Optional
onfulfilled: null | ((value) => TResult1 | PromiseLike<TResult1> | FuturableLike<TResult1>)The callback to execute when the Futurable is resolved.
Optional
onrejected: null | ((reason) => TResult2 | PromiseLike<TResult2> | FuturableLike<TResult2>)The callback to execute when the Futurable is rejected.
A Futurable for the completion of which ever callback is executed.
Attaches callbacks for the resolution and/or rejection of the Futurable.