method Promise.catch Private Promise.catch<TResult = never>(onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null): Promise<T | TResult> Attaches a callback for only the rejection of the Promise. Type Parameters TResult = never Parameters optional onrejected: ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null The callback to execute when the Promise is rejected. Return Type Promise<T | TResult> A Promise for the completion of the callback.