sbt-web plugin for concatenating files together, using the sbt-web asset pipeline.

Add the plugin to your project/plugins.sbt:

addSbtPlugin("com.github.sbt" % "sbt-concat" % "1.0.0")

Enable the sbt-web plugin for your project:

lazy val root = (project in file(".")).enablePlugins(SbtWeb)

Add the concat task to your asset pipeline in your build.sbt:

pipelineStages := Seq(concat)

Below is an example of specifying concat groups within your build.sbt file. You can use PathFinder objects or a Seq[String] to specify the files to concatenate together.

Concat.groups := Seq(
  "style-group.css" -> group(Seq("css/style1.css", "css/style2.css")),
  "script-group.js" -> group(Seq("js/script1.js", "js/script2.js")),
  "style-group2.css" -> group((sourceDirectory.value / "assets" / "style") * "*.css")
)

Note that with a PathFinder, you will need to take care to ensure that the files it selects will be concatenated in the order that you desire.

To match entries in Seq[String] in group PathMapping is used. Only relative paths up to one level deep are guaranteed match.

This will produce three files with concatenated contents:

style-group.css

/** css/style1.css **/
body { color: #000; }
/** css/style2.css **/
#main { background-color: #fff; }

script-group.js

/** js/script1.js **/
function onDomReady(){ ... }
/** js/script2.js **/
$(onDomReady);

style-group2.css

/** assets/style/main.css **/
body { font-weight: bold; }
/** assets/style/base.css **/
section { font-size: 15em; }

These will reside under the asset build directory in the base target directory by default. You can change the name of this directory using the Concat.parentDir SettingKey.

This code is licensed under the MIT License.