This helps with front end caches and CDNs as well. The main trick is upload all of the non-html changes before the html changes, so that no file is referenced

This helps with front end caches and CDNs as well. The main trick is upload all of the non-html changes before the html changes, so that no file is referenced before it exists. If you want to make the app as complex as possible you do a depth first search for upload. But if you value your sanity you relax the problem and have assets-first in your app.