I really like this idea of filtering out the negative items first!

That's how I did it :D

wow your solution is better than mine

Impressive)

practice more

goood job

Neat! Very clean.

Unrelated: reading your solution made Big O notation make sense to me. :)

Every item in the incoming array is processed twice, first to remove everything that's equal to or greater than zero to a fresh array, and then to sum every element of that new list. Every item is essentially touched twice so it's O squared, but technically maybe it's kind of smaller than that in an ideal case because the reducer only does its work on the resulting, probably smaller, subset of filtered numbers.

Thanks, I know this is sort of unrelated, I just needed to go off for a sec.

for initialitation
valeur a will begin with 0

like my solution hhhhh

I am not splitting hairs, but isn't it regarded as bad practice to omit curly brackets around statements? I vaguely remember having read about it somewhere at MDN though.

very smart sintax