fix: props that have default values cannot be undefined

Author: laug

src/index.tsx

@@ -586,13 +586,8 @@ export default class DatePicker extends Component<
       lastPreSelectChange: PRESELECT_CHANGE_VIA_INPUT,
     });
 
-    const {
-      dateFormat = DatePicker.defaultProps.dateFormat,
-      strictParsing = DatePicker.defaultProps.strictParsing,
-      selectsRange,
-      startDate,
-      endDate,
-    } = this.props;
+    const { dateFormat, strictParsing, selectsRange, startDate, endDate } =
+      this.props;
 
     const value =
       event?.target instanceof HTMLInputElement ? event.target.value : "";
@@ -603,15 +598,15 @@ export default class DatePicker extends Component<
         .map((val) => val.trim());
       const startDateNew = parseDate(
         valueStart ?? "",
-        dateFormat,
+        dateFormat!,
         this.props.locale,
-        strictParsing,
+        strictParsing!,
       );
       const endDateNew = parseDate(
         valueEnd ?? "",
-        dateFormat,
+        dateFormat!,
         this.props.locale,
-        strictParsing,
+        strictParsing!,
       );
       const startChanged = startDate?.getTime() !== startDateNew?.getTime();
       const endChanged = endDate?.getTime() !== endDateNew?.getTime();
@@ -632,9 +627,9 @@ export default class DatePicker extends Component<
       // not selectsRange
       const date = parseDate(
         value,
-        dateFormat,
+        dateFormat!,
         this.props.locale,
-        strictParsing,
+        strictParsing!,
         this.props.selected ?? undefined,
       );