v1.12.23

Make AMD module id's optional

CHANGELOG.md

@@ -1,3 +1,13 @@
+# 1.12.23
+
+ * Fix generator function export hoisting.
+
+# 1.12.22
+
+ * Update `fs-readdir-recursive` and `chokidar`.
+ * Support array destructuring on iterables.
+ * Make amd module id optional. Thanks [@webpro](https://github.com/webpro).
+
 # 1.12.21
 
  * Fix unneccesary let scoping replacement.

bin/6to5/index.js

@@ -18,6 +18,7 @@ commander.option("-b, --blacklist [blacklist]", "Blacklist of transformers to NO
 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("-a, --amd-module-ids", "Insert module id in AMD modules", false);
 
 commander.on("--help", function(){
   var outKeys = function (title, obj) {
@@ -90,6 +91,7 @@ exports.opts = {
   whitelist:     commander.whitelist,
   sourceMap:     commander.sourceMaps || commander.sourceMapsInline,
   comments:      !commander.removeComments,
+  amdModuleIds:   commander.amdModuleIds,
   runtime:       commander.runtime,
   modules:       commander.modules
 };

doc/caveats.md

@@ -37,7 +37,7 @@ A polyfill is required for for-of functionality that implements `Symbol` and
 adds `prototype[Symbol.iterator]` behaviour to built-ins. Using the polyfills
 specified in [polyfill](polyfill.md) suffices.
 
-## Spread
+### Array destructuring / Spread
 
-An [ES6 polyfill](polyfill.md) is required in order for spread to work. More
-specifically a polyfill for `Array.from`.
+An [ES6 polyfill](polyfill.md) is required for spread and array destructuring.
+More specifically a polyfill for `Array.from`.

doc/features.md

@@ -133,13 +133,31 @@ for (var i of [1, 2, 3]) {
 ## 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 comprehension
 
 ```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
@@ -153,7 +171,17 @@ for (let i in arr) {
 ## 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

doc/modules.md

@@ -66,7 +66,7 @@ export function bar() {
 **Out**
 
 ```javascript
-define("filename", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   exports.bar = bar;
 
   var foo = _foo.default;
@@ -77,6 +77,12 @@ define("filename", ["exports", "foo"], function (exports, _foo) {
 });
 ```
 
+You can optionally specify to include the module id (using the `--amd-module-id` argument):
+
+```javascript
+define("filename", ["exports", "foo"], function (exports, _foo) {})
+```
+
 ### UMD
 
 **In**
@@ -94,7 +100,7 @@ export function bar() {
 ```javascript
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("filename", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }

doc/usage.md

@@ -115,12 +115,19 @@ to5.transformFile("filename.js", options, function (err, result) {
   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 module.
+  // By default, AMD modules are anonymous.
+  // Default: false
+  amdModuleIds: 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

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

@@ -78,7 +78,7 @@ exports.Literal = function (node) {
     val = JSON.stringify(val);
 
     // escape unicode characters
-    val = val.replace(/[\u007f-\uffff]/g, function(c) {
+    val = val.replace(/[\u007f-\uffff]/g, function (c) {
       return "\\u" + ("0000" + c.charCodeAt(0).toString(16)).slice(-4);
     });
 

lib/6to5/templates/array-from.js

@@ -0,0 +1 @@
+Array.from(VALUE);

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

@@ -29,10 +29,13 @@ AMDFormatter.prototype.transform = function (ast) {
   var params = _.values(this.ids);
   params.unshift(t.identifier("exports"));
 
-  var moduleName = this.getModuleName();
-
   var container = t.functionExpression(null, params, t.blockStatement(body));
-  var call = t.callExpression(t.identifier("define"), [t.literal(moduleName), names, container]);
+
+  var defineArgs = [names, container];
+  var moduleName = this.getModuleName();
+  if (moduleName) defineArgs.unshift(t.literal(moduleName));
+
+  var call = t.callExpression(t.identifier("define"), defineArgs);
 
   program.body = [t.expressionStatement(call)];
 };
@@ -42,6 +45,10 @@ AMDFormatter.prototype.getModuleName = function () {
   var filenameRelative = opts.filenameRelative;
   var moduleName = "";
 
+  if (!opts.amdModuleIds) {
+    return null;
+  }
+
   if (opts.moduleRoot) {
     moduleName = opts.moduleRoot + "/";
   }

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

@@ -22,8 +22,7 @@ CommonJSInteropFormatter.prototype.importSpecifier = function (specifier, node,
         })])
       )
     ]));
-    return;
+  } else {
+    CommonJSFormatter.prototype.importSpecifier.apply(this, arguments);
   }
-
-  CommonJSFormatter.prototype.importSpecifier.apply(this, arguments);
 };

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

@@ -5,9 +5,8 @@ var util         = require("../../util");
 var t            = require("../../types");
 var _            = require("lodash");
 
-function UMDFormatter(file) {
-  this.file = file;
-  this.ids  = {};
+function UMDFormatter() {
+  AMDFormatter.apply(this, arguments);
 }
 
 util.inherits(UMDFormatter, AMDFormatter);
@@ -32,10 +31,12 @@ UMDFormatter.prototype.transform = function (ast) {
 
   // runner
 
+  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: [t.literal(moduleName), t.arrayExpression([t.literal("exports")].concat(names))],
+    AMD_ARGUMENTS: defineArgs,
 
     COMMON_ARGUMENTS: names.map(function (name) {
       return t.callExpression(t.identifier("require"), [name]);

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

@@ -1,12 +1,12 @@
 var t = require("../../types");
-var _ = require("lodash");
 
 module.exports = function (ast, file) {
   var body = ast.program.body;
 
-  _.each(file.declarations, function (declar) {
+  for (var i in file.declarations) {
+    var declar = file.declarations[i];
     body.unshift(t.variableDeclaration("var", [
       t.variableDeclarator(declar.uid, declar.node)
     ]));
-  });
+  }
 };

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

@@ -1,5 +1,6 @@
-var t = require("../../types");
-var _ = require("lodash");
+var util = require("../../util");
+var t    = require("../../types");
+var _    = require("lodash");
 
 var buildVariableAssign = function (kind, id, init) {
   if (kind === false) {
@@ -11,50 +12,64 @@ var buildVariableAssign = function (kind, id, init) {
   }
 };
 
-var push = function (kind, nodes, elem, parentId) {
+var push = function (opts, nodes, elem, parentId) {
   if (t.isObjectPattern(elem)) {
-    pushObjectPattern(kind, nodes, elem, parentId);
+    pushObjectPattern(opts, nodes, elem, parentId);
   } else if (t.isArrayPattern(elem)) {
-    pushArrayPattern(kind, nodes, elem, parentId);
+    pushArrayPattern(opts, nodes, elem, parentId);
   } else if (t.isMemberExpression(elem)) {
     nodes.push(buildVariableAssign(false, elem, parentId));
   } else {
-    nodes.push(buildVariableAssign(kind, elem, parentId));
+    nodes.push(buildVariableAssign(opts.kind, elem, parentId));
   }
 };
 
-var pushObjectPattern = function (kind, nodes, pattern, parentId) {
+var pushObjectPattern = function (opts, nodes, pattern, parentId) {
   _.each(pattern.properties, function (prop) {
     var pattern2   = prop.value;
     var patternId2 = t.memberExpression(parentId, prop.key);
 
     if (t.isPattern(pattern2)) {
-      push(kind, nodes, pattern2, patternId2);
+      push(opts, nodes, pattern2, patternId2);
     } else {
-      nodes.push(buildVariableAssign(kind, pattern2, patternId2));
+      nodes.push(buildVariableAssign(opts.kind, pattern2, patternId2));
     }
   });
 };
 
-var pushArrayPattern = function (kind, nodes, pattern, parentId) {
+var pushArrayPattern = function (opts, nodes, pattern, parentId) {
+  var _parentId = t.identifier(opts.file.generateUid("ref", opts.scope));
+  nodes.push(t.variableDeclaration("var", [
+    t.variableDeclarator(_parentId, util.template("array-from", {
+      VALUE: parentId
+    }))
+  ]));
+  parentId = _parentId;
+
   _.each(pattern.elements, function (elem, i) {
     if (!elem) return;
 
     var newPatternId;
 
     if (t.isSpreadElement(elem)) {
-      newPatternId = t.callExpression(t.memberExpression(parentId, t.identifier("slice")), [t.literal(i)]);
+      newPatternId = util.template("array-from", {
+        VALUE: parentId
+      });
+
+      if (+i > 0) {
+        newPatternId = t.callExpression(t.memberExpression(newPatternId, t.identifier("slice")), [t.literal(i)]);
+      }
+
       elem = elem.argument;
     } else {
       newPatternId = t.memberExpression(parentId, t.literal(i), true);
     }
 
-    push(kind, nodes, elem, newPatternId);
+    push(opts, nodes, elem, newPatternId);
   });
 };
 
 var pushPattern = function (opts) {
-  var kind = opts.kind;
   var nodes = opts.nodes;
   var pattern = opts.pattern;
   var parentId = opts.id;
@@ -71,7 +86,7 @@ var pushPattern = function (opts) {
     parentId = key;
   }
 
-  push(kind, nodes, pattern, parentId);
+  push(opts, nodes, pattern, parentId);
 };
 
 exports.ForInStatement =
@@ -89,7 +104,11 @@ exports.ForOfStatement = function (node, parent, file, scope) {
 
   var nodes = [];
 
-  push(declar.kind, nodes, pattern, key);
+  push({
+    kind: declar.kind,
+    file: file,
+    scope: scope
+  }, nodes, pattern, key);
 
   t.ensureBlock(node);
 
@@ -141,7 +160,11 @@ exports.ExpressionStatement = function (node, parent, file, scope) {
     t.variableDeclarator(ref, expr.right)
   ]));
 
