e "class Test { }"
-```
-
-Compile and run `test.js`.
-
-```sh
-$ 6to5-node test
-```
-
-## Node
-
-```javascript
-var to5 = require("6to5");
-```
-
-### to5.transform(code, [opts]);
-
-```javascript
-var result = to5.transform("code();", options);
-result.code;
-result.map;
-result.ast;
-```
-
-### to5.transformFileSync(filename, [opts])
-
-```javascript
-to5.transformFileSync("filename.js", options).code;
-```
-
-### to5.transformFile(filename, [opts], callback)
-
-```javascript
-to5.transformFile("filename.js", options, function (err, result) {
-  result.code;
-});
-```
-
-### to5.transform.fromAst(ast, [code], [opts])
-
-```javascript
-var result = to5.transform.fromAst(ast, "var a = 2;", opts);
-result.code;
-result.map;
-result.ast;
-```
-
-#### Options
-
-```javascript
-{
-  // Filename for use in errors etc.
-  // Default: "unknown"
-  filename: "filename",
-
-  // Filename relative to `sourceRoot`
-  // Default: `filename` option.
-  filenameRelative: "",
-
-  // List of transformers to EXCLUDE.
-  // Run `6to5 --help` to see a full list of transformers.
-  blacklist: [],
-
-  // List of transformers to ONLY use.
-  // Run `6to5 --help` to see a full list of transformers.
-  whitelist: [],
-
-  // Module formatter to use
-  // Run `6to5 --help` to see a full list of module formatters.
-  // Default: "common"
-  modules: "common",
-
-  // If truthy, adds a `map` property to returned output.
-  // If set to "inline", a comment with a sourceMappingURL directive is added to
-  // the bottom of the returned code.
-  // Default: false
-  sourceMap: true,
-
-  // Set `file` on returned source map.
-  // Default: `filenameRelative` option.
-  sourceMapName: "filename",
-
-  // Set `sources[0]` on returned source map.
-  // Default: `filenameRelative` option.
-  sourceFileName: "filename",
-
-  // The root from which all sources are relative
-  // Default: `moduleRoot` option.
-  sourceRoot: "assets/scripts",
-
-  // Optional prefix for the AMD module formatter that will be prepend to the
-  // filename on module definitions
-  // Default: `sourceRoot` option.
-  moduleRoot: "my-app",
-
-  // If truthy, insert an explicit id for each defined AMD/System module.
-  // By default, AMD/System modules are anonymous.
-  // Default: false
-  moduleIds: true,
-
-  // Optionally replace all 6to5 helper declarations with a referenece to this
-  // variable. If set to `true` then the default namespace is used "to5Runtime".
-  // Default: false
-  runtime: true,
-
-  // Enable support for experimental ES7 features
-  // Default: false
-  experimental: true,
-
-  // Set this to `false` if you don't want the transformed AST in the returned
-  // result
-  // Default: true
-  ast: true,
-
-  // Set this to `false` if you don't want the transformed code in the returned
-  // result
-  // Default: true
-  code: true,
-
-  format: {
-    // Output comments in generated output
-    // Default: true
-    comments: true,
-
-    // Do not include superfluous whitespace characters and line terminators
-    // Default: false
-    compact: false,
-
-    indent: {
-      // Preserve parentheses in new expressions that have no arguments
-      // Default: true
-      parentheses: true,
-
-      // Adjust the indentation of multiline comments to keep asterisks vertically aligned
-      // Default: true
-      adjustMultilineComment: true,
-
-      // Indent string
-      // Default: "  "
-      style: "  ",
-
-      // Base indent level
-      // Default: 0
-      base: 0
-    }
-  }
-}
-```
-
-### Require hook
-
-All subsequent files required by node with the extensions `.es6`, `.es` and `.js` will
-be transformed by 6to5. The polyfill specified in [Polyfill](polyfill.md) is
-also required; but this is automatically loaded when using:
-
-Source maps are automatically configured so if any errors a thrown then line
-number info is mapped and you'll get the correct source location.
-
-```javascript
-require("6to5/register");
-```
-
-**NOTE:** By default all requires to `node_modules` will be ignored. You can
-override this by passing an ignore regex via:
-
-```javascript
-require("6to5/register")({
-  // This will override `node_modules` ignoring - you can alternatively pass
-  // a regex
-  ignore: false
-});
-```
-
-**NOTE:** Using 6to5-node or `require("6to5/register")`, 6to5 will check what features are available in the current environment and blacklists them if they're supported.
-
-#### Options
-
-```javascript
-require("6to5/register")({
-  // Optional ignore regex - if any filenames **do** match this regex then they
-  // aren't compiled
-  ignore: /regex/,
-
-  // Optional only regex - if any filenames **don't** match this regex then they
-  // aren't compiled
-  only: /my_es6_folder/,
-
-  // See options above for usage
-  whitelist: [],
-  blacklist: [],
-
-  // This will remove the currently hooked extensions of .es6 and .js so you'll
-  // have to add them back if you want them to be used again.
-  extensions: [".js", ".es6"],
-
-  // Enables `roadrunner` cache that will save to a `.roadrunner.json` file in your cwd
-  // Do not check this into git as it's user-specific
-  cache: true
-});
-```

lib/6to5/browser.js

@@ -1,5 +1,7 @@
 var transform = module.exports = require("./transformation/transform");
 
+transform.version = require("../../package").version;
+
 transform.transform = transform;
 
 transform.run = function (code, opts) {

lib/6to5/file.js

@@ -24,6 +24,7 @@ File.helpers = [
   "prototype-properties",
   "apply-constructor",
   "tagged-template-literal",
+  "tagged-template-literal-loose",
   "interop-require",
   "to-array",
   "sliced-to-array",
@@ -35,32 +36,38 @@ File.helpers = [
   "async-to-generator",
   "interop-require-wildcard",
   "typeof",
-  "exports-wildcard"
+  "extends",
+  "get"
 ];
 
 File.excludeHelpersFromRuntime = [
   "async-to-generator",
-  "typeof"
+  "typeof",
+  "tagged-template-literal-loose"
 ];
 
 File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
 
   _.defaults(opts, {
-    experimental: false,
-    playground:   false,
-    whitespace:   true,
-    moduleIds:    opts.amdModuleIds || false,
-    blacklist:    [],
-    whitelist:    [],
-    sourceMap:    false,
-    optional:     [],
-    comments:     true,
-    filename:     "unknown",
-    modules:      "common",
-    runtime:      false,
-    code:         true,
-    ast:          true
+    keepModuleIdExtensions: false,
+    includeRegenerator:     false,
+    experimental:           false,
+    reactCompat:            false,
+    playground:             false,
+    whitespace:             true,
+    moduleIds:              opts.amdModuleIds || false,
+    blacklist:              [],
+    whitelist:              [],
+    sourceMap:              false,
+    optional:               [],
+    comments:               true,
+    filename:               "unknown",
+    modules:                "common",
+    runtime:                false,
+    loose:                  [],
+    code:                   true,
+    ast:                    true
   });
 
   // normalise windows path separators to unix
@@ -68,6 +75,19 @@ File.normaliseOptions = function (opts) {
 
   opts.blacklist = util.arrayify(opts.blacklist);
   opts.whitelist = util.arrayify(opts.whitelist);
+  opts.optional  = util.arrayify(opts.optional);
+  opts.loose     = util.arrayify(opts.loose);
+
+  // todo: remove in 3.0.0
+  _.each({
+    fastForOf: "forOf",
+    classesFastSuper: "classes"
+  }, function (newTransformer, oldTransformer) {
+    if (_.contains(opts.optional, oldTransformer)) {
+      _.pull(opts.optional, oldTransformer);
+      opts.loose.push(newTransformer);
+    }
+  });
 
   _.defaults(opts, {
     moduleRoot: opts.sourceRoot
@@ -97,10 +117,15 @@ File.normaliseOptions = function (opts) {
   transform._ensureTransformerNames("blacklist", opts.blacklist);
   transform._ensureTransformerNames("whitelist", opts.whitelist);
   transform._ensureTransformerNames("optional", opts.optional);
+  transform._ensureTransformerNames("loose", opts.loose);
 
   return opts;
 };
 
+File.prototype.isLoose = function (key) {
+  return _.contains(this.opts.loose, key);
+};
+
 File.prototype.getTransformers = function () {
   var file = this;
   var transformers = [];

lib/6to5/generation/buffer.js

@@ -61,7 +61,7 @@ Buffer.prototype.space = function () {
 Buffer.prototype.removeLast = function (cha) {
   if (!this.isLast(cha)) return;
 
-  this.buf = this.buf.slice(0, -1);
+  this.buf = this.buf.substr(0, this.buf.length - 1);
   this.position.unshift(cha);
 };
 
@@ -77,10 +77,9 @@ Buffer.prototype.newline = function (i, removeLast) {
     if (this.endsWith("{\n")) i--;
     if (this.endsWith(util.repeat(i, "\n"))) return;
 
-    var self = this;
-    _.times(i, function () {
-      self.newline(null, removeLast);
-    });
+    for (var j = 0; j < i; j++) {
+      this.newline(null, removeLast);
+    }
     return;
   }
 
@@ -115,13 +114,18 @@ Buffer.prototype._push = function (str) {
 };
 
 Buffer.prototype.endsWith = function (str) {
-  return this.buf.slice(-str.length) === str;
+  var d = this.buf.length - str.length;
+  return d >= 0 && this.buf.lastIndexOf(str) === d;
 };
 
 Buffer.prototype.isLast = function (cha, trimRight) {
   var buf = this.buf;
   if (trimRight) buf = util.trimRight(buf);
+  var last = buf[buf.length - 1];
 
-  var chars = [].concat(cha);
-  return _.contains(chars, _.last(buf));
+  if (Array.isArray(cha)) {
+    return _.contains(cha, last);
+  } else {
+    return cha === last;
+  }
 };

lib/6to5/generation/generator.js

@@ -125,7 +125,7 @@ CodeGenerator.prototype.print = function (node, parent, opts) {
 
     var lines = 0;
 
-    if (node.start != null) {
+    if (node.start != null && !node._ignoreUserWhitespace) {
       // user node
       if (leading) {
         lines = self.whitespace.getNewlinesBefore(node);

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

@@ -57,8 +57,28 @@ exports.ThisExpression = function () {
 
 exports.CallExpression = function (node, print) {
   print(node.callee);
+
   this.push("(");
-  print.join(node.arguments, { separator: ", " });
+
+  var separator = ",";
+
+  if (node._prettyCall) {
+    separator += "\n";
+    this.newline();
+    this.indent();
+  } else {
+    separator += " ";
+  }
+
+  print.join(node.arguments, {
+    separator: separator
+  });
+
+  if (node._prettyCall) {
+    this.newline();
+    this.dedent();
+  }
+
   this.push(")");
 };
 

