Does the asset pipeline (RoR 3.1) waste cycles?

With the Ruby on Rails asset pipeline in RoR 3.1, it’s unclear if the .coffee and the //= require files get processed only once or with each asset request.

For example, I have a file that looks like this:

//= require source/main.js.coffee
//= require source/second.js.coffee
//= require source/third.js.coffee

Ideally, the server would compile these to js ONCE, then bundle them, then create a static file. Otherwise it’s going to be wasting cycles repeating effort.

Can someone clarify what happens?

Thanks,
Jeff

In a development environment it recompiles the assets on every
request. When in production it does it once and adds a hash to the
filename for caching.

Dieter Lunn
http://ubiety.ca