add generators support via regenerator

lib/6to5/file.js

@@ -91,6 +91,7 @@ File.prototype.transform = function (ast) {
   var result = util.generate(ast, opts);
 
   if (this.shebang) {
+    // add back shebang
     result.code = this.shebang + result.code;
   }
 

lib/6to5/polyfill.js

@@ -1,2 +1,3 @@
 require("es6-symbol/implement");
 require("es6-shim");
+global.regeneratorRuntime = require("regenerator/runtime");

lib/6to5/transform.js

@@ -30,6 +30,7 @@ transform.test = function (task, assert) {
   actualCode       = recast.prettyPrint(actualAst).code;
 
   if (exec) {
+    require("./polyfill");
     var fn = new Function("assert", actualCode);
     fn(assert);
   }
@@ -79,12 +80,12 @@ transform.transformers = {
   templateLiterals:         require("./transformers/template-literals"),
   propertyMethodAssignment: require("./transformers/property-method-assignment"),
   defaultParameters:        require("./transformers/default-parameters"),
-  generators:               require("./transformers/generators"),
   letScoping:               require("./transformers/let-scoping"),
   restParameters:           require("./transformers/rest-parameters"),
   destructuring:            require("./transformers/destructuring"),
   forOf:                    require("./transformers/for-of"),
   unicodeRegex:             require("./transformers/unicode-regex"),
+  generators:               require("./transformers/generators"),
 
   _aliasFunctions:          require("./transformers/_alias-functions")
 };

lib/6to5/transformer.js

@@ -9,10 +9,14 @@ function Transformer(key, transformer) {
 }
 
 Transformer.normalise = function (transformer) {
-  _.each(transformer, function (fns, type) {
-    if (_.isFunction(fns)) fns = { enter: fns };
-    transformer[type] = fns;
-  });
+  if (_.isFunction(transformer)) {
+    transformer = { ast: transformer };
+  } else {
+    _.each(transformer, function (fns, type) {
+      if (_.isFunction(fns)) fns = { enter: fns };
+      transformer[type] = fns;
+    });
+  }
   return transformer;
 };
 
@@ -20,6 +24,11 @@ Transformer.prototype.transform = function (file) {
   if (!this.canRun(file)) return;
 
   var transformer = this.transformer;
+  var ast         = file.ast;
+
+  if (transformer.ast) {
+    transformer.ast(ast);
+  }
 
   var build = function (exit) {
     return function (node, parent) {
@@ -43,7 +52,7 @@ Transformer.prototype.transform = function (file) {
     };
   };
 
-  traverse(file.ast, {
+  traverse(ast, {
     enter: build(),
     exit:  build(true)
   });

lib/6to5/transformers/generators.js

@@ -0,0 +1,3 @@
+var regenerator = require("regenerator");
+
+module.exports = regenerator.transform;