Without the input value we can't know if your're right or wrong, probably wrong tho:

JavaScript Completions 9105

Take a look at some failed test:

Testing for 80352
It should work for random inputs too: expected 80532 to equal 80523

You can see that your function returned 80532 and the next bigger number with the digits of 80352 is 80523.

Why am i getting error
expected 52398665 to equal 52398566? That doesn't make sense, because 52398566 < 52398665 and we are looking for next bigger, not smaller. Meanwhile my code returns 52938665 which seems like right answer.

No problem, you could try not using sort at all.

I don't see how i can change code to make it work, so i guess i'll just drop this challenge and move on. Thanks for answer

Sort wasn't stable until recent Node's versions, so, either you find a way to make your sort stable or wait for this kata to have newer versions enabled.

You can visualize how it behaves with an older version here: https://pythontutor.com/javascript.html#mode=edit

No one can help you without your code. Read that link about how to post it using markdown formatting.