This basically means "Give me an array of letters from sorted input array's first item" ;)

You need to wrap those values with brackets [], because what you posted isn't an array. Using "3 dots" on a string returns an array of characters.

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

i don't understand why the three dots (...), return us an array and not something like this :
"paolo","zarate","azorsa","daniel".
i replaced the ...s with those values: "paolo","zarate","azorsa","daniel", to see what is going on, but i gives me an error.

Not now~~

No problem, I revisited my first solution and it mutated the input too ;). Refactored it to make it pure now.

Lol you just edited your comment as the time I write the reply ^^

In French we say "Les grands esprits se rencontrent".

Should be upvoted best practice as it does not mutate the input.

Having issue with the "and" between the last two arguments in javascript. Majority of the random tests seem to omit it completly, therefore kata can't be submitted.

Expected: ''You gave me 5 arguments and they are "152234", "donkey", "false", "seven seven", "lamp-light".'',

instead got: ''You gave me 5 arguments and they are "152234", "donkey", "false", "seven seven" and "lamp-light".''

It seems I have the same issue. Whenever I run the code in my IDE, it works as expected, if its ran on codewars random test, got at least 10 errors or so, though if I copy the random samples to my IDE, they all work just fine...