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

@@ -1,4 +1,5 @@
-var t = require("../../types");
+var util = require("../../util");
+var t    = require("../../types");
 
 exports.WithStatement = function (node, print) {
   this.keyword("with");
@@ -106,7 +107,16 @@ exports.TryStatement = function (node, print) {
   this.keyword("try");
   print(node.block);
   this.space();
-  print(node.handler);
+
+  // 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]);
+  } else {
+    print(node.handler);
+  }
+
   if (node.finalizer) {
     this.space();
     this.push("finally ");
@@ -157,7 +167,24 @@ exports.DebuggerStatement = function () {
 exports.VariableDeclaration = function (node, print, parent) {
   this.push(node.kind + " ");
 
-  print.join(node.declarations, { separator: ", " });
+  var inits = 0;
+  var noInits = 0;
+  for (var i in node.declarations) {
+    if (node.declarations[i].init) {
+      inits++;
+    } else {
+      noInits++;
+    }
+  }
+
+  var sep = ",";
+  if (inits > noInits) { // more inits than noinits
+    sep += "\n" + util.repeat(node.kind.length + 1);
+  } else {
+    sep += " ";
+  }
+
+  print.join(node.declarations, { separator: sep });
 
   if (!t.isFor(parent)) {
     this.semicolon();

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

@@ -6,14 +6,19 @@ var t          = require("../../types");
 var _          = require("lodash");
 
 var find = function (obj, node, parent) {
+  if (!obj) return;
   var result;
 
-  _.each(obj, function (fn, type) {
+  var types = Object.keys(obj);
+  for (var i = 0; i < types.length; i++) {
+    var type = types[i];
+
     if (t["is" + type](node)) {
+      var fn = obj[type];
       result = fn(node, parent);
-      if (result != null) return false;
+      if (result != null) break;
     }
-  });
+  }
 
   return result;
 };
@@ -99,7 +104,13 @@ _.each(Node.prototype, function (fn, key) {
   Node[key] = function (node, parent) {
     var n = new Node(node, parent);
 
-    var args = _.toArray(arguments).slice(2);
+    // Avoid leaking arguments to prevent deoptimization
+    var skipCount = 2;
+    var args = new Array(arguments.length - skipCount);
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i + 2];
+    }
+
     return n[key].apply(n, args);
   };
 });

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

@@ -21,6 +21,13 @@ _.each([
   });
 });
 
+exports.UpdateExpression = function (node, parent) {
+  if (t.isMemberExpression(parent) && parent.object === node) {
+    // (foo++).test()
+    return true;
+  }
+};
+
 exports.ObjectExpression = function (node, parent) {
   if (t.isExpressionStatement(parent)) {
     // ({ foo: "bar" });

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

@@ -62,11 +62,15 @@ _.each({
   CallExpression: { after: 1 },
   Literal: { after: 1 }
 }, function (amounts, type) {
-  if (_.isNumber(amounts)) amounts = { after: amounts, before: amounts };
+  if (_.isNumber(amounts)) {
+    amounts = { after: amounts, before: amounts };
+  }
 
-  _.each(amounts, function (amount, key) {
-    exports[key].nodes[type] = function () {
-      return amount;
-    };
+  _.each([type].concat(t.FLIPPED_ALIAS_KEYS[type] || []), function (type) {
+    _.each(amounts, function (amount, key) {
+      exports[key].nodes[type] = function () {
+        return amount;
+      };
+    });
   });
 });

lib/6to5/generation/position.js

@@ -1,33 +1,27 @@
 module.exports = Position;
 
-var _ = require("lodash");
-
 function Position() {
   this.line = 1;
   this.column = 0;
 }
 
 Position.prototype.push = function (str) {
-  var self = this;
-
-  _.each(str, function (cha) {
-    if (cha === "\n") {
-      self.line++;
-      self.column = 0;
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] === "\n") {
+      this.line++;
+      this.column = 0;
     } else {
-      self.column++;
+      this.column++;
     }
-  });
+  }
 };
 
 Position.prototype.unshift = function (str) {
-  var self = this;
-
-  _.each(str, function (cha) {
-    if (cha === "\n") {
-      self.line--;
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] === "\n") {
+      this.line--;
     } else {
-      self.column--;
+      this.column--;
     }
-  });
+  }
 };

lib/6to5/generation/whitespace.js

@@ -11,15 +11,18 @@ Whitespace.prototype.getNewlinesBefore = function (node) {
   var startToken;
   var endToken;
   var tokens = this.tokens;
+  var token;
+
+  for (var i = 0; i < tokens.length; i++) {
+    token = tokens[i];
 
-  _.each(tokens, function (token, i) {
     // this is the token this node starts with
     if (node.start === token.start) {
       startToken = tokens[i - 1];
       endToken = token;
-      return false;
+      break;
     }
-  });
+  }
 
   return this.getNewlinesBetween(startToken, endToken);
 };
@@ -28,20 +31,29 @@ Whitespace.prototype.getNewlinesAfter = function (node) {
   var startToken;
   var endToken;
   var tokens = this.tokens;
+  var token;
+
+  for (var i = 0; i < tokens.length; i++) {
+    token = tokens[i];
 
-  _.each(tokens, function (token, i) {
     // this is the token this node ends with
     if (node.end === token.end) {
       startToken = token;
       endToken = tokens[i + 1];
-      return false;
+      break;
     }
-  });
+  }
 
   if (endToken.type.type === "eof") {
     return 1;
   } else {
-    return this.getNewlinesBetween(startToken, endToken);
+    var lines = this.getNewlinesBetween(startToken, endToken);
+    if (node.type === "Line" && !lines) {
+      // line comment
+      return 1;
+    } else {
+      return lines;
+    }
   }
 };
 

lib/6to5/index.js

@@ -3,6 +3,8 @@ var util      = require("./util");
 var fs        = require("fs");
 var _         = require("lodash");
 
+exports.version = require("../../package").version;
+
 exports.types = require("./types");
 
 exports.runtime = require("./runtime-generator");

lib/6to5/register-browser.js

@@ -1,4 +1,5 @@
-// Required to safely use 6to5/register within a browserify codebase.
+// required to safely use 6to5/register within a browserify codebase
+
 module.exports = function () {};
 
 require("./polyfill");

lib/6to5/runtime-generator.js

@@ -20,7 +20,7 @@ module.exports = function (namespace) {
 
   _.each(File.helpers, function (name) {
     if (_.contains(File.excludeHelpersFromRuntime, name)) {
-      return false;
+      return;
     }
 
     var key = t.identifier(t.toIdentifier(name));

lib/6to5/transformation/modules/_default.js

@@ -9,7 +9,11 @@ function DefaultFormatter(file) {
   this.file = file;
 
   this.localExports = this.getLocalExports();
+  this.localImports = this.getLocalImports();
+
   this.remapAssignments();
+
+  //this.checkCollisions();
 }
 
 DefaultFormatter.prototype.getLocalExports = function () {
@@ -27,6 +31,53 @@ DefaultFormatter.prototype.getLocalExports = function () {
   return localExports;
 };
 
+DefaultFormatter.prototype.getLocalImports = function () {
+  var localImports = {};
+
+  traverse(this.file.ast, {
+    enter: function (node) {
+      if (t.isImportDeclaration(node)) {
+        _.extend(localImports, t.getIds(node, true));
+      }
+    }
+  });
+
+  return localImports;
+};
+
+DefaultFormatter.prototype.checkCollisions = function () {
+  // todo: all check export collissions
+
+  var localImports = this.localImports;
+  var file = this.file;
+
+  var isLocalReference = function (node) {
+    return t.isIdentifier(node) && _.has(localImports, node.name) && localImports[node.name] !== node;
+  };
+
+  var check = function (node) {
+    if (isLocalReference(node)) {
+      throw file.errorWithNode(node, "Illegal assignment of module import");
+    }
+  };
+
+  traverse(file.ast, {
+    enter: function (node) {
+      if (t.isAssignmentExpression(node)) {
+
+        var left = node.left;
+        if (t.isMemberExpression(left)) {
+          while (left.object) left = left.object;
+        }
+
+        check(left);
+      } else if (t.isDeclaration(node)) {
+        _.each(t.getIds(node, true), check);
+      }
+    }
+  });
+};
+
 DefaultFormatter.prototype.remapExportAssignment = function (node) {
   return t.assignmentExpression(
     "=",
@@ -105,11 +156,16 @@ DefaultFormatter.prototype.getModuleName = function () {
     filenameRelative = filenameRelative.replace(sourceRootRegEx, "");
   }
 
-  // remove extension
-  filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  if (!opts.keepModuleIdExtensions) {
+    // remove extension
+    filenameRelative = filenameRelative.replace(/\.(.*?)$/, "");
+  }
 
   moduleName += filenameRelative;
 
+  // normalise path separators
+  moduleName = moduleName.replace(/\\/g, "/");
+
   return moduleName;
 };
 
@@ -142,10 +198,11 @@ DefaultFormatter.prototype._exportSpecifier = function (getRef, specifier, node,
       nodes.push(this._exportsWildcard(getRef(), node));
     } else {
       var ref;
-      if (t.isSpecifierDefault(specifier.id) || this.noInteropRequire) {
-        ref = t.memberExpression(getRef(), specifier.id);
-      } else {
+      if (t.isSpecifierDefault(specifier) && !this.noInteropRequire) {
+        // importing a default so we need to normalise it
         ref = t.callExpression(this.file.addHelper("interop-require"), [getRef()]);
+      } else {
+        ref = t.memberExpression(getRef(), specifier.id);
       }
 
       // export { foo } from "test";
@@ -162,7 +219,8 @@ DefaultFormatter.prototype._exportSpecifier = function (getRef, specifier, node,
 };
 
 DefaultFormatter.prototype._exportsWildcard = function (objectIdentifier) {
-  return t.expressionStatement(t.callExpression(this.file.addHelper("exports-wildcard"), [
+  return t.expressionStatement(t.callExpression(this.file.addHelper("defaults"), [
+    t.identifier("exports"),
     t.callExpression(this.file.addHelper("interop-require-wildcard"), [objectIdentifier])
   ]));
 };

lib/6to5/transformation/modules/_strict.js

@@ -0,0 +1,12 @@
+var util = require("../../util");
+
+module.exports = function (Parent) {
+  var Constructor = function () {
+    this.noInteropExport = true;
+    Parent.apply(this, arguments);
+  };
+
+  util.inherits(Constructor, Parent);
+
+  return Constructor;
+};

lib/6to5/transformation/modules/amd-strict.js

@@ -0,0 +1 @@
+module.exports = require("./_strict")(require("./amd"));

lib/6to5/transformation/modules/amd.js

@@ -1,13 +1,14 @@
 module.exports = AMDFormatter;
 
 var DefaultFormatter = require("./_default");
+var CommonFormatter  = require("./common");
 var util             = require("../../util");
 var t                = require("../../types");
 var _                = require("lodash");
 
 function AMDFormatter() {
-  DefaultFormatter.apply(this, arguments);
-  this.ids  = {};
+  CommonFormatter.apply(this, arguments);
+  this.ids = {};
 }
 
 util.inherits(AMDFormatter, DefaultFormatter);
@@ -30,12 +31,15 @@ AMDFormatter.prototype.transform = function (ast) {
 
