diff --git a/src/validators/format.js b/src/validators/format.js
index 9f588e68..398ed8d3 100755
--- a/src/validators/format.js
+++ b/src/validators/format.js
@@ -6,7 +6,7 @@ const semver = require('semver');
  * @return {boolean}      True if the string is lowercase or is missing. False if it is not.
  */
 const isLowercase = name => {
-  if (typeof name === 'undefined') {
+  if (typeof name !== 'string') {
     return true;
   }