```ts
/**
 * Truncate a string to the given limit, adding an ellipsis (`...`) when necessary.
 */
export function truncate(text: string, limit: number): string {
  if (!Number.isInteger(limit) || limit < 3) {
    throw new Error('limit must be an integer of at least 3');
  }
  if (text.length <= limit) {
    return text;
  }
  const prefixLength = limit - 3;
  return text.slice(0, prefix