   // build an array of module names
 
-  var names = [t.literal("exports")].concat(this.buildDependencyLiterals());
+  var names = [t.literal("exports")];
+  if (this.passModuleArg) names.push(t.literal("module"));
+  names = names.concat(this.buildDependencyLiterals());
   names = t.arrayExpression(names);
 
   // build up define container
 
   var params = _.values(this.ids);
+  if (this.passModuleArg) params.unshift(t.identifier("module"));
   params.unshift(t.identifier("exports"));
 
   var container = t.functionExpression(null, params, t.blockStatement(body));
@@ -96,6 +100,14 @@ AMDFormatter.prototype.importSpecifier = function (specifier, node, nodes) {
   ]));
 };
 
+AMDFormatter.prototype.exportDeclaration = function (node) {
+  if (node.default && !this.noInteropExport) {
+    this.passModuleArg = true;
+  }
+
+  CommonFormatter.prototype.exportDeclaration.apply(this, arguments);
+};
+
 AMDFormatter.prototype.exportSpecifier = function (specifier, node, nodes) {
   var self = this;
   return this._exportSpecifier(function () {

lib/6to5/transformation/modules/common-strict.js

@@ -0,0 +1 @@
+module.exports = require("./_strict")(require("./common"));

lib/6to5/transformation/modules/common.js

@@ -61,7 +61,7 @@ CommonJSFormatter.prototype.importDeclaration = function (node, nodes) {
 };
 
 CommonJSFormatter.prototype.exportDeclaration = function (node, nodes) {
-  if (node.default) {
+  if (node.default && !this.noInteropRequire && !this.noInteropExport) {
     var declar = node.declaration;
     var assign;
 
@@ -83,10 +83,12 @@ CommonJSFormatter.prototype.exportDeclaration = function (node, nodes) {
       // this export isn't a function so we can't hoist it to the top so we need to set it
       // at the very end of the file with something like:
       //
-      //   module.exports = Object.assign(exports["default"], exports)
+      //   module.exports = _extends(exports["default"], exports)
       //
 
-      assign = util.template("common-export-default-assign", true);
+      assign = util.template("common-export-default-assign", {
+        EXTENDS_HELPER: this.file.addHelper("extends")
+      }, true);
       assign._blockHoist = 0;
 
       nodes.push(assign);

lib/6to5/transformation/modules/umd-strict.js

@@ -0,0 +1 @@
+module.exports = require("./_strict")(require("./umd"));

lib/6to5/transformation/modules/umd.js

@@ -25,22 +25,44 @@ UMDFormatter.prototype.transform = function (ast) {
   // factory
 
   var ids  = _.values(this.ids);
-  var args = [t.identifier("exports")].concat(ids);
+  var args = [t.identifier("exports")];
+  if (this.passModuleArg) args.push(t.identifier("module"));
+  args = args.concat(ids);
 
   var factory = t.functionExpression(null, args, t.blockStatement(body));
 
-  // runner
+  // amd
+
+  var defineArgs = [t.literal("exports")];
+  if (this.passModuleArg) defineArgs.push(t.literal("module"));
+  defineArgs = defineArgs.concat(names);
+  defineArgs = [t.arrayExpression(defineArgs)];
+
+  // common
+
+  var testExports = util.template("test-exports");
+  var testModule  = util.template("test-module");
+  var commonTests = this.passModuleArg ? t.logicalExpression("&&", testExports, testModule) : testExports;
+
+  var commonArgs = [t.identifier("exports")];
+  if (this.passModuleArg) commonArgs.push(t.identifier("module"));
+  commonArgs = commonArgs.concat(names.map(function (name) {
+    return t.callExpression(t.identifier("require"), [name]);
+  }));
+
+  // globals
+
+  //var umdArgs = [];
+
+  //
 
-  var defineArgs = [t.arrayExpression([t.literal("exports")].concat(names))];
   var moduleName = this.getModuleName();
   if (moduleName) defineArgs.unshift(t.literal(moduleName));
 
   var runner = util.template("umd-runner-body", {
     AMD_ARGUMENTS: defineArgs,
-
-    COMMON_ARGUMENTS: names.map(function (name) {
-      return t.callExpression(t.identifier("require"), [name]);
-    })
+    COMMON_TEST: commonTests,
+    COMMON_ARGUMENTS: commonArgs
   });
 
   //

lib/6to5/transformation/templates/class-super-constructor-call-loose.js

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

lib/6to5/transformation/templates/class-super-constructor-call.js

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

lib/6to5/transformation/templates/common-export-default-assign.js

@@ -1 +1 @@
-module.exports = Object.assign(exports["default"], exports);
+module.exports = EXTENDS_HELPER(exports["default"], exports);

lib/6to5/transformation/templates/exports-wildcard.js

@@ -1,7 +0,0 @@
-(function (obj) {
-  for (var i in obj) {
-    if (exports[i] !== undefined) {
-      exports[i] = obj[i];
-    }
-  }
-})

lib/6to5/transformation/templates/extends.js

@@ -0,0 +1,9 @@
+(function (target) {
+  for (var i = 1; i < arguments.length; i++) {
+    var source = arguments[i];
+    for (var key in source) {
+      target[key] = source[key];
+    }
+  }
+  return target;
+})

lib/6to5/transformation/templates/for-of-loose.js

@@ -0,0 +1,13 @@
+for (var LOOP_OBJECT = OBJECT,
+         IS_ARRAY = Array.isArray(LOOP_OBJECT),
+         INDEX = 0,
+         LOOP_OBJECT = IS_ARRAY ? LOOP_OBJECT : LOOP_OBJECT[Symbol.iterator]();;) {
+  if (IS_ARRAY) {
+    if (INDEX >= LOOP_OBJECT.length) break;
+    ID = LOOP_OBJECT[INDEX++];
+  } else {
+    INDEX = LOOP_OBJECT.next();
+    if (INDEX.done) break;
+    ID = INDEX.value;
+  }
+}

lib/6to5/transformation/templates/get.js

@@ -0,0 +1,23 @@
+(function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+
+    if (getter === undefined) {
+      return undefined;
+    }
+
+    return getter.call(receiver);
+  }
+});

lib/6to5/transformation/templates/inherits.js

@@ -1,14 +1,14 @@
-(function (child, parent) {
-  if (typeof parent !== "function" && parent !== null) {
-    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+(function (subClass, superClass) {
+  if (typeof superClass !== "function" && superClass !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
   }
-  child.prototype = Object.create(parent && parent.prototype, {
+  subClass.prototype = Object.create(superClass && superClass.prototype, {
     constructor: {
-      value: child,
+      value: subClass,
       enumerable: false,
       writable: true,
       configurable: true
     }
   });
-  if (parent) child.__proto__ = parent;
+  if (superClass) subClass.__proto__ = superClass;
 })

lib/6to5/transformation/templates/object-define-properties-closure.js

@@ -1,5 +0,0 @@
-
-(function (KEY) {
-  CONTENT;
-  return KEY;
-})(OBJECT);

lib/6to5/transformation/templates/object-define-properties.js

@@ -1 +0,0 @@
-Object.defineProperties(OBJECT, PROPS);

lib/6to5/transformation/templates/rest.js

@@ -1,3 +1,3 @@
 for (var KEY = START; KEY < ARGUMENTS.length; KEY++) {
-  ARRAY[$__0] = ARGUMENTS[KEY];
+  ARRAY[ARRAY_KEY] = ARGUMENTS[KEY];
 }

lib/6to5/transformation/templates/tagged-template-literal-loose.js

@@ -0,0 +1,4 @@
+(function (strings, raw) {
+  strings.raw = raw;
+  return strings;
+});

lib/6to5/transformation/templates/test-exports.js

@@ -0,0 +1 @@
+typeof exports !== "undefined"

lib/6to5/transformation/templates/test-module.js

@@ -0,0 +1 @@
+typeof module !== "undefined"

lib/6to5/transformation/templates/umd-runner-body.js

@@ -1,7 +1,7 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(AMD_ARGUMENTS, factory);
-  } else if (typeof exports !== "undefined") {
-    factory(exports, COMMON_ARGUMENTS);
+  } else if (COMMON_TEST) {
+    factory(COMMON_ARGUMENTS);
   }
 });

lib/6to5/transformation/transform.js

@@ -31,17 +31,19 @@ transform._ensureTransformerNames = function (type, keys) {
 transform.transformers = {};
 
 transform.moduleFormatters = {
-  common: require("./modules/common"),
-  system: require("./modules/system"),
-  ignore: require("./modules/ignore"),
-  amd:    require("./modules/amd"),
-  umd:    require("./modules/umd")
+  commonStrict: require("./modules/common-strict"),
+  umdStrict:    require("./modules/umd-strict"),
+  amdStrict:    require("./modules/amd-strict"),
+  common:       require("./modules/common"),
+  system:       require("./modules/system"),
+  ignore:       require("./modules/ignore"),
+  amd:          require("./modules/amd"),
+  umd:          require("./modules/umd")
 };
 
 _.each({
-  // spec
-  specBlockHoistFunctions:   require("./transformers/spec-block-hoist-functions"),
   specNoForInOfAssignment:   require("./transformers/spec-no-for-in-of-assignment"),
+  specSetters:               require("./transformers/spec-setters"),
 
   // playground
   methodBinding:             require("./transformers/playground-method-binding"),
@@ -59,13 +61,12 @@ _.each({
   arrowFunctions:            require("./transformers/es6-arrow-functions"),
   classes:                   require("./transformers/es6-classes"),
 
-  computedPropertyNames:     require("./transformers/es6-computed-property-names"),
-
   objectSpread:              require("./transformers/es7-object-spread"),
   exponentiationOperator:    require("./transformers/es7-exponentiation-operator"),
   spread:                    require("./transformers/es6-spread"),
   templateLiterals:          require("./transformers/es6-template-literals"),
   propertyMethodAssignment:  require("./transformers/es6-property-method-assignment"),
+  computedPropertyNames:     require("./transformers/es6-computed-property-names"),
   destructuring:             require("./transformers/es6-destructuring"),
   defaultParameters:         require("./transformers/es6-default-parameters"),
   forOf:                     require("./transformers/es6-for-of"),

