sbt-grunt integration for Play Framework apps

Build.scala

import play.PlayRunHook
import sbt._
import Keys._
import play.Play.autoImport._
import play.PlayImport.PlayKeys.playRunHooks
import java.net.InetSocketAddress

object ApplicationBuild extends Build {

  import Grunt.GruntTasks

  val appName = ""
  val appVersion = ""
  val projectScalaVersion = "2.11.1"

  scalaVersion := projectScalaVersion

  // Dependencies
  val appDependencies = Seq(
    // Add your project dependencies here,
  )

  // Grunt task to run on "sbt run"
  val gruntDefault = TaskKey[Unit]("grunt default")

  val gruntSettings = gruntDefault := GruntTasks.`grunt:default`

  // Project configuration
  val main = Project(appName, file(".")).enablePlugins(play.PlayScala)
      .settings(gruntSettings).settings(
    version := appVersion,
    scalaVersion := projectScalaVersion,
    libraryDependencies ++= appDependencies,
    // Run "grunt watch" on "sbt run"
    playRunHooks <+= baseDirectory.map(base => Grunt(base)),
    compile in Compile <<= (compile in Compile).dependsOn(gruntDefault),
    // commands to sbt interactive shell
    commands ++= GruntTasks.all,
    commands ++= CustomTasks.all,
    // no docs please
    sources in (Compile, doc) := Seq.empty,
    publishArtifact in (Compile, packageDoc) := false
  )

}


object Grunt {
  def apply(base: File): PlayRunHook = {

    object GruntProcess extends PlayRunHook {

      var process: Option[Process] = None

      override def beforeStarted(): Unit = {
        Process("grunt default", base).run
      }

      override def afterStarted(addr: InetSocketAddress): Unit = {
        process = Some(Process("grunt watch", base).run)
      }

      override def afterStopped(): Unit = {
        process.map(p => p.destroy())
        process = None
      }
    }

    GruntProcess
  }

  object GruntTasks {

    def grunt: Command = Command.args("grunt", "<task>") { (state, args) =>
      ("grunt " + args.mkString(" ")).!
      state
    }

    def `grunt:watch`: Command = Command.command("grunt-watch") { state =>
      "grunt watch".!
      state
    }

    def `grunt:default`: Command = Command.command("grunt-default") { state =>
      "grunt".!
      state
    }

    def all: Seq[Command] = Seq(grunt, `grunt:watch`, `grunt:default`)
  }
}

object CustomTasks {
  def npm: Command = Command.args("npm", "<task>") { (state, args) =>
    ("npm " + args.mkString(" ")).!
    state
  }

  def yo: Command = Command.args("yo", "<task>") { (state, args) =>
    ("yo " + args.mkString(" ")).!
    state
  }

  def bower: Command = Command.args("bower", "<task>") { (state, args) =>
    ("bower " + args.mkString(" ")).!
    state
  }

  def all: Seq[Command] = Seq(npm, yo, bower)
}