Using jsdom.jsdom() in express.js I create a document with some 'base' layout markup and attach a few client side libraries such as jQuery to its window. 

It would be nice to only have to do this setup once.

The problem is that the DOM of the window's document will change depending on the requested url. Is there a way for each request to start from the same cached window object and enhance it or does it have to be setup from scratch on every request?