diff --git a/lib/layouts.js b/lib/layouts.js
index aed65b8..931fc48 100644
--- a/lib/layouts.js
+++ b/lib/layouts.js
@@ -236,7 +236,7 @@ function patternLayout (pattern, tokens) {
 		    replacement = "%";
 		    break;
 		case "x":
-			if(tokens[specifier]) {
+			if(typeof(tokens[specifier]) !== 'undefined') {
 				if(typeof(tokens[specifier]) === 'function') {
 					replacement = tokens[specifier]();
 				} else {