Nice

one question. I was looking about the join and best practices. But I have not found any info.

Why is not a best practice the use of join? do you have a link or a little explanation about that, pls :)

I didn't even think of using a map. Was so focused on iterating through the array and working with a string it didn't even occur to me. Tunnel vision.

Very hard for beginner!

"expected [ 1, [ 2, 3 ], …(2) ] to deeply equal [ 1, [ 2, 3 ], …(2) ]"

"expected [ …(5) ] to deeply equal [ …(5) ]"

:)

I essentially did the same code but declaring arrays and variables. This is much smoother !

Great solution! I like how you only need to use the reverse method once, so it makes it faster than the 2nd popular option.

A linting tool will warn you about the use of nested ternary operators. This reduces clarity.

wish i can do same

ok

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The description should be completely rewritten as as of now it's incomprehensible:

• "The tryCode() function is called in loop" - is this the function I'm supposed to implement or call myself?
• "then it is the result array of the confrontation between last proposition and solution" - this statement makes no sense whatsoever.
• "tryCode([1, 0, -1]) // [0, 2, 4] isn't the solution..." - why is there no output? And why is the JavaScript's single-line-comment syntax used in the middle of the text?