```typescript
/**
 * 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' || limit < 3) {
    throw new Error('limit must be a positive integer of at least 3');
  }
  return text.length <= limit || text === ""
    ? text
    : text.slice(0, limit - 4) + "...";
}
```