flattenEntries function presentation

function flattenEntries(
  entries: SelectEntry[],
): Array<SelectOption & { groupLabel?: string }> {
  const result: Array<SelectOption & { groupLabel?: string }> = [];
  for (const entry of entries) {
    if (isGroup(entry)) {
      for (const o of entry.options) {
        result.push({ ...o, groupLabel: entry.groupLabel });
      }
    } else {
      result.push(entry);
    }
  }
  return result;
}