In Ruby on Rails how can I combine multiple Javascript files at runtime?

Question

I am building a Facebook App which is heavy on Javascript. For this I have multiple Javascript files. Since in Facebook development, the page is served over a tunnel, there is excessive latency added while requesting multiple javascript files. Is it possible to combine the contents of multiple javascript files at runtime? Having multiple files makes it easy to develop, and hence I am avoiding having to combine it while development itself.

Answer 1

Better than combining at runtime, have a look at Frizione. It's a framework that will allow you to combine your javascript files at deploy time, and compress them. So you get to save all around. It throws in doc generation and JSLint checking as well, but that's just an added bonus.

Answer 2

You can pass a :cache option to the javascript_include_tag which will combine the files into one:

<%= javascript_include_tag :all, :cache => true %>

Note that this depends on ActionController::Base.perform_caching being set to true, which it is by default for the Rails production environment.

• See http://api.rubyonrails.org/classes/ActionView/Helpers/AssetTagHelper.html#M001493

Answer 3

I've used the asset_packager gem to do this in my applications.

It will combine and minimize your javascript (and CSS) files for production and adds some view helpers that make it very easy to use. There's a rake command that you run to generate the packaged files if the originals have changed.

Answer 4

Jammit is a good catch too, to combile js and css files.

http://documentcloud.github.com/jammit/