invalid date catch in patternfly date adapter (#224)

* invalid date catch in patternfly date adapter

* added null end_date check when calculating retirement date

* fixed date instance check

src/common/patternfly_date_adapter.tsx

@@ -1,10 +1,10 @@
-import { format as formatDate, parse as parseDate } from 'date-fns';
+import { format as formatDate, parse as parseDate, isValid } from 'date-fns';
 export const getFormattedDate = (inputDate: Date | string = ''): string => {
   // Dates must be formatted YYYY-MM-DD for patternfly date picker.
   // They are coming back inconsistently from the backend,
   // so this function checks to see if the date needs to be formatted,
   // then formats the date appropriately
-  if (!inputDate) {
+  if (!inputDate || (inputDate instanceof Date && !isValid(inputDate))) {
     return;
   }
   if (inputDate instanceof Date) {

src/components/engagement_form_fields/engagement_start_end_date.tsx

@@ -33,6 +33,12 @@ export function EngagementStartEndDateFormField(
     ] as number) ?? 0;
 
   const getRetirementDate = (): string => {
+    if (
+      !props.engagement.end_date ||
+      !(props.engagement?.end_date instanceof Date)
+    ) {
+      return undefined;
+    }
     if (props.engagement?.archive_date || retirementDateChanged) {
       return getFormattedDate(props.engagement?.archive_date);
     } else if (props.engagement?.end_date) {