Your code skips values, that's why it fails. Don't mutate the array while you iterate over it or do it but in another way.

It isn't, you're probably misreading the error message and that's what your function wrongly returned, not the expected value:

expected        [ 9, +0, 9, 1, 2, 1, 1, 3, 1, 9, +0, +0, 9, +0, +0, +0, +0, +0, +0, +0 ] // this is your answer
to deeply equal [ 9, 9, 1, 2, 1, 1, 3, 1, 9, 9, +0, +0, +0, +0, +0, +0, +0, +0, +0, +0 ] // this is the expected result

JavaScript Completions 55050

ok guys I see a lot of controversy and kind of I'm starting to feel a bit frustrated with this kata.
pls someone explain to me this. since when this is correct test result ?
[ 9, +0, 9, 1, 2, 1, 1, 3, 1, 9, +0, +0, 9, +0, +0, +0, +0, +0, +0, +0 ]