diff --git a/src/components/fields/FunctionSpecField.jsx b/src/components/fields/FunctionSpecField.jsx
index 75214df..e2542c5 100644
--- a/src/components/fields/FunctionSpecField.jsx
+++ b/src/components/fields/FunctionSpecField.jsx
@@ -18,7 +18,7 @@ function isDataField(value) {
  * If we don't have a default value just make one up
  */
 function findDefaultFromSpec (spec) {
-  if (spec.default) {
+  if (spec.hasOwnProperty('default')) {
     return spec.default;
   }