-  push(false, nodes, expr.left, ref);
+  push({
+    kind: false,
+    file: file,
+    scope: scope
+  }, nodes, expr.left, ref);
 
   return nodes;
 };

lib/6to5/transformation/transformers/generators/emit/explode-expressions.js

@@ -0,0 +1,204 @@
+/**
+ * Copyright (c) 2014, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * https://raw.github.com/facebook/regenerator/master/LICENSE file. An
+ * additional grant of patent rights can be found in the PATENTS file in
+ * the same directory.
+ */
+
+var assert = require("assert");
+var loc    = require("../util").loc;
+var t      = require("../../../../types");
+
+exports.ParenthesizedExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(this.explodeExpression(path.get("expression")));
+};
+
+exports.MemberExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.memberExpression(
+    this.explodeExpression(path.get("object")),
+    expr.computed ? explodeViaTempVar(null, path.get("property")) : expr.property,
+    expr.computed
+  ));
+};
+
+exports.CallExpression = function (expr, path, explodeViaTempVar, finish) {
+  var oldCalleePath = path.get("callee");
+  var newCallee = this.explodeExpression(oldCalleePath);
+
+  // If the callee was not previously a MemberExpression, then the
+  // CallExpression was "unqualified," meaning its `this` object should
+  // be the global object. If the exploded expression has become a
+  // MemberExpression, then we need to force it to be unqualified by
+  // using the (0, object.property)(...) trick; otherwise, it will
+  // receive the object of the MemberExpression as its `this` object.
+  if (!t.isMemberExpression(oldCalleePath.node) && t.isMemberExpression(newCallee)) {
+    newCallee = t.sequenceExpression([
+      t.literal(0),
+      newCallee
+    ]);
+  }
+
+  return finish(t.callExpression(
+    newCallee,
+    path.get("arguments").map(function (argPath) {
+      return explodeViaTempVar(null, argPath);
+    })
+  ));
+};
+
+exports.NewExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.newExpression(
+    explodeViaTempVar(null, path.get("callee")),
+    path.get("arguments").map(function (argPath) {
+      return explodeViaTempVar(null, argPath);
+    })
+  ));
+};
+
+exports.ObjectExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.objectExpression(
+    path.get("properties").map(function (propPath) {
+      return t.property(
+        propPath.value.kind,
+        propPath.value.key,
+        explodeViaTempVar(null, propPath.get("value"))
+      );
+    })
+  ));
+};
+
+exports.ArrayExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.arrayExpression(
+    path.get("elements").map(function (elemPath) {
+      return explodeViaTempVar(null, elemPath);
+    })
+  ));
+};
+
+exports.SequenceExpression = function (expr, path, explodeViaTempVar, finish, ignoreResult) {
+  var lastIndex = expr.expressions.length - 1;
+  var self = this;
+  var result;
+
+  path.get("expressions").each(function (exprPath) {
+    if (exprPath.name === lastIndex) {
+      result = self.explodeExpression(exprPath, ignoreResult);
+    } else {
+      self.explodeExpression(exprPath, true);
+    }
+  });
+
+  return result;
+};
+
+exports.LogicalExpression = function (expr, path, explodeViaTempVar, finish, ignoreResult) {
+  var after = loc();
+  var result;
+
+  if (!ignoreResult) {
+    result = this.makeTempVar();
+  }
+
+  var left = explodeViaTempVar(result, path.get("left"));
+
+  if (expr.operator === "&&") {
+    this.jumpIfNot(left, after);
+  } else {
+    assert.strictEqual(expr.operator, "||");
+    this.jumpIf(left, after);
+  }
+
+  explodeViaTempVar(result, path.get("right"), ignoreResult);
+
+  this.mark(after);
+
+  return result;
+};
+
+exports.ConditionalExpression = function (expr, path, explodeViaTempVar, finish, ignoreResult) {
+  var elseLoc = loc();
+  var after = loc();
+  var test = this.explodeExpression(path.get("test"));
+  var result;
+
+  this.jumpIfNot(test, elseLoc);
+
+  if (!ignoreResult) {
+    result = this.makeTempVar();
+  }
+
+  explodeViaTempVar(result, path.get("consequent"), ignoreResult);
+  this.jump(after);
+
+  this.mark(elseLoc);
+  explodeViaTempVar(result, path.get("alternate"), ignoreResult);
+
+  this.mark(after);
+
+  return result;
+};
+
+exports.UnaryExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.unaryExpression(
+    expr.operator,
+    // Can't (and don't need to) break up the syntax of the argument.
+    // Think about delete a[b].
+    this.explodeExpression(path.get("argument")),
+    !!expr.prefix
+  ));
+};
+
+exports.BinaryExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.binaryExpression(
+    expr.operator,
+    explodeViaTempVar(null, path.get("left")),
+    explodeViaTempVar(null, path.get("right"))
+  ));
+};
+
+exports.AssignmentExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.assignmentExpression(
+    expr.operator,
+    this.explodeExpression(path.get("left")),
+    this.explodeExpression(path.get("right"))
+  ));
+};
+
+exports.UpdateExpression = function (expr, path, explodeViaTempVar, finish) {
+  return finish(t.updateExpression(
+    expr.operator,
+    this.explodeExpression(path.get("argument")),
+    expr.prefix
+  ));
+};
+
+exports.YieldExpression = function (expr, path) {
+  var after = loc();
+  var arg = expr.argument && this.explodeExpression(path.get("argument"));
+  var result;
+
+  if (arg && expr.delegate) {
+    result = this.makeTempVar();
+
+    this.emit(t.returnStatement(t.callExpression(
+      this.contextProperty("delegateYield"), [
+        arg,
+        t.literal(result.property.name),
+        after
+      ]
+    )));
+
+    this.mark(after);
+
+    return result;
+  }
+
+  this.emitAssign(this.contextProperty("next"), after);
+  this.emit(t.returnStatement(arg || null));
+  this.mark(after);
+
+  return this.contextProperty("sent");
+};

lib/6to5/transformation/transformers/generators/emit/explode-statements.js

@@ -0,0 +1,334 @@
+/**
+ * Copyright (c) 2014, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * https://raw.github.com/facebook/regenerator/master/LICENSE file. An
+ * additional grant of patent rights can be found in the PATENTS file in
+ * the same directory.
+ */
+
+var assert = require("assert");
+var types  = require("ast-types");
+var leap   = require("../leap");
+var util   = require("../util");
+var t      = require("../../../../types");
+
+var runtimeKeysMethod = util.runtimeProperty("keys");
+var loc               = util.loc;
+
+exports.ExpressionStatement = function (path) {
+  this.explodeExpression(path.get("expression"), true);
+};
+
+exports.LabeledStatement = function (path, stmt) {
+  this.explodeStatement(path.get("body"), stmt.label);
+};
+
+exports.WhileStatement = function (path, stmt, labelId) {
+  var before = loc();
+  var after = loc();
+
+  this.mark(before);
+  this.jumpIfNot(this.explodeExpression(path.get("test")), after);
+  this.leapManager.withEntry(
+    new leap.LoopEntry(after, before, labelId),
+    function () { this.explodeStatement(path.get("body")); }
+  );
+  this.jump(before);
+  this.mark(after);
+};
+
+exports.DoWhileStatement = function (path, stmt, labelId) {
+  var first = loc();
+  var test = loc();
+  var after = loc();
+
+  this.mark(first);
+  this.leapManager.withEntry(
+    new leap.LoopEntry(after, test, labelId),
+    function () { this.explode(path.get("body")); }
+  );
+  this.mark(test);
+  this.jumpIf(this.explodeExpression(path.get("test")), first);
+  this.mark(after);
+};
+
+exports.ForStatement = function (path, stmt, labelId) {
+  var head = loc();
+  var update = loc();
+  var after = loc();
+
+  if (stmt.init) {
+    // We pass true here to indicate that if stmt.init is an expression
+    // then we do not care about its result.
+    this.explode(path.get("init"), true);
+  }
+
+  this.mark(head);
+
+  if (stmt.test) {
+    this.jumpIfNot(this.explodeExpression(path.get("test")), after);
+  } else {
+    // No test means continue unconditionally.
+  }
+
+  this.leapManager.withEntry(
+    new leap.LoopEntry(after, update, labelId),
+    function () { this.explodeStatement(path.get("body")); }
+  );
+
+  this.mark(update);
+
+  if (stmt.update) {
+    // We pass true here to indicate that if stmt.update is an
+    // expression then we do not care about its result.
+    this.explode(path.get("update"), true);
+  }
+
+  this.jump(head);
+
+  this.mark(after);
+};
+
+exports.ForInStatement = function (path, stmt, labelId) {
+  t.assertIdentifier(stmt.left);
+
+  var head = loc();
+  var after = loc();
+
+  var keyIterNextFn = this.makeTempVar();
+  this.emitAssign(
+    keyIterNextFn,
+    t.callExpression(
+      runtimeKeysMethod,
+      [this.explodeExpression(path.get("right"))]
+    )
+  );
+
+  this.mark(head);
+
+  var keyInfoTmpVar = this.makeTempVar();
+  this.jumpIf(
+    t.memberExpression(
+      t.assignmentExpression(
+        "=",
+        keyInfoTmpVar,
+        t.callExpression(keyIterNextFn, [])
+      ),
+      t.identifier("done"),
+      false
+    ),
+    after
+  );
+
+  this.emitAssign(
+    stmt.left,
+    t.memberExpression(
+      keyInfoTmpVar,
+      t.identifier("value"),
+      false
+    )
+  );
+
+  this.leapManager.withEntry(
+    new leap.LoopEntry(after, head, labelId),
+    function () { this.explodeStatement(path.get("body")); }
+  );
+
+  this.jump(head);
+
+  this.mark(after);
+};
+
+exports.BreakStatement = function (path, stmt) {
+  this.emitAbruptCompletion({
+    type: "break",
+    target: this.leapManager.getBreakLoc(stmt.label)
+  });
+};
+
+exports.ContinueStatement = function (path, stmt) {
+  this.emitAbruptCompletion({
+    type: "continue",
+    target: this.leapManager.getContinueLoc(stmt.label)
+  });
+};
+
+exports.SwitchStatement = function (path, stmt) {
+  // Always save the discriminant into a temporary variable in case the
+  // test expressions overwrite values like context.sent.
+  var disc = this.emitAssign(
+    this.makeTempVar(),
+    this.explodeExpression(path.get("discriminant"))
+  );
+
+  var after = loc();
+  var defaultLoc = loc();
+  var condition = defaultLoc;
+  var caseLocs = [];
+  var self = this;
+
+  // If there are no cases, .cases might be undefined.
+  var cases = stmt.cases || [];
+
+  for (var i = cases.length - 1; i >= 0; --i) {
+    var c = cases[i];
+    t.assertSwitchCase(c);
+
+    if (c.test) {
+      condition = t.conditionalExpression(
+        t.binaryExpression("===", disc, c.test),
+        caseLocs[i] = loc(),
+        condition
+      );
+    } else {
+      caseLocs[i] = defaultLoc;
+    }
+  }
+
+  this.jump(this.explodeExpression(
+    new types.NodePath(condition, path, "discriminant")
+  ));
+
+  this.leapManager.withEntry(
+    new leap.SwitchEntry(after),
+    function () {
+      path.get("cases").each(function (casePath) {
+        var i = casePath.name;
+
+        self.mark(caseLocs[i]);
+
+        casePath.get("consequent").each(
+          self.explodeStatement,
+          self
+        );
+      });
+    }
+  );
+
+  this.mark(after);
+  if (defaultLoc.value === -1) {
+    this.mark(defaultLoc);
+    assert.strictEqual(after.value, defaultLoc.value);
+  }
+};
+
+exports.IfStatement = function (path, stmt) {
+  var elseLoc = stmt.alternate && loc();
+  var after = loc();
+
+  this.jumpIfNot(
+    this.explodeExpression(path.get("test")),
+    elseLoc || after
+  );
+
+  this.explodeStatement(path.get("consequent"));
+
+  if (elseLoc) {
+    this.jump(after);
+    this.mark(elseLoc);
+    this.explodeStatement(path.get("alternate"));
+  }
+
+  this.mark(after);
+};
+
+exports.ReturnStatement = function (path) {
+  this.emitAbruptCompletion({
+    type: "return",
+    value: this.explodeExpression(path.get("argument"))
+  });
+};
+
+exports.TryStatement = function (path, stmt) {
+  var after = loc();
+  var self = this;
+
+  var handler = stmt.handler;
+  if (!handler && stmt.handlers) {
+    handler = stmt.handlers[0] || null;
+  }
+
+  var catchLoc = handler && loc();
+  var catchEntry = catchLoc && new leap.CatchEntry(
+    catchLoc,
+    handler.param
+  );
+
+  var finallyLoc = stmt.finalizer && loc();
+  var finallyEntry = finallyLoc && new leap.FinallyEntry(finallyLoc);
+
+  var tryEntry = new leap.TryEntry(
+    this.getUnmarkedCurrentLoc(),
+    catchEntry,
+    finallyEntry
+  );
+
+  this.tryEntries.push(tryEntry);
+  this.updateContextPrevLoc(tryEntry.firstLoc);
+
+  this.leapManager.withEntry(tryEntry, function () {
+    this.explodeStatement(path.get("block"));
+
+    if (catchLoc) {
+      if (finallyLoc) {
+        // If we have both a catch block and a finally block, then
+        // because we emit the catch block first, we need to jump over
+        // it to the finally block.
+        this.jump(finallyLoc);
+
+      } else {
+        // If there is no finally block, then we need to jump over the
+        // catch block to the fall-through location.
+        this.jump(after);
+      }
+
+      this.updateContextPrevLoc(self.mark(catchLoc));
+
+      var bodyPath = path.get("handler", "body");
+      var safeParam = this.makeTempVar();
+      this.clearPendingException(tryEntry.firstLoc, safeParam);
+
+      var catchScope = bodyPath.scope;
+      var catchParamName = handler.param.name;
+      t.assertCatchClause(catchScope.node);
+      assert.strictEqual(catchScope.lookup(catchParamName), catchScope);
+
+      types.visit(bodyPath, {
+        visitIdentifier: function (path) {
+          if (path.value.name === catchParamName &&
+              path.scope.lookup(catchParamName) === catchScope) {
+            return safeParam;
+          }
+          this.traverse(path);
+        }
+      });
+
+      this.leapManager.withEntry(catchEntry, function () {
+        this.explodeStatement(bodyPath);
+      });
+    }
+
+    if (finallyLoc) {
+      this.updateContextPrevLoc(this.mark(finallyLoc));
+
+      this.leapManager.withEntry(finallyEntry, function () {
+        this.explodeStatement(path.get("finalizer"));
+      });
+
+      this.emit(t.callExpression(
+        this.contextProperty("finish"),
+        [finallyEntry.firstLoc]
+      ));
+    }
+  });
+
+  this.mark(after);
+};
+
+exports.ThrowStatement = function (path) {
+  this.emit(t.throwStatement(
+    this.explodeExpression(path.get("argument"))
+  ));
+};

