diff --git a/lib/file.js b/lib/file.js
index 01fb60f6..3213f4dd 100644
--- a/lib/file.js
+++ b/lib/file.js
@@ -14,7 +14,7 @@ exports.appendFile = function(file, content) {
 
 exports.writeFile = function(file, content) {
   const parts = path.parse(file);
-  if (!fs.existsSync(parts.dir)) {
+  if (parts.dir !== '' && !fs.existsSync(parts.dir)) {
     fs.mkdirSync(parts.dir, { recursive: true });
   }
   // TODO(joyeecheung): what if the file is a dir?