What was most important to me was to make sure I didn’t burn out and get bored. It was important to get to a fun, captivating project asap.
One of the best intro to inner workings of JS : https://www.youtube.com/watch?v=-o8hhJPK0m0&list=PLAwxTw4SYa...
sadly udacity is hell bent on removing all quality content off their website so get it while it's on youtube.
I've also found reading the source for libraries you use and stepping through with a debugger is really the best way to understand them. This is probably how most people learn their in house code at work. Just treat the whole stack like in house code (within reason). And reading code is also a fabulous skill to hone.
But university… we were all noobs back then :D