lib/6to5/transformation/transformers/generators/emit/index.js

@@ -10,16 +10,18 @@
 
 exports.Emitter = Emitter;
 
-var runtimeProperty = require("./util").runtimeProperty;
-var assert          = require("assert");
-var types           = require("ast-types");
-var leap            = require("./leap");
-var meta            = require("./meta");
-var t               = require("../../../types");
-var _               = require("lodash");
+var explodeExpressions = require("./explode-expressions");
+var explodeStatements  = require("./explode-statements");
+var assert             = require("assert");
+var types              = require("ast-types");
+var leap               = require("../leap");
+var meta               = require("../meta");
+var util               = require("../util");
+var t                  = require("../../../../types");
+var _                  = require("lodash");
 
-var runtimeKeysMethod = runtimeProperty("keys");
-var n                 = types.namedTypes;
+var loc = util.loc;
+var n   = types.namedTypes;
 
 function Emitter(contextId) {
   assert.ok(this instanceof Emitter);
@@ -52,18 +54,9 @@ function Emitter(contextId) {
   this.leapManager = new leap.LeapManager(this);
 }
 
-// Offsets into this.listing that could be used as targets for branches or
-// jumps are represented as numeric Literal nodes. This representation has
-// the amazingly convenient benefit of allowing the exact value of the
-// location to be determined at any time, even after generating code that
-// refers to the location.
-function loc() {
-  return t.literal(-1);
-}
-
 // Sets the exact value of the given location to the offset of the next
 // Statement emitted.
-Emitter.prototype.mark = function(loc) {
+Emitter.prototype.mark = function (loc) {
   t.assertLiteral(loc);
   var index = this.listing.length;
   if (loc.value === -1) {
@@ -77,7 +70,7 @@ Emitter.prototype.mark = function(loc) {
   return loc;
 };
 
-Emitter.prototype.emit = function(node) {
+Emitter.prototype.emit = function (node) {
   if (t.isExpression(node)) node = t.expressionStatement(node);
   t.assertStatement(node);
   this.listing.push(node);
@@ -85,20 +78,20 @@ Emitter.prototype.emit = function(node) {
 
 // Shorthand for emitting assignment statements. This will come in handy
 // for assignments to temporary variables.
-Emitter.prototype.emitAssign = function(lhs, rhs) {
+Emitter.prototype.emitAssign = function (lhs, rhs) {
   this.emit(this.assign(lhs, rhs));
   return lhs;
 };
 
 // Shorthand for an assignment statement.
-Emitter.prototype.assign = function(lhs, rhs) {
+Emitter.prototype.assign = function (lhs, rhs) {
   return t.expressionStatement(
     t.assignmentExpression("=", lhs, rhs));
 };
 
 // Convenience function for generating expressions like context.next,
 // context.sent, and context.rval.
-Emitter.prototype.contextProperty = function(name, computed) {
+Emitter.prototype.contextProperty = function (name, computed) {
   return t.memberExpression(
     this.contextId,
     computed ? t.literal(name) : t.identifier(name),
@@ -116,7 +109,7 @@ var volatileContextPropertyNames = {
 // A "volatile" context property is a MemberExpression like context.sent
 // that should probably be stored in a temporary variable when there's a
 // possibility the property will get overwritten.
-Emitter.prototype.isVolatileContextProperty = function(expr) {
+Emitter.prototype.isVolatileContextProperty = function (expr) {
   if (t.isMemberExpression(expr)) {
     if (expr.computed) {
       // If it's a computed property such as context[couldBeAnything],
@@ -136,7 +129,7 @@ Emitter.prototype.isVolatileContextProperty = function(expr) {
 };
 
 // Shorthand for setting context.rval and jumping to `context.stop()`.
-Emitter.prototype.stop = function(rval) {
+Emitter.prototype.stop = function (rval) {
   if (rval) {
     this.setReturnValue(rval);
   }
@@ -144,7 +137,7 @@ Emitter.prototype.stop = function(rval) {
   this.jump(this.finalLoc);
 };
 
-Emitter.prototype.setReturnValue = function(valuePath) {
+Emitter.prototype.setReturnValue = function (valuePath) {
   t.assertExpression(valuePath.value);
 
   this.emitAssign(
@@ -153,7 +146,7 @@ Emitter.prototype.setReturnValue = function(valuePath) {
   );
 };
 
-Emitter.prototype.clearPendingException = function(tryLoc, assignee) {
+Emitter.prototype.clearPendingException = function (tryLoc, assignee) {
   t.assertLiteral(tryLoc);
 
   var catchCall = t.callExpression(
@@ -170,13 +163,13 @@ Emitter.prototype.clearPendingException = function(tryLoc, assignee) {
 
 // Emits code for an unconditional jump to the given location, even if the
 // exact value of the location is not yet known.
-Emitter.prototype.jump = function(toLoc) {
+Emitter.prototype.jump = function (toLoc) {
   this.emitAssign(this.contextProperty("next"), toLoc);
   this.emit(t.breakStatement());
 };
 
 // Conditional jump.
-Emitter.prototype.jumpIf = function(test, toLoc) {
+Emitter.prototype.jumpIf = function (test, toLoc) {
   t.assertExpression(test);
   t.assertLiteral(toLoc);
 
@@ -190,7 +183,7 @@ Emitter.prototype.jumpIf = function(test, toLoc) {
 };
 
 // Conditional jump, with the condition negated.
-Emitter.prototype.jumpIfNot = function(test, toLoc) {
+Emitter.prototype.jumpIfNot = function (test, toLoc) {
   t.assertExpression(test);
   t.assertLiteral(toLoc);
 
@@ -217,11 +210,11 @@ Emitter.prototype.jumpIfNot = function(test, toLoc) {
 // other local variables, and since we just increment `nextTempId`
 // monotonically, uniqueness is assured.
 var nextTempId = 0;
-Emitter.prototype.makeTempVar = function() {
+Emitter.prototype.makeTempVar = function () {
   return this.contextProperty("t" + nextTempId++);
 };
 