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

@@ -3,36 +3,11 @@ var util     = require("../../util");
 var t        = require("../../types");
 
 exports.ClassDeclaration = function (node, parent, file, scope) {
-  var closure = true;
-  if (t.isProgram(parent) || t.isBlockStatement(parent)) {
-    closure = false;
-  }
-
-  var factory = new Class(node, file, scope, closure);
-  var newNode = factory.run();
-  if (factory.closure) {
-    if (closure) {
-      // declaration in an expression context...
-      // export default class Foo {}
-      scope.push({
-        kind: "var",
-        key: node.id.key,
-        id: node.id
-      });
-      return t.assignmentExpression("=", node.id, newNode);
-    } else {
-      // has a super class or PrivateDeclaration etc
-      return t.variableDeclaration("let", [
-        t.variableDeclarator(node.id, newNode)
-      ]);
-    }
-  } else {
-    return newNode;
-  }
+  return new Class(node, file, scope, true).run();
 };
 
 exports.ClassExpression = function (node, parent, file, scope) {
-  return new Class(node, file, scope, true).run();
+  return new Class(node, file, scope, false).run();
 };
 
 /**
@@ -44,11 +19,11 @@ exports.ClassExpression = function (node, parent, file, scope) {
  * @param {Boolean} closure
  */
 
-function Class(node, file, scope, closure) {
-  this.closure = closure;
-  this.scope   = scope;
-  this.node    = node;
-  this.file    = file;
+function Class(node, file, scope, isStatement) {
+  this.isStatement = isStatement;
+  this.scope       = scope;
+  this.node        = node;
+  this.file        = file;
 
   this.hasInstanceMutators = false;
   this.hasStaticMutators   = false;
@@ -58,6 +33,7 @@ function Class(node, file, scope, closure) {
   this.hasConstructor     = false;
   this.className          = node.id || file.generateUidIdentifier("class", scope);
   this.superName          = node.superClass;
+  this.isLoose            = file.isLoose("classes");
 }
 
 /**
@@ -75,25 +51,32 @@ Class.prototype.run = function () {
 
   var body = this.body = [];
 
-  var constructor = t.functionExpression(null, [], t.blockStatement([]));
-  if (this.node.id) constructor.id = className;
+  var constructor;
+  if (this.node.id) {
+    constructor = t.functionDeclaration(className, [], t.blockStatement([]));
+    body.push(constructor);
+  } else {
+    constructor = t.functionExpression(null, [], t.blockStatement([]));
+    body.push(t.variableDeclaration("var", [
+      t.variableDeclarator(className, constructor)
+    ]));
+  }
   this.constructor = constructor;
 
-  body.push(t.variableDeclaration("let", [
-    t.variableDeclarator(className, constructor)
-  ]));
+  var closureParams = [];
+  var closureArgs = [];
 
   //
 
   if (superName) {
-    this.closure = true;
+    closureArgs.push(superName);
 
-    // so we're only evaluating it once
-    var superRef = this.scope.generateUidBasedOnNode(superName, this.file);
-    body.unshift(t.variableDeclaration("var", [
-      t.variableDeclarator(superRef, superName)
-    ]));
-    superName = superRef;
+    if (!t.isIdentifier(superName)) {
+      var superRef = this.scope.generateUidBasedOnNode(superName, this.file);
+      superName = superRef;
+    }
+
+    closureParams.push(superName);
 
     this.superName = superName;
     body.push(t.expressionStatement(t.callExpression(file.addHelper("inherits"), [className, superName])));
@@ -103,19 +86,25 @@ Class.prototype.run = function () {
 
   t.inheritsComments(body[0], this.node);
 
-  if (this.closure) {
-    if (body.length === 1) {
-      // only a constructor so no need for a closure container
-      return constructor;
-    } else {
-      body.push(t.returnStatement(className));
-      return t.callExpression(
-        t.functionExpression(null, [], t.blockStatement(body)),
-        []
-      );
-    }
+  var init;
+
+  if (body.length === 1) {
+    // only a constructor so no need for a closure container
+    init = t.toExpression(constructor);
   } else {
-    return body;
+    body.push(t.returnStatement(className));
+    init = t.callExpression(
+      t.functionExpression(null, closureParams, t.blockStatement(body)),
+      closureArgs
+    );
+  }
+
+  if (this.isStatement) {
+    return t.variableDeclaration("let", [
+      t.variableDeclarator(className, init)
+    ]);
+  } else {
+    return init;
   }
 };
 
@@ -129,27 +118,31 @@ Class.prototype.buildBody = function () {
   var superName   = this.superName;
   var classBody   = this.node.body.body;
   var body        = this.body;
-  var self        = this;
 
   for (var i in classBody) {
     var node = classBody[i];
     if (t.isMethodDefinition(node)) {
-      self.replaceInstanceSuperReferences(node);
+      this.replaceInstanceSuperReferences(node);
 
       if (node.key.name === "constructor") {
-        self.pushConstructor(node);
+        this.pushConstructor(node);
       } else {
-        self.pushMethod(node);
+        this.pushMethod(node);
       }
     } else if (t.isPrivateDeclaration(node)) {
-      self.closure = true;
+      this.closure = true;
       body.unshift(node);
     }
   }
 
+  // we have no constructor, we have a super, and the super doesn't appear to be falsy
   if (!this.hasConstructor && superName && !t.isFalsyExpression(superName)) {
-    constructor.body.body.push(util.template("class-super-constructor-call", {
-      SUPER_NAME: superName
+    var defaultConstructorTemplate = "class-super-constructor-call";
+    if (this.isLoose) defaultConstructorTemplate += "-loose";
+
+    constructor.body.body.push(util.template(defaultConstructorTemplate, {
+      CLASS_NAME: className,
+      SUPER_NAME: this.superName
     }, true));
   }
 
@@ -157,15 +150,11 @@ Class.prototype.buildBody = function () {
   var staticProps;
 
   if (this.hasInstanceMutators) {
-    var protoId = util.template("prototype-identifier", {
-      CLASS_NAME: className
-    });
-
-    instanceProps = util.buildDefineProperties(this.instanceMutatorMap, protoId);
+    instanceProps = util.buildDefineProperties(this.instanceMutatorMap);
   }
 
   if (this.hasStaticMutators) {
-    staticProps = util.buildDefineProperties(this.staticMutatorMap, className);
+    staticProps = util.buildDefineProperties(this.staticMutatorMap);
   }
 
   if (instanceProps || staticProps) {
@@ -190,41 +179,74 @@ Class.prototype.pushMethod = function (node) {
   var methodName = node.key;
 
   var kind = node.kind;
+  var mutatorMap = this.instanceMutatorMap;
+  if (node.static) {
+    this.hasStaticMutators = true;
+    mutatorMap = this.staticMutatorMap;
+  } else {
+    this.hasInstanceMutators = true;
+  }
 
   if (kind === "") {
-    // method
+    if (this.isLoose) {
+      // use assignments instead of define properties for loose classes
 
-    var className = this.className;
-    if (!node.static) className = t.memberExpression(className, t.identifier("prototype"));
-    methodName = t.memberExpression(className, methodName, node.computed);
+      var className = this.className;
+      if (!node.static) className = t.memberExpression(className, t.identifier("prototype"));
+      methodName = t.memberExpression(className, methodName, node.computed);
 
-    var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
-    t.inheritsComments(expr, node);
-    this.body.push(expr);
-  } else {
-    // mutator
-    var mutatorMap = this.instanceMutatorMap;
-    if (node.static) {
-      this.hasStaticMutators = true;
-      mutatorMap = this.staticMutatorMap;
-    } else {
-      this.hasInstanceMutators = true;
+      var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
+      t.inheritsComments(expr, node);
+      this.body.push(expr);
+      return;
     }
-    util.pushMutatorMap(mutatorMap, methodName, kind, node);
+
+    kind = "value";
   }
+
+  util.pushMutatorMap(mutatorMap, methodName, kind, node.computed, node);
 };
 
 /**
- * Given a `methodNode`, produce a `MemberExpression` super class reference.
+ * Gets a node representing the super class value of the named property.
  *
- * @param {Node} methodNode MethodDefinition
- * @param {Node} node Identifier
- * @param {Node} parent
+ * @example
+ *
+ *   _get(Object.getPrototypeOf(CLASS.prototype), "METHOD", this)
+ *
+ * @param {Node} property
+ * @param {boolean} isStatic
+ * @param {boolean} isComputed
  *
  * @returns {Node}
  */
 
-Class.prototype.superIdentifier = function (methodNode, id, parent) {
+Class.prototype.superProperty = function (property, isStatic, isComputed, thisExpression) {
+  return t.callExpression(
+    this.file.addHelper("get"),
+    [
+      t.callExpression(
+        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+        [
+          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
+        ]
+      ),
+      isComputed ? property : t.literal(property.name),
+      thisExpression
+    ]
+  );
+};
+
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @param {Object} id
+ * @param {Object} parent
+ * @returns {Object}
+ */
+
+Class.prototype.looseSuperProperty = function (methodNode, id, parent) {
   var methodName = methodNode.key;
   var superName  = this.superName || t.identifier("Function");
 
@@ -264,23 +286,112 @@ Class.prototype.superIdentifier = function (methodNode, id, parent) {
 
 Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
   var method = methodNode.value;
-  var self = this;
+  var self   = this;
 
-  traverse(method, {
-    enter: function (node, parent) {
-      if (t.isIdentifier(node, { name: "super" })) {
-        return self.superIdentifier(methodNode, node, parent);
-      } else if (t.isCallExpression(node)) {
-        var callee = node.callee;
+  var topLevelThisReference;
+
+  traverseLevel(method, true);
+
+  if (topLevelThisReference) {
+    method.body.body.unshift(t.variableDeclaration("var", [
+      t.variableDeclarator(topLevelThisReference, t.thisExpression())
+    ]));
+  }
+
+  function traverseLevel(node, topLevel) {
+    traverse(node, {
+      enter: function (node, parent) {
+        if (t.isFunction(node) && !t.isArrowFunctionExpression(node)) {
+          // we need to call traverseLevel again so we're context aware
+          traverseLevel(node, false);
+          return this.skip();
+        }
+
+        var getThisReference = function () {
+          if (topLevel) {
+            // top level so `this` is the instance
+            return t.thisExpression();
+          } else {
+            // not in the top level so we need to create a reference
+            return topLevelThisReference = topLevelThisReference || self.file.generateUidIdentifier("this");
+          }
+        };
+
+        var callback = specHandle;
+        if (self.isLoose) callback = looseHandle;
+        return callback(getThisReference, node, parent);
+      }
+    });
+  }
+
+  function looseHandle(getThisReference, node, parent) {
+    if (t.isIdentifier(node, { name: "super" })) {
+      return self.looseSuperProperty(methodNode, node, parent);
+    } else if (t.isCallExpression(node)) {
+      var callee = node.callee;
+      if (!t.isMemberExpression(callee)) return;
+      if (callee.object.name !== "super") return;
+
+      // super.test(); -> ClassName.prototype.MethodName.call(this);
+      t.appendToMemberExpression(callee, t.identifier("call"));
+      node.arguments.unshift(getThisReference());
+    }
+  }
+
+  function specHandle(getThisReference, node, parent) {
+    var property;
+    var computed;
+    var args;
+
+    if (t.isIdentifier(node, { name: "super" })) {
+      if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
+        throw self.file.errorWithNode(node, "illegal use of bare super");
+      }
+    } else if (t.isCallExpression(node)) {
+      var callee = node.callee;
+      if (t.isIdentifier(callee, { name: "super" })) {
+        // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
+        property = methodNode.key;
+        computed = methodNode.computed;
+        args = node.arguments;
+      } else {
         if (!t.isMemberExpression(callee)) return;
         if (callee.object.name !== "super") return;
 
