Attaches callbacks for the resolution and/or rejection of the Promise.
method
$.ShellPromise.then
onrejected?: null | (reason: any) => TResult2 | PromiseLike<TResult2>
): Promise<TResult1 | TResult2>;
@param onfulfilled
The callback to execute when the Promise is resolved.
@param onrejected
The callback to execute when the Promise is rejected.
@returns
A Promise for the completion of which ever callback is executed.