```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 < 4) {
    throw new Error("limit must be a non-negative integer of at least 3");
  }
  return text.length <= limit ? text : `${text.slice(0, limit - 4)}...`;
}
```