-        // super.test(); -> ClassName.prototype.MethodName.call(this);
-        t.appendToMemberExpression(callee, t.identifier("call"));
-        node.arguments.unshift(t.thisExpression());
+        // super.test(); -> _get(Object.getPrototypeOf(ClassName.prototype), "test", this).call(this);
+        property = callee.property;
+        computed = callee.computed;
+        args = node.arguments;
       }
+    } else if (t.isMemberExpression(node)) {
+      if (!t.isIdentifier(node.object, { name: "super" })) return;
+
+      // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
+      property = node.property;
+      computed = node.computed;
     }
-  });
+
+    if (!property) return;
+
+    var thisReference = getThisReference();
+    var superProperty = self.superProperty(property, methodNode.static, computed, thisReference);
+    if (args) {
+      if (args.length === 1 && t.isSpreadElement(args[0])) {
+        // super(...arguments);
+        return t.callExpression(
+          t.memberExpression(superProperty, t.identifier("apply")),
+          [thisReference, args[0].argument]
+        );
+      } else {
+        return t.callExpression(
+          t.memberExpression(superProperty, t.identifier("call")),
+          [thisReference].concat(args)
+        );
+      }
+    } else {
+      return superProperty;
+    }
+  }
 };
 
 /**
@@ -290,7 +401,7 @@ Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
  */
 
 Class.prototype.pushConstructor = function (method) {
-  if (method.kind !== "") {
+  if (method.kind) {
     throw this.file.errorWithNode(method, "illegal kind for constructor method");
   }
 
@@ -302,8 +413,9 @@ Class.prototype.pushConstructor = function (method) {
   t.inherits(construct, fn);
   t.inheritsComments(construct, method);
 
-  construct.defaults = fn.defaults;
-  construct.params   = fn.params;
-  construct.body     = fn.body;
-  construct.rest     = fn.rest;
+  construct._ignoreUserWhitespace = true;
+  construct.defaults              = fn.defaults;
+  construct.params                = fn.params;
+  construct.body                  = fn.body;
+  construct.rest                  = fn.rest;
 };

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

@@ -2,29 +2,66 @@ var t = require("../../types");
 
 exports.ObjectExpression = function (node, parent, file, scope) {
   var hasComputed = false;
-  var prop;
-  var key;
-  var i;
 
-  for (i in node.properties) {
-    hasComputed = t.isProperty(node.properties[i], { computed: true });
+  for (var i in node.properties) {
+    hasComputed = t.isProperty(node.properties[i], { computed: true, kind: "init" });
     if (hasComputed) break;
   }
 
   if (!hasComputed) return;
 
+  var initProps = [];
   var objId = scope.generateUidBasedOnNode(parent, file);
 
+  //
+
   var body = [];
   var container = t.functionExpression(null, [], t.blockStatement(body));
   container._aliasFunction = true;
 
+  //
+
+  var callback = spec;
+  if (file.isLoose("computedPropertyNames")) callback = loose;
+
+  var result = callback(node, body, objId, initProps, file);
+  if (result) return result;
+
+  //
+
+  body.unshift(t.variableDeclaration("var", [
+    t.variableDeclarator(objId, t.objectExpression(initProps))
+  ]));
+
+  body.push(t.returnStatement(objId));
+
+  return t.callExpression(container, []);
+};
+
+var loose = function (node, body, objId) {
+  for (var i in node.properties) {
+    var prop = node.properties[i];
+
+    body.push(t.expressionStatement(
+      t.assignmentExpression(
+        "=",
+        t.memberExpression(objId, prop.key, prop.computed),
+        prop.value
+      )
+    ));
+  }
+};
+
+var spec = function (node, body, objId, initProps, file) {
   var props = node.properties;
+  var prop, key;
 
   // normalise key
 
-  for (i in props) {
+  for (var i in props) {
     prop = props[i];
+    if (prop.kind !== "init") continue;
+
     key = prop.key;
 
     if (!prop.computed && t.isIdentifier(key)) {
@@ -34,7 +71,6 @@ exports.ObjectExpression = function (node, parent, file, scope) {
 
   // add all non-computed properties and `__proto__` properties to the initializer
 
-  var initProps = [];
   var broken = false;
 
   for (i in props) {
@@ -44,7 +80,7 @@ exports.ObjectExpression = function (node, parent, file, scope) {
       broken = true;
     }
 
-    if (!broken || t.isLiteral(t.toComputedKey(prop, prop.key), { value: "__proto__" })) {
+    if (prop.kind !== "init" || !broken || t.isLiteral(t.toComputedKey(prop, prop.key), { value: "__proto__" })) {
       initProps.push(prop);
       props[i] = null;
     }
@@ -84,14 +120,4 @@ exports.ObjectExpression = function (node, parent, file, scope) {
       return first;
     }
   }
-
-  //
-
-  body.unshift(t.variableDeclaration("var", [
-    t.variableDeclarator(objId, t.objectExpression(initProps))
-  ]));
-
-  body.push(t.returnStatement(objId));
-
-  return t.callExpression(container, []);
 };

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

@@ -1,7 +1,6 @@
 var traverse = require("../../traverse");
 var util     = require("../../util");
 var t        = require("../../types");
-var _        = require("lodash");
 
 exports.Function = function (node, parent, file, scope) {
   if (!node.defaults || !node.defaults.length) return;
@@ -15,6 +14,23 @@ exports.Function = function (node, parent, file, scope) {
   var i;
   var def;
 
+  var checkTDZ = function (ids) {
+    var check = function (node, parent) {
+      if (!t.isIdentifier(node) || !t.isReferenced(node, parent)) return;
+
+      if (ids.indexOf(node.name) >= 0) {
+        throw file.errorWithNode(node, "Temporal dead zone - accessing a variable before it's initialized");
+      }
+
+      if (scope.has(node.name, true)) {
+        iife = true;
+      }
+    };
+
+    check(def, node);
+    traverse(def, { enter: check });
+  };
+
   for (i in node.defaults) {
     def = node.defaults[i];
     if (!def) continue;
@@ -23,22 +39,10 @@ exports.Function = function (node, parent, file, scope) {
 
     // temporal dead zone check - here we prevent accessing of params that
     // are to the right - ie. uninitialized parameters
-    _.each(ids.slice(i), function (ids) {
-      var check = function (node, parent) {
-        if (!t.isIdentifier(node) || !t.isReferenced(node, parent)) return;
-
-        if (ids.indexOf(node.name) >= 0) {
-          throw file.errorWithNode(node, "Temporal dead zone - accessing a variable before it's initialized");
-        }
-
-        if (scope.has(node.name)) {
-          iife = true;
-        }
-      };
-
-      check(def, node);
-      traverse(def, { enter: check });
-    });
+    var rightIds = ids.slice(i);
+    for (i in rightIds) {
+      checkTDZ(rightIds[i]);
+    }
 
     // we're accessing a variable that's already defined within this function
     var has = scope.get(param.name);

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

@@ -134,7 +134,7 @@ var pushPattern = function (opts) {
   var file = opts.file;
   var scope = opts.scope;
 
-  if (!t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
+  if (!t.isArrayExpression(parentId) && !t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
     var key = scope.generateUidBasedOnNode(parentId, file);
 
     nodes.push(t.variableDeclaration("var", [
@@ -300,10 +300,17 @@ exports.VariableDeclaration = function (node, parent, file, scope) {
       file:    file,
       scope:   scope
     };
+
     if (t.isPattern(pattern) && patternId) {
       pushPattern(opts);
+
+      if (+i !== node.declarations.length - 1) {
+        // we aren't the last declarator so let's just make the
+        // last transformed node inherit from us
+        t.inherits(nodes[nodes.length - 1], declar);
+      }
     } else {
-      nodes.push(buildVariableAssign(opts, declar.id, declar.init));
+      nodes.push(t.inherits(buildVariableAssign(opts, declar.id, declar.init), declar));
     }
   }
 

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

@@ -2,15 +2,79 @@ var util = require("../../util");
 var t    = require("../../types");
 
 exports.ForOfStatement = function (node, parent, file, scope) {
+  var callback = spec;
+  if (file.isLoose("forOf")) callback = loose;
+
+  var build  = callback(node, parent, file, scope);
+  var declar = build.declar;
+  var loop   = build.loop;
+  var block  = loop.body;
+
+  // inherit comments from the original loop
+  t.inheritsComments(loop, node);
+
+  // ensure that it's a block so we can take all it's statemetns
+  t.ensureBlock(node);
+
+  // add the value declaration to the new loop body
+  if (declar){
+    if (build.shouldUnshift) {
+      block.body.unshift(declar);
+    } else {
+      block.body.push(declar);
+    }
+  }
+
+  // push the rest of the original loop body onto our new body
+  block.body = block.body.concat(node.body.body);
+
+  return loop;
+};
+
+var loose = function (node, parent, file, scope) {
+  var left = node.left;
+  var declar, id;
+
+  if (t.isIdentifier(left) || t.isPattern(left)) {
+    // for (i of test), for ({ i } of test)
+    id = left;
+  } else if (t.isVariableDeclaration(left)) {
+    // for (var i of test)
+    id = left.declarations[0].id;
+    declar = t.variableDeclaration(left.kind, [
+      t.variableDeclarator(id)
+    ]);
+  } else {
+    throw file.errorWithNode(left, "Unknown node type " + left.type + " in ForOfStatement");
+  }
+
+  var loop = util.template("for-of-loose", {
+    LOOP_OBJECT:  file.generateUidIdentifier("iterator", scope),
+    IS_ARRAY:     file.generateUidIdentifier("isArray", scope),
+    OBJECT:       node.right,
+    INDEX:        file.generateUidIdentifier("i", scope),
+    ID:           id
+  });
+
+  return {
+    shouldUnshift: true,
+    declar:        declar,
+    loop:          loop
+  };
+};
+
+var spec = function (node, parent, file, scope) {
   var left = node.left;
   var declar;
 
   var stepKey   = file.generateUidIdentifier("step", scope);
   var stepValue = t.memberExpression(stepKey, t.identifier("value"));
 
-  if (t.isIdentifier(left)) {
+  if (t.isIdentifier(left) || t.isPattern(left)) {
+    // for (i of test), for ({ i } of test)
     declar = t.expressionStatement(t.assignmentExpression("=", left, stepValue));
   } else if (t.isVariableDeclaration(left)) {
+    // for (var i of test)
     declar = t.variableDeclaration(left.kind, [
       t.variableDeclarator(left.declarations[0].id, stepValue)
     ]);
@@ -18,18 +82,14 @@ exports.ForOfStatement = function (node, parent, file, scope) {
     throw file.errorWithNode(left, "Unknown node type " + left.type + " in ForOfStatement");
   }
 
