Just from looking at the list of libraries/frameworks/tech used, it seems like it was over-engineered. It was probably a fun project to work on, or maybe it was a good learning experience for the developer, but it seems like it's a wee bit too over-complicated. If someone wanted to release something like this to actual customers then I don't think you'd want to make it like that.

This is coming from someone who started out in the front-end with JS and SPAs. Why add in the responsiveness (and overhead) of a SPA when your users won't really notice the difference?