Describe the Rails Asset Pipeline and how it handles assets (such as JavaScript and CSS files)

Rails 3.1 introduced the Asset Pipeline, a way to organize and process front-end assets. It provides an import/require mechanism (to load dependent files) that provides many features. While the Asset Pipeline does have its rough edges, it does solve and provide many of the modern best practices in serving these files under HTTP 1.1. Most significantly, the Asset Pipeline will:

• Collect, concatenate, and minify all assets of each type into one big file
• Version files using fingerprinting to bust old versions of the file in browser caches

The Asset Pipeline automatically brings with it Rails’ selection of Coffeescript as its JavaScript pre-processed / transpiled language of choice and SASS as its CSS transpiled language. However, being an extensible framework, it does allow for additional transpiled languages or additional file sources. For example, Rails Assets brings the power of Bower to your Rails apps, allowing you to manage third-party JavaScript and CSS assets very easily.