diff --git a/lib/6to5/generator.js b/lib/6to5/generator.js
index 1b3f60cd14..6f83d625c7 100644
--- a/lib/6to5/generator.js
+++ b/lib/6to5/generator.js
@@ -56,6 +56,7 @@ CodeGenerator.prototype.mark = function (node, type) {
 
 CodeGenerator.prototype.newline = function (i, removeLast) {
   if (!this.buf) return;
+  if (this.endsWith("{\n")) return;
 
   if (_.isBoolean(i)) {
     removeLast = i;
@@ -159,6 +160,10 @@ CodeGenerator.prototype._push = function (str) {
   this.buf += str;
 };
 
+CodeGenerator.prototype.endsWith = function (str) {
+  return this.buf.slice(-str.length) === str;
+};
+
 CodeGenerator.prototype.isLast = function (cha, trimRight) {
   var buf = this.buf;
   if (trimRight) buf = buf.trimRight();
@@ -189,7 +194,6 @@ CodeGenerator.prototype.generate = function () {
   this.print(ast);
 
   this.buf = this.buf.trimRight();
-  this.buf = this.buf.replace(/\{\n\n/g, "{\n");
 
   var map = this.map;
   if (map) map = map.toJSON();