[Feature Request] Implement a `keepLastArray` option

[HapLifeMan]

Hello,

Thanks for this awesome library!

I was wondering if it was possible to implement a new option based on keepArray.

My goal is to have a full dot-object but only keeping the last arrays (if this array doesn't have any other nested properties).

It would be super useful and I wish it worked like this at first :)

Or if you don't want to implement this option, could you help me to achieve it?

Thanks a lot!