interface Promise Private Represents the completion of an asynchronous operation Type Parameters T Methods then<TResult1 = T,TResult2 = never,>(onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | undefined | null,onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | undefined | null,): Promise<TResult1 | TResult2> Attaches callbacks for the resolution and/or rejection of the 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.