I think actually the trick way has the some time complexity with the simple length way.
However, it's a clever solution.

brilliant

awesome kata, it help me a lot on understanding monad.

Found function defined inside function is really a sharp razor when dealing with complicate logic like such kata.
Anyone else have the same feeling?

so clever, my solution use array with order 1 - 1000. But simply ordering from 1000 to 1, simplify so much thing.

very elegant code, impressive

I learned a lot about reduce from the famous paper why functional programming matters. It's really a awesome paper.
The reduce in js and this kata is somehow not exactly the reduce explained in the paper.

clever!!!