support nested arrow functions - fixes #60

lib/6to5/transformers/_alias-functions.js

@@ -29,6 +29,12 @@ var go = function (getBody, node, file) {
 
     // traverse all child nodes of this function and find arguments and this
     traverse(node, function (node, parent) {
+      if (_aliasFunction === "arrows") {
+        if (traverse.isFunction(node) && node._aliasFunction !== "arrows") {
+          return false;
+        }
+      }
+
       var getId;
 
       if (node.type === "Identifier" && node.name === "arguments") {
@@ -40,7 +46,7 @@ var go = function (getBody, node, file) {
       }
 
       if (util.isReferenced(node, parent)) return getId();
-    }, _aliasFunction === "arrows" && ["FunctionExpression", "FunctionDeclaration"]);
+    });
 
     return false;
   });

test/fixtures/syntax/arrow-functions/nested/actual.js

@@ -0,0 +1,13 @@
+module.exports = {
+  init() {
+    return new Promise((resolve, reject) => {
+      MongoClient.connect(config.mongodb, (err, db) => {
+        if (err) {
+          return reject(err);
+        }
+        this.db = db;
+        resolve(this);
+      });
+    });
+  }
+};

test/fixtures/syntax/arrow-functions/nested/expected.js

@@ -0,0 +1,14 @@
+module.exports = {
+  init: function() {
+    var _this = this;
+    return new Promise(function(resolve, reject) {
+      MongoClient.connect(config.mongodb, function(err, db) {
+        if (err) {
+          return reject(err);
+        }
+        _this.db = db;
+        resolve(_this);
+      });
+    });
+  }
+};