Merge pull request #936 from Eastern-Research-Group/bugfix/664_restor…

…e-characterstics-select-header

HMW-664 Fixed array access bug in characteristics select menu

app/client/src/components/shared/PaginatedSelect.tsx

@@ -31,9 +31,9 @@ export function PaginatedSelect(props: Props) {
   const { options: optionsOrGroups, styles, ...rest } = props;
 
   const options = useMemo(() => {
-    return optionsOrGroups.flatMap((groupOrOption) => {
-      if ('options' in groupOrOption) return groupOrOption.options;
-      return groupOrOption;
+    return optionsOrGroups.flatMap((optionOrGroup) => {
+      if ('options' in optionOrGroup) return optionOrGroup.options;
+      return optionOrGroup;
     });
   }, [optionsOrGroups]);
 
@@ -69,7 +69,9 @@ export function PaginatedSelect(props: Props) {
 
   const optionsOrGroupsPage = useMemo(() => {
     const page = filteredOptions.slice(startIndex, startIndex + PAGE_SIZE * 2);
-    return 'options' in optionsOrGroups
+    // A group is only used in one place, so we can get away with only checking the first item.
+    const optionOrGroup = optionsOrGroups[0];
+    return optionOrGroup && 'options' in optionOrGroup
       ? [{ label: 'Group', options: page }]
       : page;
   }, [filteredOptions, optionsOrGroups, startIndex]);