```ts
/**
 * The text, cut to limit characters with an ellipsis when it is longer.
 */
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.");
  }
  const truncatedText = text.slice(0, limit);
  return truncatedText.length === limit ? truncatedText : `${truncatedText.slice(0, -2)}...`;
}
```