-Emitter.prototype.getContextFunction = function(id) {
+Emitter.prototype.getContextFunction = function (id) {
   var node = t.functionExpression(
     id || null,
     [this.contextId],
@@ -244,7 +237,7 @@ Emitter.prototype.getContextFunction = function(id) {
 //
 // Each marked location in this.listing will correspond to one generated
 // case statement.
-Emitter.prototype.getDispatchLoop = function() {
+Emitter.prototype.getDispatchLoop = function () {
   var self = this;
   var cases = [];
   var current;
@@ -253,7 +246,7 @@ Emitter.prototype.getDispatchLoop = function() {
   // case, we can skip the rest of the statements until the next case.
   var alreadyEnded = false;
 
-  self.listing.forEach(function(stmt, i) {
+  self.listing.forEach(function (stmt, i) {
     if (self.marked.hasOwnProperty(i)) {
       cases.push(t.switchCase(t.literal(i), current = []));
       alreadyEnded = false;
@@ -306,7 +299,7 @@ function isSwitchCaseEnder(stmt) {
          t.isThrowStatement(stmt);
 }
 
-Emitter.prototype.getTryEntryList = function() {
+Emitter.prototype.getTryEntryList = function () {
   if (this.tryEntries.length === 0) {
     // To avoid adding a needless [] to the majority of runtime.wrap
     // argument lists, force the caller to handle this case specially.
@@ -316,7 +309,7 @@ Emitter.prototype.getTryEntryList = function() {
   var lastLocValue = 0;
 
   return t.arrayExpression(
-    this.tryEntries.map(function(tryEntry) {
+    this.tryEntries.map(function (tryEntry) {
       var thisLocValue = tryEntry.firstLoc.value;
       assert.ok(thisLocValue >= lastLocValue, "try entries out of order");
       lastLocValue = thisLocValue;
@@ -346,7 +339,7 @@ Emitter.prototype.getTryEntryList = function() {
 
 // No destructive modification of AST nodes.
 
-Emitter.prototype.explode = function(path, ignoreResult) {
+Emitter.prototype.explode = function (path, ignoreResult) {
   assert.ok(path instanceof types.NodePath);
 
   var node = path.value;
@@ -389,12 +382,11 @@ function getDeclError(node) {
     JSON.stringify(node));
 }
 
-Emitter.prototype.explodeStatement = function(path, labelId) {
+Emitter.prototype.explodeStatement = function (path, labelId) {
   assert.ok(path instanceof types.NodePath);
 
   var stmt = path.value;
   var self = this;
-  var after, head;
 
   t.assertStatement(stmt);
 
@@ -423,338 +415,15 @@ Emitter.prototype.explodeStatement = function(path, labelId) {
     return;
   }
 
-  switch (stmt.type) {
-  case "ExpressionStatement":
-    self.explodeExpression(path.get("expression"), true);
-    break;
-
-  case "LabeledStatement":
-    self.explodeStatement(path.get("body"), stmt.label);
-    break;
-
-  case "WhileStatement":
-    var before = loc();
-    after = loc();
-
-    self.mark(before);
-    self.jumpIfNot(self.explodeExpression(path.get("test")), after);
-    self.leapManager.withEntry(
-      new leap.LoopEntry(after, before, labelId),
-      function() { self.explodeStatement(path.get("body")); }
-    );
-    self.jump(before);
-    self.mark(after);
-
-    break;
-
-  case "DoWhileStatement":
-    var first = loc();
-    var test = loc();
-    after = loc();
-
-    self.mark(first);
-    self.leapManager.withEntry(
-      new leap.LoopEntry(after, test, labelId),
-      function() { self.explode(path.get("body")); }
-    );
-    self.mark(test);
-    self.jumpIf(self.explodeExpression(path.get("test")), first);
-    self.mark(after);
-
-    break;
-
-  case "ForStatement":
-    head = loc();
-    var update = loc();
-    after = loc();
-
-    if (stmt.init) {
-      // We pass true here to indicate that if stmt.init is an expression
-      // then we do not care about its result.
-      self.explode(path.get("init"), true);
-    }
-
-    self.mark(head);
-
-    if (stmt.test) {
-      self.jumpIfNot(self.explodeExpression(path.get("test")), after);
-    } else {
-      // No test means continue unconditionally.
-    }
-
-    self.leapManager.withEntry(
-      new leap.LoopEntry(after, update, labelId),
-      function() { self.explodeStatement(path.get("body")); }
-    );
-
-    self.mark(update);
-
-    if (stmt.update) {
-      // We pass true here to indicate that if stmt.update is an
-      // expression then we do not care about its result.
-      self.explode(path.get("update"), true);
-    }
-
-    self.jump(head);
-
-    self.mark(after);
-
-    break;
-
-  case "ForInStatement":
-    t.assertIdentifier(stmt.left);
-
-    head = loc();
-    after = loc();
-
-    var keyIterNextFn = self.makeTempVar();
-    self.emitAssign(
-      keyIterNextFn,
-      t.callExpression(
-        runtimeKeysMethod,
-        [self.explodeExpression(path.get("right"))]
-      )
-    );
-
-    self.mark(head);
-
-    var keyInfoTmpVar = self.makeTempVar();
-    self.jumpIf(
-      t.memberExpression(
-        t.assignmentExpression(
-          "=",
-          keyInfoTmpVar,
-          t.callExpression(keyIterNextFn, [])
-        ),
-        t.identifier("done"),
-        false
-      ),
-      after
-    );
-
-    self.emitAssign(
-      stmt.left,
-      t.memberExpression(
-        keyInfoTmpVar,
-        t.identifier("value"),
-        false
-      )
-    );
-
-    self.leapManager.withEntry(
-      new leap.LoopEntry(after, head, labelId),
-      function() { self.explodeStatement(path.get("body")); }
-    );
-
-    self.jump(head);
-
-    self.mark(after);
-
-    break;
-
-  case "BreakStatement":
-    self.emitAbruptCompletion({
-      type: "break",
-      target: self.leapManager.getBreakLoc(stmt.label)
-    });
-
-    break;
-
-  case "ContinueStatement":
-    self.emitAbruptCompletion({
-      type: "continue",
-      target: self.leapManager.getContinueLoc(stmt.label)
-    });
-
-    break;
-
-  case "SwitchStatement":
-    // Always save the discriminant into a temporary variable in case the
-    // test expressions overwrite values like context.sent.
-    var disc = self.emitAssign(
-      self.makeTempVar(),
-      self.explodeExpression(path.get("discriminant"))
-    );
-
-    after = loc();
-    var defaultLoc = loc();
-    var condition = defaultLoc;
-    var caseLocs = [];
-
-    // If there are no cases, .cases might be undefined.
-    var cases = stmt.cases || [];
-
-    for (var i = cases.length - 1; i >= 0; --i) {
-      var c = cases[i];
-      t.assertSwitchCase(c);
-
-      if (c.test) {
-        condition = t.conditionalExpression(
-          t.binaryExpression("===", disc, c.test),
-          caseLocs[i] = loc(),
-          condition
-        );
-      } else {
-        caseLocs[i] = defaultLoc;
-      }
-    }
-
-    self.jump(self.explodeExpression(
-      new types.NodePath(condition, path, "discriminant")
-    ));
-
-    self.leapManager.withEntry(
-      new leap.SwitchEntry(after),
-      function() {
-        path.get("cases").each(function(casePath) {
-          var i = casePath.name;
-
-          self.mark(caseLocs[i]);
-
-          casePath.get("consequent").each(
-            self.explodeStatement,
-            self
-          );
-        });
-      }
-    );
-
-    self.mark(after);
-    if (defaultLoc.value === -1) {
-      self.mark(defaultLoc);
-      assert.strictEqual(after.value, defaultLoc.value);
-    }
-
-    break;
-
-  case "IfStatement":
-    var elseLoc = stmt.alternate && loc();
-    after = loc();
-
-    self.jumpIfNot(
-      self.explodeExpression(path.get("test")),
-      elseLoc || after
-    );
-
-    self.explodeStatement(path.get("consequent"));
-
-    if (elseLoc) {
-      self.jump(after);
-      self.mark(elseLoc);
-      self.explodeStatement(path.get("alternate"));
-    }
-
-    self.mark(after);
-
-    break;
-
-  case "ReturnStatement":
-    self.emitAbruptCompletion({
-      type: "return",
-      value: self.explodeExpression(path.get("argument"))
-    });
-
-    break;
-
-  case "TryStatement":
-    after = loc();
-
-    var handler = stmt.handler;
-    if (!handler && stmt.handlers) {
-      handler = stmt.handlers[0] || null;
-    }
-
-    var catchLoc = handler && loc();
-    var catchEntry = catchLoc && new leap.CatchEntry(
-      catchLoc,
-      handler.param
-    );
-
-    var finallyLoc = stmt.finalizer && loc();
-    var finallyEntry = finallyLoc && new leap.FinallyEntry(finallyLoc);
-
-    var tryEntry = new leap.TryEntry(
-      self.getUnmarkedCurrentLoc(),
-      catchEntry,
-      finallyEntry
-    );
-
-    self.tryEntries.push(tryEntry);
-    self.updateContextPrevLoc(tryEntry.firstLoc);
-
-    self.leapManager.withEntry(tryEntry, function() {
-      self.explodeStatement(path.get("block"));
-
-      if (catchLoc) {
-        if (finallyLoc) {
-          // If we have both a catch block and a finally block, then
-          // because we emit the catch block first, we need to jump over
-          // it to the finally block.
-          self.jump(finallyLoc);
-
-        } else {
-          // If there is no finally block, then we need to jump over the
-          // catch block to the fall-through location.
-          self.jump(after);
-        }
-
-        self.updateContextPrevLoc(self.mark(catchLoc));
-
-        var bodyPath = path.get("handler", "body");
-        var safeParam = self.makeTempVar();
-        self.clearPendingException(tryEntry.firstLoc, safeParam);
-
-        var catchScope = bodyPath.scope;
-        var catchParamName = handler.param.name;
-        t.assertCatchClause(catchScope.node);
-        assert.strictEqual(catchScope.lookup(catchParamName), catchScope);
-
-        types.visit(bodyPath, {
-          visitIdentifier: function(path) {
-            if (path.value.name === catchParamName &&
-                path.scope.lookup(catchParamName) === catchScope) {
-              return safeParam;
-            }
-            this.traverse(path);
-          }
-        });
-
-        self.leapManager.withEntry(catchEntry, function() {
-          self.explodeStatement(bodyPath);
-        });
-      }
-
-      if (finallyLoc) {
-        self.updateContextPrevLoc(self.mark(finallyLoc));
-
-        self.leapManager.withEntry(finallyEntry, function() {
-          self.explodeStatement(path.get("finalizer"));
-        });
-
-        self.emit(t.callExpression(
-          self.contextProperty("finish"),
-          [finallyEntry.firstLoc]
-        ));
-      }
-    });
-
-    self.mark(after);
-
-    break;
-
-  case "ThrowStatement":
-    self.emit(t.throwStatement(
-      self.explodeExpression(path.get("argument"))
-    ));
-
-    break;
-
-  default:
+  var fn = explodeStatements[stmt.type];
+  if (fn) {
+    fn.call(this, path, stmt, labelId);
+  } else {
     throw new Error("unknown Statement of type " + JSON.stringify(stmt.type));
   }
 };
 
