Right. I was working directly with base array. Now it's ok. Thanks for clarification.

Confirm. Seems like something wrong with random test function for js. Test output:

It should work for random inputs too - Expected: 952, instead got: 146```

My sequence: `[ 9, 1, 5, 42, 146]`

Basic test passed with no errors.

It made me realize that I have no idea on how to debug invisible string characters

I found you can use console.dir() on your result for this case or just test your function in browser's console.