/** App-extension columns a domain aggregate carries through untouched. */
export type CustomFields = Readonly<Record<string, unknown>>;

export function mergeCustomFields(current: CustomFields, patch: CustomFields | undefined) {
  if (!patch) {
    return current;
  }
  const merged: Record<string, unknown> = { ...current };
  for (const [key, value] of Object.entries(patch)) {
    if (value !== undefined) {
      merged[key] = value;
    }
  }
  return merged;
}