-Emitter.prototype.emitAbruptCompletion = function(record) {
+Emitter.prototype.emitAbruptCompletion = function (record) {
   if (!isValidCompletion(record)) {
     assert.ok(
       false,
@@ -816,7 +485,7 @@ function isValidCompletion(record) {
 // statements). There's no logical harm in marking such locations as jump
 // targets, but minimizing the number of switch cases keeps the generated
 // code shorter.
-Emitter.prototype.getUnmarkedCurrentLoc = function() {
+Emitter.prototype.getUnmarkedCurrentLoc = function () {
   return t.literal(this.listing.length);
 };
 
@@ -830,7 +499,7 @@ Emitter.prototype.getUnmarkedCurrentLoc = function() {
 // would know the location of the current instruction with complete
 // precision at all times, but we don't have that luxury here, as it would
 // be costly and verbose to set context.prev before every statement.
-Emitter.prototype.updateContextPrevLoc = function(loc) {
+Emitter.prototype.updateContextPrevLoc = function (loc) {
   if (loc) {
     t.assertLiteral(loc);
 
@@ -853,7 +522,7 @@ Emitter.prototype.updateContextPrevLoc = function(loc) {
   this.emitAssign(this.contextProperty("prev"), loc);
 };
 
-Emitter.prototype.explodeExpression = function(path, ignoreResult) {
+Emitter.prototype.explodeExpression = function (path, ignoreResult) {
   assert.ok(path instanceof types.NodePath);
 
   var expr = path.value;
@@ -864,7 +533,6 @@ Emitter.prototype.explodeExpression = function(path, ignoreResult) {
   }
 
   var self = this;
-  var result, after; // Used optionally by several cases below.
 
   function finish(expr) {
     t.assertExpression(expr);
@@ -934,180 +602,10 @@ Emitter.prototype.explodeExpression = function(path, ignoreResult) {
   // emitting the expression with all its side effects, and we should not
   // return a result.
 
-  switch (expr.type) {
-  case "ParenthesizedExpression":
-    return finish(self.explodeExpression(path.get("expression")));
-
-  case "MemberExpression":
-    return finish(t.memberExpression(
-      self.explodeExpression(path.get("object")),
-      expr.computed ? explodeViaTempVar(null, path.get("property")) : expr.property,
-      expr.computed
-    ));
-
-  case "CallExpression":
-    var oldCalleePath = path.get("callee");
-    var newCallee = self.explodeExpression(oldCalleePath);
-
-    // If the callee was not previously a MemberExpression, then the
-    // CallExpression was "unqualified," meaning its `this` object should
-    // be the global object. If the exploded expression has become a
-    // MemberExpression, then we need to force it to be unqualified by
-    // using the (0, object.property)(...) trick; otherwise, it will
-    // receive the object of the MemberExpression as its `this` object.
-    if (!t.isMemberExpression(oldCalleePath.node) && t.isMemberExpression(newCallee)) {
-      newCallee = t.sequenceExpression([
-        t.literal(0),
-        newCallee
-      ]);
-    }
-
-    return finish(t.callExpression(
-      newCallee,
-      path.get("arguments").map(function(argPath) {
-        return explodeViaTempVar(null, argPath);
-      })
-    ));
-
-  case "NewExpression":
-    return finish(t.newExpression(
-      explodeViaTempVar(null, path.get("callee")),
-      path.get("arguments").map(function(argPath) {
-        return explodeViaTempVar(null, argPath);
-      })
-    ));
-
-  case "ObjectExpression":
-    return finish(t.objectExpression(
-      path.get("properties").map(function(propPath) {
-        return t.property(
-          propPath.value.kind,
-          propPath.value.key,
-          explodeViaTempVar(null, propPath.get("value"))
-        );
-      })
-    ));
-
-  case "ArrayExpression":
-    return finish(t.arrayExpression(
-      path.get("elements").map(function(elemPath) {
-        return explodeViaTempVar(null, elemPath);
-      })
-    ));
-
-  case "SequenceExpression":
-    var lastIndex = expr.expressions.length - 1;
-
-    path.get("expressions").each(function(exprPath) {
-      if (exprPath.name === lastIndex) {
-        result = self.explodeExpression(exprPath, ignoreResult);
-      } else {
-        self.explodeExpression(exprPath, true);
-      }
-    });
-
-    return result;
-
-  case "LogicalExpression":
-    after = loc();
-
-    if (!ignoreResult) {
-      result = self.makeTempVar();
-    }
-
-    var left = explodeViaTempVar(result, path.get("left"));
-
-    if (expr.operator === "&&") {
-      self.jumpIfNot(left, after);
-    } else {
-      assert.strictEqual(expr.operator, "||");
-      self.jumpIf(left, after);
-    }
-
-    explodeViaTempVar(result, path.get("right"), ignoreResult);
-
-    self.mark(after);
-
-    return result;
-
-  case "ConditionalExpression":
-    var elseLoc = loc();
-    after = loc();
-    var test = self.explodeExpression(path.get("test"));
-
-    self.jumpIfNot(test, elseLoc);
-
-    if (!ignoreResult) {
-      result = self.makeTempVar();
-    }
-
-    explodeViaTempVar(result, path.get("consequent"), ignoreResult);
-    self.jump(after);
-
-    self.mark(elseLoc);
-    explodeViaTempVar(result, path.get("alternate"), ignoreResult);
-
-    self.mark(after);
-
-    return result;
-
-  case "UnaryExpression":
-    return finish(t.unaryExpression(
-      expr.operator,
-      // Can't (and don't need to) break up the syntax of the argument.
-      // Think about delete a[b].
-      self.explodeExpression(path.get("argument")),
-      !!expr.prefix
-    ));
-
-  case "BinaryExpression":
-    return finish(t.binaryExpression(
-      expr.operator,
-      explodeViaTempVar(null, path.get("left")),
-      explodeViaTempVar(null, path.get("right"))
-    ));
-
-  case "AssignmentExpression":
-    return finish(t.assignmentExpression(
-      expr.operator,
-      self.explodeExpression(path.get("left")),
-      self.explodeExpression(path.get("right"))
-    ));
-
-  case "UpdateExpression":
-    return finish(t.updateExpression(
-      expr.operator,
-      self.explodeExpression(path.get("argument")),
-      expr.prefix
-    ));
-
-  case "YieldExpression":
-    after = loc();
-    var arg = expr.argument && self.explodeExpression(path.get("argument"));
-
-    if (arg && expr.delegate) {
-      result = self.makeTempVar();
-
-      self.emit(t.returnStatement(t.callExpression(
-        self.contextProperty("delegateYield"), [
-          arg,
-          t.literal(result.property.name),
-          after
-        ]
-      )));
-
-      self.mark(after);
-
-      return result;
-    }
-
-    self.emitAssign(self.contextProperty("next"), after);
-    self.emit(t.returnStatement(arg || null));
-    self.mark(after);
-
-    return self.contextProperty("sent");
-
-  default:
+  var fn = explodeExpressions[expr.type];
+  if (fn) {
+    return fn.call(this, expr, path, explodeViaTempVar, finish, ignoreResult);
+  } else {
     throw new Error("unknown Expression of type " + JSON.stringify(expr.type));
   }
 };

lib/6to5/transformation/transformers/generators/hoist.js

@@ -17,7 +17,7 @@ var _      = require("lodash");
 // and replaces any Declaration nodes in its body with assignments, then
 // returns a VariableDeclaration containing just the names of the removed
 // declarations.
-exports.hoist = function(funPath) {
+exports.hoist = function (funPath) {
   assert.ok(funPath instanceof types.NodePath);
   t.assertFunction(funPath.value);
 
@@ -27,7 +27,7 @@ exports.hoist = function(funPath) {
     t.assertVariableDeclaration(vdec);
     var exprs = [];
 
-    vdec.declarations.forEach(function(dec) {
+    vdec.declarations.forEach(function (dec) {
       vars[dec.id.name] = dec.id;
 
       if (dec.init) {
@@ -49,7 +49,7 @@ exports.hoist = function(funPath) {
   }
 
   types.visit(funPath.get("body"), {
-    visitVariableDeclaration: function(path) {
+    visitVariableDeclaration: function (path) {
       var expr = varDeclToExpr(path.value, false);
       if (expr === null) {
         path.replace();
@@ -64,7 +64,7 @@ exports.hoist = function(funPath) {
       return false;
     },
 
-    visitForStatement: function(path) {
+    visitForStatement: function (path) {
       var init = path.value.init;
       if (t.isVariableDeclaration(init)) {
         path.get("init").replace(varDeclToExpr(init, false));
@@ -72,7 +72,7 @@ exports.hoist = function(funPath) {
       this.traverse(path);
     },
 
-    visitForInStatement: function(path) {
+    visitForInStatement: function (path) {
       var left = path.value.left;
       if (t.isVariableDeclaration(left)) {
         path.get("left").replace(varDeclToExpr(left, true));
@@ -80,7 +80,7 @@ exports.hoist = function(funPath) {
       this.traverse(path);
     },
 
