RRule: move filtering of empty values to inside the widget.

src/components/EventEdit.tsx

@@ -220,16 +220,7 @@ class EventEdit extends React.PureComponent<PropsType> {
       }
     }
     if (this.state.rrule) {
-      const rruleData: ICAL.RecurData = {};
+      event.component.updatePropertyWithValue('rrule', new ICAL.Recur(this.state.rrule!));
-      for (const key of Object.keys(this.state.rrule)) {
-        const value = this.state.rrule[key];
-        if ((value === undefined) || (value?.length === 0)) {
-          continue;
-        }
-
-        rruleData[key] = value;
-      }
-      event.component.updatePropertyWithValue('rrule', new ICAL.Recur(rruleData));
     }
 
     event.component.updatePropertyWithValue('last-modified', ICAL.Time.now());

src/widgets/RRule.tsx

@@ -80,7 +80,15 @@ interface PropsType {
 export default function RRule(props: PropsType) {
   const options = props.rrule;
   function updateRule(newOptions: Partial<RRuleOptions>): void {
-    const updatedOptions = { ...options, ...newOptions };
+    const updatedOptions: RRuleOptions = { ...options, ...newOptions };
+
+    for (const key of Object.keys(updatedOptions)) {
+      const value = updatedOptions[key];
+      if ((value === undefined) || (value?.length === 0)) {
+        delete updatedOptions[key];
+        continue;
+      }
+    }
     props.onChange(updatedOptions);
   }
   function getEnds(): Ends {