uglifyOps usage example

[loicdescotte]

Hi,

It would be good to add an example of uglifyOps usage in the README.
The definiton is quite complex (SettingKey[(Seq[(File, String)]) => Seq[(Seq[(File, String)], String)]]) and not sufficient to understand the usage.

Thanks

[dpennell]

You need to supply a function that partitions a standard sbt mapping seq (Seq[(File, String)] into groups or layers. A convenient way to do this is to create a method in e.g. project/Layers.scala:

object Layers {
  def mapToLayers(inMappings: Seq[File, String]): Seq[(Seq[(File, String), String)] = {
   ....
  }
}

and then in build.sbt,

.settings(uglifyOps = Layers.mapToLayers)

The String field that groups mappings is actually a relative path name. So you probably want to use something like "javascript/Layer1.js". This file will contain all files listed for that group concatenated and uglified. It will have a companion file with .map appended to the name.

[marcialca]

I think this example could help you out too:

https://github.com/sbt/sbt-uglify/blob/master/src/sbt-test/sbt-uglify/uglify-concat/build.sbt#L7