-    visitFunctionDeclaration: function(path) {
+    visitFunctionDeclaration: function (path) {
       var node = path.value;
       vars[node.id.name] = node.id;
 
@@ -118,14 +118,14 @@ exports.hoist = function(funPath) {
       return false;
     },
 
-    visitFunctionExpression: function() {
+    visitFunctionExpression: function () {
       // Don't descend into nested function expressions.
       return false;
     }
   });
 
   var paramNames = {};
-  funPath.get("params").each(function(paramPath) {
+  funPath.get("params").each(function (paramPath) {
     var param = paramPath.value;
     if (t.isIdentifier(param)) {
       paramNames[param.name] = param;
@@ -137,7 +137,7 @@ exports.hoist = function(funPath) {
 
   var declarations = [];
 
-  Object.keys(vars).forEach(function(name) {
+  Object.keys(vars).forEach(function (name) {
     if (!_.has(paramNames, name)) {
       declarations.push(t.variableDeclarator(vars[name], null));
     }

lib/6to5/transformation/transformers/generators/leap.js

@@ -124,7 +124,7 @@ function LeapManager(emitter) {
   this.entryStack = [new FunctionEntry(emitter.finalLoc)];
 }
 
-LeapManager.prototype.withEntry = function(entry, callback) {
+LeapManager.prototype.withEntry = function (entry, callback) {
   assert.ok(entry instanceof Entry);
   this.entryStack.push(entry);
   try {
@@ -135,7 +135,7 @@ LeapManager.prototype.withEntry = function(entry, callback) {
   }
 };
 
-LeapManager.prototype._findLeapLocation = function(property, label) {
+LeapManager.prototype._findLeapLocation = function (property, label) {
   for (var i = this.entryStack.length - 1; i >= 0; --i) {
     var entry = this.entryStack[i];
     var loc = entry[property];
@@ -154,10 +154,10 @@ LeapManager.prototype._findLeapLocation = function(property, label) {
   return null;
 };
 
-LeapManager.prototype.getBreakLoc = function(label) {
+LeapManager.prototype.getBreakLoc = function (label) {
   return this._findLeapLocation("breakLoc", label);
 };
 
-LeapManager.prototype.getContinueLoc = function(label) {
+LeapManager.prototype.getContinueLoc = function (label) {
   return this._findLeapLocation("continueLoc", label);
 };

lib/6to5/transformation/transformers/generators/meta.js

@@ -35,7 +35,7 @@ function makePredicate(propertyName, knownTypes) {
       return result;
     }
 
-    types.eachField(node, function(name, child) {
+    types.eachField(node, function (name, child) {
       check(child);
     });
 

lib/6to5/transformation/transformers/generators/runtime.js

@@ -38,19 +38,19 @@ var GFName = "GeneratorFunction";
 if (GF.name !== GFName) GF.name = GFName;
 if (GF.name !== GFName) throw new Error(GFName + " renamed?");
 
-runtime.isGeneratorFunction = function(genFun) {
+runtime.isGeneratorFunction = function (genFun) {
   var ctor = genFun && genFun.constructor;
   return ctor ? GF.name === ctor.name : false;
 };
 
-runtime.mark = function(genFun) {
+runtime.mark = function (genFun) {
   genFun.__proto__ = GFp;
   genFun.prototype = Object.create(Gp);
   return genFun;
 };
 
-runtime.async = function(innerFn, outerFn, self, tryList) {
-  return new Promise(function(resolve, reject) {
+runtime.async = function (innerFn, outerFn, self, tryList) {
+  return new Promise(function (resolve, reject) {
     var generator = wrap(innerFn, outerFn, self, tryList);
     var callNext = step.bind(generator.next);
     var callThrow = step.bind(generator["throw"]);
@@ -202,11 +202,11 @@ function Generator(innerFn, outerFn, self, tryList) {
   return generator;
 }
 
-Gp[iteratorSymbol] = function() {
+Gp[iteratorSymbol] = function () {
   return this;
 };
 
-Gp.toString = function() {
+Gp.toString = function () {
   return "[object Generator]";
 };
 
@@ -240,7 +240,7 @@ function Context(tryList) {
   this.reset();
 }
 
-runtime.keys = function(object) {
+runtime.keys = function (object) {
   var keys = [];
   for (var key in object) {
     keys.push(key);
@@ -293,7 +293,7 @@ runtime.values = values;
 Context.prototype = {
   constructor: Context,
 
-  reset: function() {
+  reset: function () {
     this.prev = 0;
     this.next = 0;
     this.sent = undefined;
@@ -311,7 +311,7 @@ Context.prototype = {
     }
   },
 
-  stop: function() {
+  stop: function () {
     this.done = true;
 
     var rootEntry = this.tryEntries[0];
@@ -323,7 +323,7 @@ Context.prototype = {
     return this.rval;
   },
 
-  dispatchException: function(exception) {
+  dispatchException: function (exception) {
     if (this.done) {
       throw exception;
     }
@@ -375,7 +375,7 @@ Context.prototype = {
     }
   },
 
-  _findFinallyEntry: function(finallyLoc) {
+  _findFinallyEntry: function (finallyLoc) {
     for (var i = this.tryEntries.length - 1; i >= 0; --i) {
       var entry = this.tryEntries[i];
       if (entry.tryLoc <= this.prev &&
@@ -387,7 +387,7 @@ Context.prototype = {
     }
   },
 
-  abrupt: function(type, arg) {
+  abrupt: function (type, arg) {
     var entry = this._findFinallyEntry();
     var record = entry ? entry.completion : {};
 
@@ -403,7 +403,7 @@ Context.prototype = {
     return ContinueSentinel;
   },
 
-  complete: function(record) {
+  complete: function (record) {
     if (record.type === "throw") {
       throw record.arg;
     }
@@ -418,12 +418,12 @@ Context.prototype = {
     return ContinueSentinel;
   },
 
-  finish: function(finallyLoc) {
+  finish: function (finallyLoc) {
     var entry = this._findFinallyEntry(finallyLoc);
     return this.complete(entry.completion);
   },
 
-  "catch": function(tryLoc) {
+  "catch": function (tryLoc) {
     for (var i = this.tryEntries.length - 1; i >= 0; --i) {
       var entry = this.tryEntries[i];
       if (entry.tryLoc === tryLoc) {
@@ -442,7 +442,7 @@ Context.prototype = {
     throw new Error("illegal catch attempt");
   },
 
-  delegateYield: function(iterable, resultName, nextLoc) {
+  delegateYield: function (iterable, resultName, nextLoc) {
     this.delegate = {
       iterator: values(iterable),
       resultName: resultName,

lib/6to5/transformation/transformers/generators/util.js

@@ -16,3 +16,13 @@ exports.runtimeProperty = function (name) {
     t.identifier(name)
   );
 };
+
+// Offsets into this.listing that could be used as targets for branches or
+// jumps are represented as numeric Literal nodes. This representation has
+// the amazingly convenient benefit of allowing the exact value of the
+// location to be determined at any time, even after generating code that
+// refers to the location.
+
+exports.loc = function () {
+  return t.literal(-1);
+};

lib/6to5/transformation/transformers/generators/visit.js

@@ -23,7 +23,7 @@ exports.transform = function transform(node) {
 };
 
 var visitor = types.PathVisitor.fromMethodsObject({
-  visitFunction: function(path) {
+  visitFunction: function (path) {
     // Calling this.traverse(path) first makes for a post-order traversal.
     this.traverse(path);
 
@@ -156,12 +156,12 @@ var visitor = types.PathVisitor.fromMethodsObject({
         )
       ]);
 
-      if (node.comments) {
-        // Copy any comments preceding the function declaration to the
-        // variable declaration, to avoid weird formatting consequences.
-        varDecl.comments = node.comments;
-        node.comments = null;
-      }
+      // Copy any comments preceding the function declaration to the
+      // variable declaration, to avoid weird formatting consequences.
+      t.inheritsComments(varDecl, node);
+      t.removeComments(node);
+
+      varDecl._blockHoist = true;
 
       var bodyPath = pp.get("body");
       var bodyLen = bodyPath.value.length;
@@ -175,7 +175,6 @@ var visitor = types.PathVisitor.fromMethodsObject({
       }
 
       bodyPath.push(varDecl);
-
     } else {
       t.assertFunctionExpression(node);
       return t.callExpression(runtimeMarkMethod, [node]);
@@ -208,11 +207,11 @@ function shouldNotHoistAbove(stmtPath) {
 }
 
 var awaitVisitor = types.PathVisitor.fromMethodsObject({
-  visitFunction: function() {
+  visitFunction: function () {
     return false; // Don't descend into nested function scopes.
   },
 
-  visitAwaitExpression: function(path) {
+  visitAwaitExpression: function (path) {
     // Convert await expressions to yield expressions.
     return t.yieldExpression(path.value.argument, false);
   }

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

@@ -1,13 +1,13 @@
-var t = require("../../types");
-var _ = require("lodash");
+var util = require("../../util");
+var t    = require("../../types");
+var _    = require("lodash");
 
 var getSpreadLiteral = function (spread) {
   var literal = spread.argument;
   if (!t.isArrayExpression(literal)) {
-    literal = t.callExpression(
-      t.memberExpression(t.identifier("Array"), t.identifier("from")),
-      [literal]
-    );
+    literal = util.template("array-from", {
+      VALUE: literal
+    });
   }
   return literal;
 };

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

@@ -22,9 +22,7 @@ exports.TaggedTemplateExpression = function (node, parent, file) {
     t.arrayExpression(raw)
   ]));
 
-  _.each(quasi.expressions, function (expr) {
-    args.push(expr);
-  });
+  args = args.concat(quasi.expressions);
 
   return t.callExpression(node.tag, args);
 };

lib/6to5/types/index.js

@@ -250,6 +250,11 @@ t.inheritsComments = function (child, parent) {
   return child;
 };
 
+t.removeComments = function (node) {
+  delete node.leadingComments;
+  delete node.trailingComments;
+};
+
 t.inherits = function (child, parent) {
   child.loc   = parent.loc;
   child.end   = parent.end;

