Django : Is it a good idea to generate JS dynamically?

Question

When I write my JS files for a Django project, of course I do some AJAX calls, and for the moment the urls for those calls are hard-coded (which is very ugly).

I was thi

Answer 1

Dynamically generating Javascript on your server can be a tremendously powerful tool and I've experienced both it's upside and downside in my projects.

In general you want to keep as much as possible static to minimize the work to be done on every request. This includes having the browser cache as much as possible, which might become a problem in your case.

What I usually do is to have a block in the header in my base template. In templates that need to do custom javascript that is only known at runtime (customization based on logged in user, for example), I add it to the block. Here I can dynamically generate javascript that I know won't be cached so I can make some assumptions. The downside is more complexity.

If what you need are just pointing to urls, or have some simple configuration, etc, then I would suggest creating a view that will return a Javascript file with these settings. You can set the correct headers(Etag, Cache-Control, etc) so the browser will cache the file for some reasonable time. When you upgrade your code, make sure the Etag will change.

In the code that needs to use the configuration, you need to always check that the variable you are looking for is actually defined otherwise you will run into problems that are hard to debug when for some reason the configuration javascript is not loaded correctly.