JavaScript concatenation and minification

[hmans]

So, yeah, we need this stuff. Forcing people to just set up Webpack is not an option; this should be done by Flutterby out of the box.

Ideally, this would be implemented as a filter extension. For example, if we establish packager as the filter extension, your main JavaScript file could be /js/app.js.packager; this file could then load JavaScript files from another (private) directory, bundle them, and export them as /js/app.js.

Here's a quick todo list:

• investigate if any part of Sprockets may be reused for this
• find good concatenation/minification/etc. gems
• figure out a DSL (or any other configuration syntax) for .packager files

Potentially relevant gems:

• https://github.com/lautis/uglifier
• https://github.com/jcoglan/packr (not updated since 2013?)

[hmans]

Got a naive implementation working here... \o/