-  var node2 = util.template("for-of", {
+  var loop = util.template("for-of", {
     ITERATOR_KEY: file.generateUidIdentifier("iterator", scope),
     STEP_KEY:     stepKey,
     OBJECT:       node.right
   });
 
-  t.inheritsComments(node2, node);
-  t.ensureBlock(node);
-
-  var block = node2.body;
-  block.body.push(declar);
-  block.body = block.body.concat(node.body.body);
-
-  return node2;
+  return {
+    declar: declar,
+    loop:   loop
+  };
 };

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

@@ -1,3 +1,9 @@
+var regenerator = require("regenerator");
+
 exports.ast = {
-  before: require("regenerator").transform
+  before: function (ast, file) {
+    regenerator.transform(ast, {
+      includeRuntime: file.opts.includeRegenerator && "if used"
+    });
+  }
 };

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

@@ -250,10 +250,11 @@ LetScoping.prototype.getInfo = function () {
     declar = block.body[i];
     if (!isLet(declar, block)) continue;
 
-    _.each(t.getIds(declar, true), function (id, key) {
-      duplicates(id, key);
+    var declars = t.getIds(declar, true);
+    for (var key in declars) {
+      duplicates(declars[key], key);
       opts.keys.push(key);
-    });
+    }
   }
 
   return opts;

lib/6to5/transformation/transformers/es6-property-method-assignment.js

@@ -46,14 +46,14 @@ exports.Property = function (node, parent, file, scope) {
   }
 };
 
-exports.ObjectExpression = function (node, parent, file, scope) {
+exports.ObjectExpression = function (node) {
   var mutatorMap = {};
   var hasAny = false;
 
   node.properties = node.properties.filter(function (prop) {
     if (prop.kind === "get" || prop.kind === "set") {
       hasAny = true;
-      util.pushMutatorMap(mutatorMap, prop.key, prop.kind, prop.value);
+      util.pushMutatorMap(mutatorMap, prop.key, prop.kind, prop.computed, prop.value);
       return false;
     } else {
       return true;
@@ -62,21 +62,8 @@ exports.ObjectExpression = function (node, parent, file, scope) {
 
   if (!hasAny) return;
 
-  if (node.properties.length) {
-    var objId = scope.generateUidBasedOnNode(parent, file);
-
-    return util.template("object-define-properties-closure", {
-      KEY: objId,
-      OBJECT: node,
-      CONTENT: util.template("object-define-properties", {
-        OBJECT: objId,
-        PROPS:  util.buildDefineProperties(mutatorMap)
-      })
-    });
-  } else {
-    return util.template("object-define-properties", {
-      OBJECT: node,
-      PROPS:  util.buildDefineProperties(mutatorMap)
-    });
-  }
+  return t.callExpression(
+    t.memberExpression(t.identifier("Object"), t.identifier("defineProperties")),
+    [node, util.buildDefineProperties(mutatorMap)]
+  );
 };

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

@@ -12,6 +12,14 @@ exports.Function = function (node, parent, file) {
   var argsId = t.identifier("arguments");
   argsId._ignoreAliasFunctions = true;
 
+  var start = t.literal(node.params.length);
+  var key = file.generateUidIdentifier("key");
+
+  var arrKey = key;
+  if (node.params.length) {
+    arrKey = t.binaryExpression("-", arrKey, start);
+  }
+
   node.body.body.unshift(
     t.variableDeclaration("var", [
       t.variableDeclarator(rest, t.arrayExpression([]))
@@ -19,9 +27,10 @@ exports.Function = function (node, parent, file) {
 
     util.template("rest", {
       ARGUMENTS: argsId,
-      START: t.literal(node.params.length),
+      ARRAY_KEY: arrKey,
+      START: start,
       ARRAY: rest,
-      KEY: file.generateUidIdentifier("key")
+      KEY: key
     })
   );
 };

lib/6to5/transformation/transformers/es6-template-literals.js

@@ -17,10 +17,12 @@ exports.TaggedTemplateExpression = function (node, parent, file) {
     raw.push(t.literal(elem.value.raw));
   }
 
-  args.push(t.callExpression(file.addHelper("tagged-template-literal"), [
-    t.arrayExpression(strings),
-    t.arrayExpression(raw)
-  ]));
+  strings = t.arrayExpression(strings);
+  raw = t.arrayExpression(raw);
+
+  var templateName = "tagged-template-literal";
+  if (file.isLoose("templateLiterals")) templateName += "-loose";
+  args.push(t.callExpression(file.addHelper(templateName), [strings, raw]));
 
   args = args.concat(quasi.expressions);
 

lib/6to5/transformation/transformers/es7-object-spread.js

@@ -4,7 +4,7 @@ var t = require("../../types");
 
 exports.experimental = true;
 
-exports.ObjectExpression = function (node) {
+exports.ObjectExpression = function (node, parent, file) {
   var hasSpread = false;
   var i;
   var prop;
@@ -42,5 +42,5 @@ exports.ObjectExpression = function (node) {
     args.unshift(t.objectExpression([]));
   }
 
-  return t.callExpression(t.memberExpression(t.identifier("Object"), t.identifier("assign")), args);
+  return t.callExpression(file.addHelper("extends"), args);
 };

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

@@ -8,6 +8,15 @@ var coreHas = function (node) {
   return node.name !== "_" && _.has(core, node.name);
 };
 
+var ALIASABLE_CONSTRUCTORS = [
+  "Symbol",
+  "Promise",
+  "Map",
+  "WeakMap",
+  "Set",
+  "WeakSet"
+];
+
 exports.optional = true;
 
 exports.ast = {
@@ -31,8 +40,8 @@ exports.ast = {
             this.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && coreHas(node)) {
-          // new Promise -> new _core.Promise
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && _.contains(ALIASABLE_CONSTRUCTORS, node.name)) {
+          // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)

lib/6to5/transformation/transformers/optional-proto-to-assign.js

@@ -1,8 +1,6 @@
 var t = require("../../types");
 var _ = require("lodash");
 
-var OBJECT_ASSIGN_MEMBER = t.memberExpression(t.identifier("Object"), t.identifier("assign"));
-
 var isProtoKey = function (node) {
   return t.isLiteral(t.toComputedKey(node, node.key), { value: "__proto__" });
 };
@@ -43,7 +41,7 @@ exports.ExpressionStatement = function (node, parent, file) {
   }
 };
 
-exports.ObjectExpression = function (node) {
+exports.ObjectExpression = function (node, parent, file) {
   var proto;
 
   for (var i in node.properties) {
@@ -58,6 +56,6 @@ exports.ObjectExpression = function (node) {
   if (proto) {
     var args = [t.objectExpression([]), proto];
     if (node.properties.length) args.push(node);
-    return t.callExpression(OBJECT_ASSIGN_MEMBER, args);
+    return t.callExpression(file.addHelper("extends"), args);
   }
 };

lib/6to5/transformation/transformers/react.js

@@ -5,6 +5,7 @@
 
 var esutils = require("esutils");
 var t       = require("../../types");
+var _       = require("lodash");
 
 exports.XJSIdentifier = function (node) {
   if (esutils.keyword.isIdentifierName(node.name)) {
@@ -32,12 +33,17 @@ exports.XJSExpressionContainer = function (node) {
 exports.XJSAttribute = {
   exit: function (node) {
     var value = node.value || t.literal(true);
-    return t.property("init", node.name, value);
+    return t.inherits(t.property("init", node.name, value), node);
   }
 };
 
+var isTag = function(tagName) {
+  return (/^[a-z]|\-/).test(tagName);
+};
+
 exports.XJSOpeningElement = {
-  exit: function (node) {
+  exit: function (node, parent, file) {
+    var reactCompat = file.opts.reactCompat;
     var tagExpr = node.name;
     var args = [];
 
@@ -48,17 +54,24 @@ exports.XJSOpeningElement = {
       tagName = tagExpr.value;
     }
 
-    if (tagName && (/[a-z]/.exec(tagName[0]) || tagName.indexOf("-") >= 0)) {
-      args.push(t.literal(tagName));
-    } else {
-      args.push(tagExpr);
+    if (!reactCompat) {
+      if (tagName && isTag(tagName)) {
+        args.push(t.literal(tagName));
+      } else {
+        args.push(tagExpr);
+      }
     }
 
-    var props = node.attributes;
-    if (props.length) {
+    var attribs = node.attributes;
+    if (attribs.length) {
       var _props = [];
       var objs = [];
 
+      // so basically in order to support spread elements we
+      // loop over all the attributes, breaking on spreads
+      // we then push a new object containing all prior attributes
+      // to an array for later processing
+
       var pushProps = function () {
         if (!_props.length) return;
 
@@ -66,8 +79,8 @@ exports.XJSOpeningElement = {
         _props = [];
       };
 
-      while (props.length) {
-        var prop = props.shift();
+      while (attribs.length) {
+        var prop = attribs.shift();
         if (t.isXJSSpreadAttribute(prop)) {
           pushProps();
           objs.push(prop.argument);
@@ -79,24 +92,41 @@ exports.XJSOpeningElement = {
       pushProps();
 
       if (objs.length === 1) {
-        props = objs[0];
+        // only one object
+        attribs = objs[0];
       } else {
+        // looks like we have multiple objects
         if (!t.isObjectExpression(objs[0])) {
           objs.unshift(t.objectExpression([]));
         }
 
-        props = t.callExpression(
+        // spread it
+        attribs = t.callExpression(
           t.memberExpression(t.identifier("React"), t.identifier("__spread")),
           objs
         );
       }
     } else {
-      props = t.literal(null);
+      attribs = t.literal(null);
     }
 
-    args.push(props);
+    args.push(attribs);
+
+    if (reactCompat) {
+      if (tagName && isTag(tagName)) {
+        return t.callExpression(
+          t.memberExpression(
+            t.memberExpression(t.identifier("React"), t.identifier("DOM")),
+            tagExpr,
+            t.isLiteral(tagExpr)
+          ),
+          args
+        );
+      }
+    } else {
+      tagExpr = t.memberExpression(t.identifier("React"), t.identifier("createElement"));
+    }
 
-    tagExpr = t.memberExpression(t.identifier("React"), t.identifier("createElement"));
     return t.callExpression(tagExpr, args);
   }
 };
@@ -109,7 +139,7 @@ exports.XJSElement = {
     for (i in node.children) {
       var child = node.children[i];
 
-      if (t.isLiteral(child)) {
+      if (t.isLiteral(child) && _.isString(child.value)) {
         var lines = child.value.split(/\r\n|\n|\r/);
 
         for (i in lines) {
@@ -119,16 +149,16 @@ exports.XJSElement = {
           var isLastLine = +i === lines.length - 1;
 
