Remember, this is Javascript, so it's not an unreasonable reading of the license that merely serving it counts as "Conveying" it, per the terms of the AGPL. To wit:
To "convey" a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user through a computer network, with no transfer of a copy, is not conveying.
Thats a question regarding when a combined work is created (not about code communicating over a network...).
Its not that difficult question to look into. Imagine that I would "convey" a photo by using img tags and "link" proprietary photos inside advertisement banners. Would the banner count as a combined work, or as two separate and disconnected works?
I would lean towards the single combined work, because thats how I think a non-technical judge would look at it.