export function makeTestId<T extends string | undefined>(rootId: T, subComponentId: string): T;
export function makeTestId<T extends string | undefined>(
  rootId: T,
  subComponentId: string,
  subComponentModifier: string,
): T;

/**
 * Return string that should be used as testId.
 *
 * Format will be `rootId__subComponentId--subComponentModifier`.
 */
export function makeTestId(
  rootId?: string,
  subComponentId?: string,
  subComponentModifier?: string,
): string | unknown {
  if (!rootId) {
    return undefined;
  }

  let id = `${rootId}__${subComponentId}`;
  if (subComponentModifier !== undefined) {
    id += `--${subComponentModifier}`;
  }

  return id;
}