```ts
export function truncate(text: string, limit: number): string {
  if (typeof limit !== 'number' || limit < 3) {
    throw new Error('Limit must be a non-negative integer of at least 3');
  }
  
  if (text.length <= limit) {
    return text;
  }
  
  return text.slice(0, limit - 4).padEnd(limit, '...');
}
```