           // replace rendered whitespace tabs with spaces
-          var trimmedLine = line.replace(/\t/g, ' ');
+          var trimmedLine = line.replace(/\t/g, " ");
 
           // trim whitespace touching a newline
           if (!isFirstLine) {
-            trimmedLine = trimmedLine.replace(/^[ ]+/, '');
+            trimmedLine = trimmedLine.replace(/^[ ]+/, "");
           }
 
           // trim whitespace touching an endline
           if (!isLastLine) {
-            trimmedLine = trimmedLine.replace(/[ ]+$/, '');
+            trimmedLine = trimmedLine.replace(/[ ]+$/, "");
           }
 
           if (trimmedLine) {
@@ -144,6 +174,10 @@ exports.XJSElement = {
       callExpr.arguments.push(child);
     }
 
+    if (callExpr.arguments.length >= 3) {
+      callExpr._prettyCall = true;
+    }
+
     return t.inherits(callExpr, node);
   }
 };

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

@@ -1,18 +0,0 @@
-var t = require("../../types");
-
-exports.BlockStatement = function (node, parent) {
-  if (t.isFunction(parent)) return;
-
-  node.body = node.body.map(function (node) {
-    if (t.isFunction(node)) {
-      node.type = "FunctionExpression";
-      var declar = t.variableDeclaration("let", [
-        t.variableDeclarator(node.id, node)
-      ]);
-      declar._blockHoist = true;
-      return declar;
-    } else {
-      return node;
-    }
-  });
-};

lib/6to5/transformation/transformers/spec-member-expression-literals.js

@@ -1,5 +1,4 @@
-var esutils = require("esutils");
-var t       = require("../../types");
+var t = require("../../types");
 
 exports.MemberExpression = function (node) {
   var prop = node.property;
@@ -7,7 +6,7 @@ exports.MemberExpression = function (node) {
     // computed literal that is a valid identifier
     node.property = t.identifier(prop.value);
     node.computed = false;
-  } else if (!node.computed && t.isIdentifier(prop) && esutils.keyword.isKeywordES6(prop.name, true)) {
+  } else if (!node.computed && t.isIdentifier(prop) && !t.isValidIdentifier(prop.name)) {
     node.property = t.literal(prop.name);
     node.computed = true;
   }

lib/6to5/transformation/transformers/spec-property-literals.js

@@ -1,5 +1,4 @@
-var esutils = require("esutils");
-var t       = require("../../types");
+var t = require("../../types");
 
 exports.Property = function (node) {
   var key = node.key;
@@ -7,7 +6,7 @@ exports.Property = function (node) {
     // property key is a literal but a valid identifier
     node.key = t.identifier(key.value);
     node.computed = false;
-  } else if (!node.computed && t.isIdentifier(key) && esutils.keyword.isKeywordES6(key.name, true)) {
+  } else if (!node.computed && t.isIdentifier(key) && !t.isValidIdentifier(key.name)) {
     // property key is a keyword
     node.key = t.literal(key.name);
   }

lib/6to5/transformation/transformers/spec-setters.js

@@ -0,0 +1,6 @@
+exports.MethodDefinition =
+exports.Property = function (node, parent, file) {
+  if (node.kind === "set" && node.value.params.length !== 1) {
+    throw file.errorWithNode(node.value, "Setters must have only one parameter");
+  }
+};

lib/6to5/traverse/index.js

@@ -4,15 +4,101 @@ var Scope = require("./scope");
 var t     = require("../types");
 var _     = require("lodash");
 
+function TraversalContext(previousContext) {
+  this.didSkip = false;
+  this.didRemove = false;
+  this.didStop = false;
+  this.didFlatten = previousContext ? previousContext.didFlatten : false;
+}
+
+TraversalContext.prototype.flatten = function () {
+  this.didFlatten = true;
+};
+
+TraversalContext.prototype.remove = function () {
+  this.didRemove = true;
+  this.skip();
+};
+
+TraversalContext.prototype.skip = function () {
+  this.didSkip = true;
+};
+
+TraversalContext.prototype.stop = function () {
+  this.didStop = true;
+  this.skip();
+};
+
+TraversalContext.prototype.maybeReplace = function (result, obj, key, node) {
+  if (result === false) return node;
+  if (result == null) return node;
+
+  var isArray = Array.isArray(result);
+
+  // inherit comments from original node to the first replacement node
+  var inheritTo = result;
+  if (isArray) inheritTo = result[0];
+  if (inheritTo) t.inheritsComments(inheritTo, node);
+
+  // replace the node
+  node = obj[key] = result;
+
+  // we're replacing a statement or block node with an array of statements so we better
+  // ensure that it's a block
+  if (isArray && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
+    t.ensureBlock(obj, key);
+  }
+
+  if (isArray) {
+    this.flatten();
+  }
+
+  return node;
+};
+
+TraversalContext.prototype.visit = function (obj, key, opts, scope, parent) {
+  var node = obj[key];
+  if (!node) return;
+
+  // type is blacklisted
+  if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) return;
+
+  var result;
+  var ourScope = scope;
+  if (t.isScope(node)) ourScope = new Scope(node, scope);
+
+  // enter
+  if (opts.enter) {
+    result = opts.enter.call(this, node, parent, ourScope);
+    node = this.maybeReplace(result, obj, key, node);
+
+    if (this.didRemove) {
+      obj[key] = null;
+      this.flatten();
+    }
+
+    // stop traversal
+    if (this.didSkip) return;
+  }
+
+  // traverse node
+  traverse(node, opts, ourScope);
+
+  // exit
+  if (opts.exit) {
+    result = opts.exit.call(this, node, parent, ourScope);
+    node = this.maybeReplace(result, obj, key, node);
+  }
+};
+
 function traverse(parent, opts, scope) {
   // falsy node
   if (!parent) return;
 
   // array of nodes
-  if (_.isArray(parent)) {
-    _.each(parent, function (node) {
-      traverse(node, opts, scope);
-    });
+  if (Array.isArray(parent)) {
+    for (var i = 0; i < parent.length; i++)
+      traverse(parent[i], opts, scope);
     return;
   }
 
@@ -21,99 +107,21 @@ function traverse(parent, opts, scope) {
   if (!keys) return;
 
   opts = opts || {};
+  var context = null;
 
-  var stopped = false;
-
-  for (var i in keys) {
-    var key = keys[i];
+  for (var j = 0; j < keys.length; j++) {
+    var key = keys[j];
     var nodes = parent[key];
     if (!nodes) continue;
 
-    var flatten = false;
-
-    var handle = function (obj, key) {
-      var node = obj[key];
-      if (!node) return;
-
-      // type is blacklisted
-      if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) return;
-
-      // replace node
-      var maybeReplace = function (result) {
-        if (result === false) return;
-        if (result == null) return;
-
-        var isArray = _.isArray(result);
-
-        // inherit comments from original node to the first replacement node
-        var inheritTo = result;
-        if (isArray) inheritTo = result[0];
-        if (inheritTo) t.inheritsComments(inheritTo, node);
-
-        // replace the node
-        node = obj[key] = result;
-
-        if (isArray) flatten = true;
-
-        // we're replacing a statement or block node with an array of statements so we better
-        // ensure that it's a block
-        if (isArray && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
-          t.ensureBlock(obj, key);
-        }
-      };
-
-      var skipped = false;
-      var removed = false;
-
-      var context = {
-        stop: function () {
-          skipped = stopped = true;
-        },
-
-        skip: function () {
-          skipped = true;
-        },
-
-        remove: function () {
-          this.skip();
-          removed = true;
-        }
-      };
-
-      //
-      var ourScope = scope;
-      if (t.isScope(node)) ourScope = new Scope(node, scope);
-
-      // enter
-      if (opts.enter) {
-        var result = opts.enter.call(context, node, parent, ourScope);
-        maybeReplace(result);
-
-        if (removed) {
-          obj[key] = null;
-          flatten = true;
-        }
-
-        // stop iteration
-        if (skipped) return;
+    if (Array.isArray(nodes)) {
+      for (var k = 0; k < nodes.length; k++) {
+        context = new TraversalContext(context);
+        context.visit(nodes, k, opts, scope, parent);
+        if (context.didStop) return;
       }
 
-      // traverse node
-      traverse(node, opts, ourScope);
-
-      // exit
-      if (opts.exit) {
-        maybeReplace(opts.exit.call(context, node, parent, ourScope));
-      }
-    };
-
-    if (_.isArray(nodes)) {
-      for (i in nodes) {
-        handle(nodes, i);
-        if (stopped) return;
-      }
-
-      if (flatten) {
+      if (context && context.didFlatten) {
         parent[key] = _.flatten(parent[key]);
 
         if (key === "body") {
@@ -122,8 +130,9 @@ function traverse(parent, opts, scope) {
         }
       }
     } else {
-      handle(parent, key);
-      if (stopped) return;
+      context = new TraversalContext(context);
+      context.visit(parent, key, opts, scope, parent);
+      if (context.didStop) return;
     }
   }
 }

lib/6to5/traverse/scope.js

@@ -24,7 +24,13 @@ function Scope(block, parent) {
 }
 
 var vars = require("jshint/src/vars");
-Scope.defaultDeclarations = _.flatten([vars.newEcmaIdentifiers, vars.node, vars.ecmaIdentifiers, vars.reservedVars].map(_.keys));
+
+Scope.defaultDeclarations = _.flatten([
+  vars.newEcmaIdentifiers,
+  vars.node,
+  vars.ecmaIdentifiers,
+  vars.reservedVars
+].map(_.keys));
 
 Scope.add = function (node, references) {
   if (!node) return;

lib/6to5/types/builder-keys.json

@@ -9,6 +9,7 @@
   "ExpressionStatement":     ["expression"],
   "File":                    ["program", "comments", "tokens"],
   "FunctionExpression":      ["id", "params", "body", "generator"],
+  "FunctionDeclaration":     ["id", "params", "body", "generator"],
   "Identifier":              ["name"],
   "IfStatement":             ["test", "consequent", "alternate"],
   "ImportDeclaration":       ["specifiers", "source"],
@@ -16,6 +17,7 @@
   "Literal":                 ["value"],
   "LogicalExpression":       ["operator", "left", "right"],
   "MemberExpression":        ["object", "property", "computed"],
+  "MethodDefinition":        ["key", "value", "computed", "kind"],
   "NewExpression":           ["callee", "arguments"],
   "ObjectExpression":        ["properties"],
   "Program":                 ["body"],

lib/6to5/types/index.js

@@ -307,6 +307,31 @@ t.toStatement = function (node, ignore) {
   return node;
 };
 
