While it was indeed a front end project. I was not _unskilled_ or unfamiliar with JavaScript, and had been working with it since the late 90s. I made this abundantly clear going in. It just had not up to this point been my focus, but I was very excited to grow into the position.
They could have at the very least looked at something they had me spend hours on. Honest to god, if they'd had a single person cast eyes on it for 15 seconds I wouldn't hold this grudge.
I still have the code in a private repo on GitHub and looking at it now it's very clean and with small exception not unlike code I would write today.