For this particular issue, Apple allows apps to dynamically download Javascript and other web tech (in order for web browsers to work), and they explicitly mention that they're not into you pushing big updates:
provided that such scripts and code do not change the primary purpose of
the Application by providing features or functionality that are inconsistent
with the intended and advertised purpose of the Application as submitted
to the App Store.
As always, the App Review Team gets the final say on a case-by-case basis for whether you'll get through or not.