diff --git a/lib/reparse.js b/lib/reparse.js
index 7729e99..3751dad 100644
--- a/lib/reparse.js
+++ b/lib/reparse.js
@@ -111,10 +111,10 @@
         return this.fail();
       }
       this.input = this.input.substr(((probe[1] != null) && putback ? probe[1].length : probe[0].length));
-      if (probe[1] != null) {
-        return probe[1];
-      } else {
+      if (probe[1] === undefined) {
         return probe[0];
+      } else {
+        return probe[1];
       }
     };
 
diff --git a/src/reparse.coffee b/src/reparse.coffee
index 0943f3d..408e7e4 100644
--- a/src/reparse.coffee
+++ b/src/reparse.coffee
@@ -79,7 +79,7 @@ exports.ReParse = class ReParse
         probe = @input.match pattern
         return @fail()  unless probe
         @input = @input.substr (if probe[1]? and putback then probe[1].length else probe[0].length)
-        if probe[1]? then probe[1] else probe[0]
+        if probe[1] is `undefined` then probe[0] else probe[1]
 
     # Attempts to apply the method and produce a value.  If it fails,
     # restores the input to the previous state.