Just found the mistake. My regex didn't match zeros and therefore it did not recognize +10 or -10 movements correctly. Sorry, my bad.

Manually executing those changes lead me to the expected value, not your submitted answer.

Note that your submitted answer is [ 'l', 'e', 'Q', 'I', 'z', 'f', 'P', 'O', 'm', 'h', 'U', 'w', 'E' ] and the expected value is [ 'h', 'e', 'Q', 'I', 'z', 'f', 'P', 'O', 'm', 'U', 'l', 'w', 'E' ], not the other way around.

You might be interpreting +n as moving right instead of left, but I have not checked that. Otherwise, I really don't know, but that test is definitely correct.

I have already reset, there still to many tests failing

Here is another test result:

expected [ 'l', 'e', 'Q', 'I', 'z', 'f', 'P', 'O', 'm', 'h', 'U', 'w', 'E' ] to deeply equal [ 'h', 'e', 'Q', 'I', 'z', 'f', 'P', 'O', 'm', 'U', 'l', 'w', 'E' ]

leaderboardSort(["l","z","f","e","O","m","P","I","U","h","w","E","Q"], ["Q +3","Q +5","I +2","h +10","f -4","P +1","z -5","f -1","O +1","Q +0","l -10","O -5","l +1"])

There is nothing smaller sorry

Make sure you have the correct tests ( reset ), and can you post a smaller counterexample?

does not work for me. I carefully went through all changes by hand and I know my algo spits out the correct changes to the board. Test this my result is:

assert.deepEqual(leaderboardSort(["ivy","uQV","YiJ","pBO","uhU","RHK","zJx","bhQ","pcj","LbZ","QJv","usq","uZi","KFM"], ["QJv +9","uZi +8","pcj +8","usq +7","pcj -11","usq +3","uQV -3","bhQ +7","uhU +3","LbZ +8","LbZ -10","pcj +3","ivy -9","KFM +9"]), [ 'usq',
'QJv',
'bhQ',
'KFM',
'YiJ',
'uhU',
'uZi',
'pBO',
'uQV',
'pcj',
'ivy',
'RHK',
'zJx',
'LbZ' ]);

Result : [ 'pcj',
'QJv',
'usq',
'bhQ',
'KFM',
'LbZ',
'YiJ',
'uhU',
'uZi',
'uQV',
'pBO',
'ivy',
'RHK',
'zJx' ]

ok

It is now, but it was ok immediately after approval last time.

Check again tomorrow.

Is it ok now?

It looks like the JS tests got rolled back to the first translation version. That suffered from major issues, and had been fixed. But it's unfixed now.

You're probably relying on undefined behaviour.