```ts
/** The text, cut to limit characters with an ellipsis when it is longer. */
export function truncate(text: string, limit: number): string {
  if (typeof limit !== 'number' || !Number.isInteger(limit) || limit < 3) {
    throw new Error('limit must be a positive integer');
  }
  if (text.length <= limit) {
    return text;
  } else {
    return text.slice(0, limit - 2) + "...";
  }
}
```