+/**
+ * Description
+ *
+ * @param {Object} node
+ * @returns {Object}
+ */
+
+exports.toExpression = function (node) {
+  if (t.isExpressionStatement(node)) {
+    node = node.expression;
+  }
+
+  if (t.isClass(node)) {
+    node.type = "ClassExpression";
+  } else if (t.isFunction(node)) {
+    node.type = "FunctionExpression";
+  }
+
+  if (t.isExpression(node)) {
+    return node;
+  } else {
+    throw new Error("cannot turn " + node.type + " to an expression");
+  }
+};
+
 /**
  * Description
  *
@@ -320,7 +345,11 @@ t.toBlock = function (node, parent) {
     return node;
   }
 
-  if (!_.isArray(node)) {
+  if (t.isEmptyStatement(node)) {
+    node = [];
+  }
+
+  if (!Array.isArray(node)) {
     if (!t.isStatement(node)) {
       if (t.isFunction(parent)) {
         node = t.returnStatement(node);
@@ -355,16 +384,24 @@ t.getIds = function (node, map, ignoreTypes) {
     if (!id) continue;
     if (_.contains(ignoreTypes, id.type)) continue;
 
-    var nodeKey = t.getIds.nodes[id.type];
+    var nodeKeys = t.getIds.nodes[id.type];
     var arrKeys  = t.getIds.arrays[id.type];
 
+    var i, key;
+
     if (t.isIdentifier(id)) {
       ids[id.name] = id;
-    } else if (nodeKey) {
-      if (id[nodeKey]) search.push(id[nodeKey]);
+    } else if (nodeKeys) {
+      for (i in nodeKeys) {
+        key = nodeKeys[i];
+        if (id[key]) {
+          search.push(id[key]);
+          break;
+        }
+      }
     } else if (arrKeys) {
-      for (var i in arrKeys) {
-        var key = arrKeys[i];
+      for (i in arrKeys) {
+        key = arrKeys[i];
         search = search.concat(id[key] || []);
       }
     }
@@ -375,15 +412,16 @@ t.getIds = function (node, map, ignoreTypes) {
 };
 
 t.getIds.nodes = {
-  AssignmentExpression: "left",
-  ImportSpecifier: "name",
-  ExportSpecifier: "name",
-  VariableDeclarator: "id",
-  FunctionDeclaration: "id",
-  ClassDeclaration: "id",
-  MemeberExpression: "object",
-  SpreadElement: "argument",
-  Property: "value"
+  AssignmentExpression: ["left"],
+  ImportBatchSpecifier: ["name"],
+  ImportSpecifier: ["name", "id"],
+  ExportSpecifier: ["name", "id"],
+  VariableDeclarator: ["id"],
+  FunctionDeclaration: ["id"],
+  ClassDeclaration: ["id"],
+  MemeberExpression: ["object"],
+  SpreadElement: ["argument"],
+  Property: ["value"]
 };
 
 t.getIds.arrays = {

lib/6to5/util.js

@@ -39,7 +39,7 @@ exports.list = function (val) {
 
 exports.regexify = function (val) {
   if (!val) return new RegExp(/.^/);
-  if (_.isArray(val)) val = val.join("|");
+  if (Array.isArray(val)) val = val.join("|");
   if (_.isString(val)) return new RegExp(val);
   if (_.isRegExp(val)) return val;
   throw new TypeError("illegal type for regexify");
@@ -48,7 +48,7 @@ exports.regexify = function (val) {
 exports.arrayify = function (val) {
   if (!val) return [];
   if (_.isString(val)) return exports.list(val);
-  if (_.isArray(val)) return val;
+  if (Array.isArray(val)) return val;
   throw new TypeError("illegal type for arrayify");
 };
 
@@ -65,12 +65,12 @@ exports.sourceMapToComment = function (map) {
   return "//# sourceMappingURL=data:application/json;base64," + base64;
 };
 
-exports.pushMutatorMap = function (mutatorMap, key, kind, method) {
+exports.pushMutatorMap = function (mutatorMap, key, kind, computed, method) {
   var alias;
 
   if (t.isIdentifier(key)) {
     alias = key.name;
-    if (method.computed) alias = "computed:" + alias;
+    if (computed) alias = "computed:" + alias;
   } else if (t.isLiteral(key)) {
     alias = String(key.value);
   } else {
@@ -86,7 +86,7 @@ exports.pushMutatorMap = function (mutatorMap, key, kind, method) {
   mutatorMap[alias] = map;
 
   map._key = key;
-  if (method.computed) {
+  if (computed) {
     map._computed = true;
   }
 
@@ -101,7 +101,12 @@ exports.buildDefineProperties = function (mutatorMap) {
 
     var propNode = t.property("init", map._key, mapNode, map._computed);
 
+    if (!map.get && !map.set) {
+      map.writable = t.literal(true);
+    }
+
     map.enumerable = t.literal(true);
+    map.configurable = t.literal(true);
 
     _.each(map, function (node, key) {
       if (key[0] === "_") return;
@@ -146,10 +151,10 @@ exports.template = function (name, nodes, keepExpression) {
   var node = template.body[0];
 
   if (!keepExpression && t.isExpressionStatement(node)) {
-    node = node.expression;
+    return node.expression;
+  } else {
+    return node;
   }
-
-  return node;
 };
 
 exports.codeFrame = function (lines, lineNumber, colNumber) {
@@ -188,7 +193,13 @@ exports.codeFrame = function (lines, lineNumber, colNumber) {
 
 exports.repeat = function (width, cha) {
   cha = cha || " ";
-  return new Array(width + 1).join(cha);
+
+  var result = "";
+  for (var i = 0; i < width; i++) {
+    result += cha;
+  }
+
+  return result;
 };
 
 exports.normaliseAst = function (ast, comments, tokens) {
@@ -256,7 +267,7 @@ var loadTemplates = function () {
   if (!fs.existsSync(templatesLoc)) {
     throw new Error("no templates directory - this is most likely the " +
                     "result of a broken `npm publish`. Please report to " +
-                    "https://githut.com/6to5/6to5/issues");
+                    "https://github.com/6to5/6to5/issues");
   }
 
   _.each(fs.readdirSync(templatesLoc), function (name) {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.6.0",
+  "version": "2.12.0",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -39,36 +39,36 @@
     "test": "make test"
   },
   "dependencies": {
-    "acorn-6to5": "0.11.1-11",
+    "acorn-6to5": "0.11.1-14",
     "ast-types": "~0.6.1",
     "chokidar": "0.11.1",
     "commander": "2.5.0",
-    "core-js": "^0.4.0",
+    "core-js": "0.4.4",
     "estraverse": "1.8.0",
     "esutils": "1.1.6",
-    "esvalid": "^1.1.0",
+    "esvalid": "1.1.0",
     "fs-readdir-recursive": "0.1.0",
-    "jshint": "^2.5.10",
+    "jshint": "2.5.10",
     "lodash": "2.4.1",
     "mkdirp": "0.5.0",
     "private": "0.1.6",
-    "regenerator": "^0.8.3",
+    "regenerator": "0.8.3",
     "regexpu": "0.3.0",
-    "roadrunner": "^1.0.4",
+    "roadrunner": "1.0.4",
     "source-map": "0.1.40",
     "source-map-support": "0.2.8"
   },
   "devDependencies": {
     "browserify": "6.3.2",
-    "chai": "^1.9.2",
+    "chai": "1.9.2",
     "istanbul": "0.3.2",
-    "jshint-stylish": "^1.0.0",
+    "jshint-stylish": "1.0.0",
     "matcha": "0.6.0",
     "mocha": "1.21.4",
     "rimraf": "2.2.8",
     "uglify-js": "2.4.15"
   },
   "optionalDependencies": {
-    "kexec": "^0.2.0"
+    "kexec": "0.2.0"
   }
 }

test/bin.js

@@ -1,5 +1,4 @@
-// skip these tests under instanbul since they're useless
-if (process.env.running_under_istanbul === '1') return;
+if (process.env.running_under_istanbul) return;
 
 var readdir = require("fs-readdir-recursive");
 var helper  = require("./_helper");

test/browserify.js

@@ -12,7 +12,7 @@ suite("browserify", function() {
       assert.ok(bundle.length, "bundle output code");
 
       // ensure that the code runs without throwing an exception
-      vm.runInNewContext(bundle, {});
+      vm.runInNewContext("var global = this;\n" + bundle, {});
       done();
     })
   })

test/esnext.js

@@ -1,5 +1,3 @@
-if (!process.env.ALL_6TO5_TESTS) return;
-
 require("./_transformation-helper")({
   name: "esnext"
 });

test/fixtures/esnext/es6-classes/getter-setter-super.js

@@ -1,9 +1,11 @@
-class Animal {
+class Base {
   get sound() {
     return 'I am a ' + this.type + '.';
   }
 }
 
+class Animal extends Base {}
+
 class Cat extends Animal {
   get type() { return 'cat'; }
 

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

@@ -7,4 +7,5 @@ var test = {
     * Inside bracket init
     */
   "b"]: "2"
-}, ok = 42;
+},
+    ok = 42;

test/fixtures/generation/comments/variable-declarator-line-comment/expected.js

@@ -3,6 +3,7 @@ function test() {
   // Leading to VariableDeclarator
   // Leading to VariableDeclarator
   i = 20,
+
   // Leading to VariableDeclarator
   // Leading to VariableDeclarator
   j = 20;

test/fixtures/generation/comments/variable-declarator-multi-comment/expected.js

@@ -5,6 +5,7 @@ function test() {
    * Leading to VariableDeclarator
    */
   i = 20,
+
   /*
    * Leading to VariableDeclarator
    * Leading to VariableDeclarator

test/fixtures/generation/harmony-edgecase/yield-precedence/expected.js

@@ -1,5 +1,6 @@
 function* foo() {
-  var a = yield wat(), b = 2;
+  var a = yield wat(),
+      b = 2;
   var c = yield a = b;
   yield a, yield b;
   yield a = b;

test/fixtures/generation/types/UpdateExpression/actual.js

@@ -1,2 +1,3 @@
 ++i;
 i++;
+(foo++).test();

test/fixtures/generation/types/UpdateExpression/expected.js

@@ -1,2 +1,3 @@
 ++i;
 i++;
+(foo++).test();

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

@@ -8,6 +8,9 @@ const foo = "foo";
 let foo, bar = "bar";
 var foo, bar = "bar";
 
-let foo = "foo", bar = "bar";
-var foo = "foo", bar = "bar";
-const foo = "foo", bar = "bar";
+let foo = "foo",
+    bar = "bar";
+var foo = "foo",
+    bar = "bar";
+const foo = "foo",
+      bar = "bar";

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

@@ -0,0 +1,25 @@
+class Test extends Foo {
+  constructor() {
+    woops.super.test();
+    super();
+    super.test();
+
+    super(...arguments);
+    super("test", ...arguments);
+
+    super.test(...arguments);
+    super.test("test", ...arguments);
+  }
+
+  test() {
+    super();
+    super(...arguments);
+    super("test", ...arguments);
+  }
+
+  static foo() {
+    super();
+    super(...arguments);
+    super("test", ...arguments);
+  }
+}