I console.logged o.split(d) just to see what I get. It gave me [ '0', '49', '6253649648', '', '00' ] for input (10, 1). Someone plz explain why and how do we get that '' value as the second last element ? I think that must be the reason he/she have applied .length - 1 to the solution and not just .length. Correct me if I'm wrong and need a proper explanation. But otherwise an excellent solution.

Could not have imagined split to be used like this.

Such a clever solution!

clever work