Hi, I'm sigalor, the original creator of the project.
Actually, now I also regret using Python in addition to NodeJS. When I started all of this back in November, I originally chose Python, because it's, well, "quick and dirty". Especially trimming arrays and working with byte strings requires a lot more code in JS than it does in Python.
I even wrote a reimplementation of the decryption routines in JavaScript, but it's not working entirely (the HMAC authentication of received messages fails, though login works).