diff --git a/lib/configParser.js b/lib/configParser.js
index c5ed62e15..45c470bb7 100644
--- a/lib/configParser.js
+++ b/lib/configParser.js
@@ -133,7 +133,7 @@ ConfigParser.prototype.addConfig_ = function(additionalConfig, relativeTo) {
  */
 ConfigParser.prototype.addFileConfig = function(filename) {
   if (!filename) {
-    return;
+    return this;
   }
   var filePath = path.resolve(process.cwd(), filename);
   var fileConfig = require(filePath).config;