diff --git a/src/lib/taxcalc.js b/src/lib/taxcalc.js
index 77dcce7f..1bbd19c0 100644
--- a/src/lib/taxcalc.js
+++ b/src/lib/taxcalc.js
@@ -1,7 +1,7 @@
 function isSpecialPriceActive(fromDate, toDate) {
   const now = new Date()
-  fromDate = new Date(fromDate) || false
-  toDate = new Date(toDate) || false
+  fromDate = fromDate ? new Date(fromDate) : false
+  toDate = toDate ? new Date(toDate) : false
 
   if (!fromDate && !toDate) {
     return true