GH-455 - Parse upper and lower into numbers to appropriately test the…

…ir ranges.

Signed-off-by: Nick Campbell <nicholas.j.campbell@gmail.com>

lib/cron.js

@@ -454,11 +454,14 @@
 			for (var i = 0; i < allRanges.length; i++) {
 				if (allRanges[i].match(rangePattern)) {
 					allRanges[i].replace(rangePattern, function($0, lower, upper, step) {
-						const wasStepDefined = !isNaN(parseInt(step));
+						lower = parseInt(lower, 10);
+						upper = parseInt(upper, 10) || undefined;
+
+						const wasStepDefined = !isNaN(parseInt(step, 10));
 						if (step === '0') {
 							throw new Error('Field (' + field + ') has a step of zero');
 						}
-						step = parseInt(step) || 1;
+						step = parseInt(step, 10) || 1;
 
 						if (upper && lower > upper) {
 							throw new Error('Field (' + field + ') has an invalid range');