Organizing large scale javascript web app

I'm working on a big javascript web app. (which is mostly a web game)

Currently the code is written using only jQuery and the Module pattern.

The app is growing big and it gets harder and harder to maintain due to 2 reasons:

1. Separating the code into different files forces me to add a ton of script tags on each html page of the app. I'm looking into requireJS to solve that, is there another recommended solution?
2. Intellisense is having a hard time connecting different files and most of the time doesn't recognize objects that are defined in other files. How can it be fixed? I'm using VS Code.

Thank you!