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "1.12.21",
+  "version": "1.12.23",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -37,14 +37,14 @@
   "dependencies": {
     "ast-types": "~0.6.0",
     "commander": "2.5.0",
-    "fs-readdir-recursive": "0.0.2",
+    "fs-readdir-recursive": "0.1.0",
     "lodash": "2.4.1",
     "mkdirp": "0.5.0",
     "es6-shim": "0.20.2",
     "es6-symbol": "0.1.1",
     "regexpu": "0.3.0",
     "source-map": "0.1.40",
-    "chokidar": "0.10.5",
+    "chokidar": "0.11.0",
     "source-map-support": "0.2.8",
     "esutils": "1.1.4",
     "acorn-6to5": "0.9.1-2",

test/fixtures/transformation/api/blacklist/expected.js

@@ -2,4 +2,4 @@
 
 var Test = function Test() {
   arr.map(x => x * x);
-};
+};

test/fixtures/transformation/array-comprehension/array-expression-single/expected.js

@@ -2,4 +2,4 @@
 
 var arr = [1, 2, 3].map(function (i) {
   return i * i;
-});
+});

test/fixtures/transformation/arrow-functions/destructuring-parameters/expected.js

@@ -4,4 +4,4 @@ var a = function (_ref) {
   var target = _ref.target;
   return console.log(target);
 };
-a({ target: "I am a target" });
+a({ target: "I am a target" });

test/fixtures/transformation/arrow-functions/empty-arguments/expected.js

@@ -2,4 +2,4 @@
 
 var t = function () {
   return 5 + 5;
-};
+};

test/fixtures/transformation/arrow-functions/empty-block/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var t = function () {};
+var t = function () {};

test/fixtures/transformation/arrow-functions/expression/expected.js

@@ -2,4 +2,4 @@
 
 arr.map(function (x) {
   return x * x;
-});
+});

test/fixtures/transformation/arrow-functions/inside-call/expected.js

@@ -2,4 +2,4 @@
 
 arr.map(function (i) {
   return i + 1;
-});
+});

test/fixtures/transformation/arrow-functions/multiple-arguments/expected.js

@@ -2,4 +2,4 @@
 
 var t = function (i, x) {
   return i * x;
-};
+};

test/fixtures/transformation/arrow-functions/paran-insertion/expected.js

@@ -2,4 +2,4 @@
 
 var t = function (i) {
   return i * 5;
-};
+};

test/fixtures/transformation/arrow-functions/single-argument/expected.js

@@ -2,4 +2,4 @@
 
 var t = function (i) {
   return i * 5;
-};
+};

test/fixtures/transformation/arrow-functions/statement/expected.js

@@ -4,4 +4,4 @@ nums.forEach(function (v) {
   if (v % 5 === 0) {
     fives.push(v);
   }
-});
+});

test/fixtures/transformation/arrow-functions/this/expected.js

@@ -3,4 +3,4 @@
 var _this = this;
 var t = function (x) {
   return _this.x + x;
-};
+};

test/fixtures/transformation/classes/plain-class/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var Test = function Test() {};
+var Test = function Test() {};

test/fixtures/transformation/classes/super-function-fallback/expected.js

@@ -2,4 +2,4 @@
 
 var Test = function Test() {
   Function.prototype.hasOwnProperty.call(this, "test");
-};
+};

test/fixtures/transformation/computed-property-names/argument/expected.js

@@ -3,4 +3,4 @@
 foo((function (_ref) {
   _ref[bar] = "foobar";
   return _ref;
-})({}));
+})({}));

test/fixtures/transformation/computed-property-names/assignment/expected.js

@@ -3,4 +3,4 @@
 foo = (function (_foo) {
   _foo[bar] = "foobar";
   return _foo;
-})({});
+})({});

test/fixtures/transformation/computed-property-names/method/expected.js

@@ -5,4 +5,4 @@ var obj = (function (_obj) {
     return "foobar";
   };
   return _obj;
-})({});
+})({});

test/fixtures/transformation/computed-property-names/mixed/expected.js

@@ -7,4 +7,4 @@ var obj = (function (_obj) {
 })({
   foo: "foo",
   bar: "bar"
-});
+});

test/fixtures/transformation/computed-property-names/multiple/expected.js

@@ -4,4 +4,4 @@ var obj = (function (_obj) {
   _obj["x" + foo] = "heh";
   _obj["y" + bar] = "noo";
   return _obj;
-})({});
+})({});

test/fixtures/transformation/computed-property-names/single/expected.js

@@ -3,4 +3,4 @@
 var obj = (function (_obj) {
   _obj["x" + foo] = "heh";
   return _obj;
-})({});
+})({});

test/fixtures/transformation/computed-property-names/this/expected.js

@@ -4,4 +4,4 @@ var _this = this;
 var obj = (function (_obj) {
   _obj["x" + _this.foo] = "heh";
   return _obj;
-})({});
+})({});

test/fixtures/transformation/computed-property-names/variable/expected.js

@@ -3,4 +3,4 @@
 var foo = (function (_foo) {
   _foo[bar] = "foobar";
   return _foo;
-})({});
+})({});

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

@@ -2,15 +2,19 @@
 
 var _ref = [1, 2];
 
-var a = _ref[0];
-var b = _ref[1];
-var _ref2 = [3, 4];
+var _ref2 = Array.from(_ref);
 
-var c = _ref2[0];
-var d = _ref2[1];
-var _ref3 = { e: 5, f: 6 };
-var e = _ref3.e;
-var f = _ref3.f;
-var _ref4 = { a: 7, b: 8 };
-var g = _ref4.a;
-var h = _ref4.b;
+var a = _ref2[0];
+var b = _ref2[1];
+var _ref3 = [3, 4];
+
+var _ref4 = Array.from(_ref3);
+
+var c = _ref4[0];
+var d = _ref4[1];
+var _ref5 = { e: 5, f: 6 };
+var e = _ref5.e;
+var f = _ref5.f;
+var _ref6 = { a: 7, b: 8 };
+var g = _ref6.a;
+var h = _ref6.b;

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

@@ -2,7 +2,13 @@
 
 var _ref = ["hello", [", ", "junk"], ["world"]];
 
-var a = _ref[0];
-var b = _ref[1][0];
-var c = _ref[2][0];
-var d = _ref[3];
+var _ref2 = Array.from(_ref);
+
+var a = _ref2[0];
+var _ref3 = Array.from(_ref2[1]);
+
+var b = _ref3[0];
+var _ref4 = Array.from(_ref2[2]);
+
+var c = _ref4[0];
+var d = _ref2[3];

test/fixtures/transformation/destructuring/assignment-statement/expected.js

@@ -2,5 +2,7 @@
 
 var _ref = f();
 
-a = _ref[0];
-b = _ref[1];
+var _ref2 = Array.from(_ref);
+
+a = _ref2[0];
+b = _ref2[1];

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

@@ -2,7 +2,13 @@
 
 var _ref = ["foo", "hello", [", ", "junk"], ["world"]];
 
-var a = _ref[1];
-var b = _ref[2][0];
-var c = _ref[3][0];
-var d = _ref[4];
+var _ref2 = Array.from(_ref);
+
+var a = _ref2[1];
+var _ref3 = Array.from(_ref2[2]);
+
+var b = _ref3[0];
+var _ref4 = Array.from(_ref2[3]);
+
+var c = _ref4[0];
+var d = _ref2[4];

test/fixtures/transformation/destructuring/for-in/expected.js

@@ -1,7 +1,9 @@
 "use strict";
 
 for (var _ref in obj) {
-  var name = _ref[0];
-  var value = _ref[1];
+  var _ref2 = Array.from(_ref);
+
+  var name = _ref2[0];
+  var value = _ref2[1];
   print("Name: " + name + ", Value: " + value);
 }

test/fixtures/transformation/destructuring/for-of/expected.js

@@ -2,7 +2,9 @@
 
 for (var _iterator = this.test.expectation.registers[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
   var _ref = _step.value;
-  var name = _ref[0];
-  var before = _ref[1];
-  var after = _ref[2];
-}
+  var _ref2 = Array.from(_ref);
+
+  var name = _ref2[0];
+  var before = _ref2[1];
+  var after = _ref2[2];
+}

test/fixtures/transformation/destructuring/member-expression/expected.js

@@ -2,5 +2,7 @@
 
 var _ref = [1, 2];
 
-this.foo = _ref[0];
-this.bar = _ref[1];
+var _ref2 = Array.from(_ref);
+
+this.foo = _ref2[0];
+this.bar = _ref2[1];

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

@@ -1,6 +1,10 @@
 "use strict";
 
-var x1 = rect.topLeft[0];
-var y1 = rect.topLeft[1];
-var x2 = rect.bottomRight[0];
-var y2 = rect.bottomRight[1];
+var _ref = Array.from(rect.topLeft);
+
+var x1 = _ref[0];
+var y1 = _ref[1];
+var _ref2 = Array.from(rect.bottomRight);
+
+var x2 = _ref2[0];
+var y2 = _ref2[1];

test/fixtures/transformation/destructuring/multiple/expected.js

@@ -2,4 +2,4 @@
 
 var x = coords.x;
 var y = coords.y;
-var foo = "bar";
+var foo = "bar";

test/fixtures/transformation/destructuring/object-advanced/expected.js

@@ -3,4 +3,4 @@
 var x1 = rect.topLeft.x;
 var y1 = rect.topLeft.y;
 var x2 = rect.bottomRight.x;
-var y2 = rect.bottomRight.y;
+var y2 = rect.bottomRight.y;

test/fixtures/transformation/destructuring/object-basic/expected.js

@@ -1,4 +1,4 @@
 "use strict";
 
 var x = coords.x;
-var y = coords.y;
+var y = coords.y;

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

@@ -15,13 +15,17 @@ function unpackObject(_ref2) {
 
 console.log(unpackObject({ title: "title", author: "author" }));
 
