```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" || limit < 3) {
    throw new Error("Limit must be a positive integer of at least 3.");
  }
  if (text.length <= limit) {
    return text;
  }
  const ellipsis = "...";
  const truncatedLength = limit - ellipsis.length;
  return text.slice(0, truncatedLength) + ellipsis;
}
```