JavaScript dependency management and concatenation: Sprockets

Sprockets is a Ruby library that preprocesses and concatenates JavaScript source files. It takes any number of source files and preprocesses them line-by-line in order to build a single concatenation. Specially formatted lines act as directives to the Sprockets preprocessor, telling it to require the contents of another file or library first or to provide a set of asset files (such as images or stylesheets) to the document root.