-var unpackArray = function (_ref3, _ref4) {
-  var a = _ref3[0];
-  var b = _ref3[1];
-  var c = _ref3[2];
-  var x = _ref4[0];
-  var y = _ref4[1];
-  var z = _ref4[2];
+var unpackArray = function (_ref3, _ref5) {
+  var _ref4 = Array.from(_ref3);
+
+  var a = _ref4[0];
+  var b = _ref4[1];
+  var c = _ref4[2];
+  var _ref6 = Array.from(_ref5);
+
+  var x = _ref6[0];
+  var y = _ref6[1];
+  var z = _ref6[2];
   return a + b + c;
 };
 

test/fixtures/transformation/destructuring/spread-generator/exec.js

@@ -0,0 +1,7 @@
+function* f() {
+  for (var i = 0; i < 3; i++) {
+    yield i;
+  }
+}
+var [...xs] = f();
+assert.deepEqual(xs, [0, 1, 2]);

test/fixtures/transformation/destructuring/spread/expected.js

@@ -1,9 +1,11 @@
 "use strict";
 
 var isSorted = function (_ref) {
-  var x = _ref[0];
-  var y = _ref[1];
-  var wow = _ref.slice(2);
+  var _ref2 = Array.from(_ref);
+
+  var x = _ref2[0];
+  var y = _ref2[1];
+  var wow = Array.from(_ref2).slice(2);
 
   if (!zs.length) return true;
   if (y > x) return isSorted(zs);

test/fixtures/transformation/for-of/identifier/expected.js

@@ -2,4 +2,4 @@
 
 for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
   i = _step.value;
-}
+}

test/fixtures/transformation/for-of/var/expected.js

@@ -2,4 +2,4 @@
 
 for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
   var i = _step.value;
-}
+}

test/fixtures/transformation/modules-amd/exports-default/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/exports-default/expected", ["exports"], function (exports) {
+define(["exports"], function (exports) {
   "use strict";
 
   exports["default"] = 42;
@@ -12,4 +12,4 @@ define("modules-amd/exports-default/expected", ["exports"], function (exports) {
   var Foo = function Foo() {};
 
   exports["default"] = Foo;
-});
+});

test/fixtures/transformation/modules-amd/exports-from/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/exports-from/expected", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   (function (obj) {
@@ -14,4 +14,4 @@ define("modules-amd/exports-from/expected", ["exports", "foo"], function (export
   exports["default"] = _foo.foo;
   exports["default"] = _foo.foo;
   exports.bar = _foo.bar;
-});
+});

test/fixtures/transformation/modules-amd/exports-named/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/exports-named/expected", ["exports"], function (exports) {
+define(["exports"], function (exports) {
   "use strict";
 
   exports.foo = foo;
@@ -8,4 +8,4 @@ define("modules-amd/exports-named/expected", ["exports"], function (exports) {
   exports["default"] = foo;
   exports["default"] = foo;
   exports.bar = bar;
-});
+});

test/fixtures/transformation/modules-amd/exports-variable/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/exports-variable/expected", ["exports"], function (exports) {
+define(["exports"], function (exports) {
   "use strict";
 
   exports.foo7 = foo7;
@@ -12,4 +12,4 @@ define("modules-amd/exports-variable/expected", ["exports"], function (exports)
   var foo8 = function foo8() {};
 
   exports.foo8 = foo8;
-});
+});

test/fixtures/transformation/modules-amd/hoist-function-exports/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/hoist-function-exports/expected", ["exports", "./evens"], function (exports, _evens) {
+define(["exports", "./evens"], function (exports, _evens) {
   "use strict";
 
   exports.nextOdd = nextOdd;
@@ -12,4 +12,4 @@ define("modules-amd/hoist-function-exports/expected", ["exports", "./evens"], fu
       return !isEven(n);
     };
   })(isEven);
-});
+});

test/fixtures/transformation/modules-amd/imports-default/expected.js

@@ -1,6 +1,6 @@
-define("modules-amd/imports-default/expected", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var foo = _foo["default"];
   var foo = _foo["default"];
-});
+});

test/fixtures/transformation/modules-amd/imports-glob/expected.js

@@ -1,5 +1,5 @@
-define("modules-amd/imports-glob/expected", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var foo = _foo;
-});
+});

test/fixtures/transformation/modules-amd/imports-mixing/expected.js

@@ -1,6 +1,6 @@
-define("modules-amd/imports-mixing/expected", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var foo = _foo["default"];
   var xyz = _foo.baz;
-});
+});

test/fixtures/transformation/modules-amd/imports-named/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/imports-named/expected", ["exports", "foo"], function (exports, _foo) {
+define(["exports", "foo"], function (exports, _foo) {
   "use strict";
 
   var bar = _foo.bar;
@@ -7,4 +7,4 @@ define("modules-amd/imports-named/expected", ["exports", "foo"], function (expor
   var baz = _foo.bar;
   var baz = _foo.bar;
   var xyz = _foo.xyz;
-});
+});

test/fixtures/transformation/modules-amd/imports/expected.js

@@ -1,3 +1,3 @@
-define("modules-amd/imports/expected", ["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
+define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
   "use strict";
-});
+});

test/fixtures/transformation/modules-amd/overview/expected.js

@@ -1,4 +1,4 @@
-define("modules-amd/overview/expected", ["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
+define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
   "use strict";
 
   var foo = _foo["default"];
@@ -9,4 +9,4 @@ define("modules-amd/overview/expected", ["exports", "foo", "foo-bar", "./directo
   var test = exports.test = 5;
 
   exports["default"] = test;
-});
+});

test/fixtures/transformation/modules-common-interop/imports-glob/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = require("foo");
+var foo = require("foo");

test/fixtures/transformation/modules-common-interop/imports-named/expected.js

@@ -5,4 +5,4 @@ var bar = require("foo").bar;
 var baz = require("foo").baz;
 var baz = require("foo").bar;
 var baz = require("foo").bar;
-var xyz = require("foo").xyz;
+var xyz = require("foo").xyz;

test/fixtures/transformation/modules-common/imports-glob/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = require("foo");
+var foo = require("foo");

test/fixtures/transformation/modules-common/imports-named/expected.js

@@ -5,4 +5,4 @@ var bar = require("foo").bar;
 var baz = require("foo").baz;
 var baz = require("foo").bar;
 var baz = require("foo").bar;
-var xyz = require("foo").xyz;
+var xyz = require("foo").xyz;

test/fixtures/transformation/modules-umd/exports-default/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/exports-default/expected", ["exports"], factory);
+    define(["exports"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports);
   }
@@ -18,4 +18,4 @@
   var Foo = function Foo() {};
 
   exports["default"] = Foo;
-});
+});

test/fixtures/transformation/modules-umd/exports-from/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/exports-from/expected", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }
@@ -20,4 +20,4 @@
   exports["default"] = _foo.foo;
   exports["default"] = _foo.foo;
   exports.bar = _foo.bar;
-});
+});

test/fixtures/transformation/modules-umd/exports-named/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/exports-named/expected", ["exports"], factory);
+    define(["exports"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports);
   }
@@ -14,4 +14,4 @@
   exports["default"] = foo;
   exports["default"] = foo;
   exports.bar = bar;
-});
+});

test/fixtures/transformation/modules-umd/exports-variable/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/exports-variable/expected", ["exports"], factory);
+    define(["exports"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports);
   }
@@ -18,4 +18,4 @@
   var foo8 = function foo8() {};
 
   exports.foo8 = foo8;
-});
+});

test/fixtures/transformation/modules-umd/hoist-function-exports/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/hoist-function-exports/expected", ["exports", "./evens"], factory);
+    define(["exports", "./evens"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("./evens"));
   }
@@ -18,4 +18,4 @@
       return !isEven(n);
     };
   })(isEven);
-});
+});

test/fixtures/transformation/modules-umd/imports-default/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/imports-default/expected", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }
@@ -9,4 +9,4 @@
 
   var foo = _foo["default"];
   var foo = _foo["default"];
-});
+});

test/fixtures/transformation/modules-umd/imports-glob/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/imports-glob/expected", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }
@@ -8,4 +8,4 @@
   "use strict";
 
   var foo = _foo;
-});
+});

test/fixtures/transformation/modules-umd/imports-mixing/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/imports-mixing/expected", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }
@@ -9,4 +9,4 @@
 
   var foo = _foo["default"];
   var xyz = _foo.baz;
-});
+});

test/fixtures/transformation/modules-umd/imports-named/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/imports-named/expected", ["exports", "foo"], factory);
+    define(["exports", "foo"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"));
   }
@@ -13,4 +13,4 @@
   var baz = _foo.bar;
   var baz = _foo.bar;
   var xyz = _foo.xyz;
-});
+});

test/fixtures/transformation/modules-umd/imports/expected.js

@@ -1,9 +1,9 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/imports/expected", ["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
+    define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
 })(function (exports, _foo, _fooBar, _directoryFooBar) {
   "use strict";
-});
+});

test/fixtures/transformation/modules-umd/overview/expected.js

@@ -1,6 +1,6 @@
 (function (factory) {
   if (typeof define === "function" && define.amd) {
-    define("modules-umd/overview/expected", ["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
+    define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
@@ -15,4 +15,4 @@
   var test = exports.test = 5;
 
   exports["default"] = test;
-});
+});

test/fixtures/transformation/property-name-shorthand/single/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var coords = { x: x };
+var coords = { x: x };

test/fixtures/transformation/source-maps/arrow-function/expected.js

@@ -2,4 +2,4 @@
 
 var t = function (x) {
   return x * x;
-};
+};

test/fixtures/transformation/source-maps/full/expected.js

@@ -2,4 +2,4 @@
 
 arr.map(function (x) {
   return x * x;
-});
+});

test/fixtures/transformation/spread/method-call-array-literal/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-f.apply(null, [1, 2, 3]);
+f.apply(null, [1, 2, 3]);

test/fixtures/transformation/template-literals/escape-quotes/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var t = "'" + foo + "' \"" + bar + "\"";
+var t = "'" + foo + "' \"" + bar + "\"";

test/fixtures/transformation/template-literals/functions/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = "test " + _.test(foo) + " " + bar;
+var foo = "test " + _.test(foo) + " " + bar;

test/fixtures/transformation/template-literals/multiline/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var o = "wow\nthis is\nactually multiline!";
+var o = "wow\nthis is\nactually multiline!";

test/fixtures/transformation/template-literals/multiple/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = "test " + foo + " " + bar;
+var foo = "test " + foo + " " + bar;

test/fixtures/transformation/template-literals/none/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = "test";
+var foo = "test";

test/fixtures/transformation/template-literals/only/expected.js

@@ -1,3 +1,3 @@
 "use strict";
 
-var foo = "" + test;
+var foo = "" + test;