The move towards rich frontend applications is a fact of life at the moment. There are lots of ad-hoc apps out there that have 1000s of lines of js in a single file. These guys put the work in to fix that - then they kindly spent their time writing it up so we could profit from what they learnt.

Granted 8.5k lines is a lot - but I'll bet there are more shocking projects out there than that. (I've seen much worse than that on the server side)