You know what Jonathan? I think you found a bug, because uniqueScores[mid — 1 > score] really should evaluate to a boolean, which should then return undefined when looking up a boolean in the uniqueScores array. Intuitively, it really feels like the code should be uniqueScores[mid — 1] > score
I changed the code in HackerRank, and some tests passed, and some failed. I tried looking at the failed tests, and of course, they’re crazy long, and not very useful.
I suggest your main takeaway ought to be the algorithm, and you can use the these steps to pseudocode your own solution.
Sorry I couldn’t be much more help!