scalasbtasset-pipelinescala.jsfinch

Serving Scala.js assets

I've started new project with Finch and Scala.js, where backend and frontend need to share some code.

And I'm concerned about a good way to serve JS produced by fastOptJS by Finch. Currently, I'm using custom SBT task which copies files from js/target/scala-2.11/*.js to jvm/src/main/resources. But I wondering if there's a better way to do it.

I saw awesome SPA tutorial, which uses sbt-play-scalajs plugin, but It seems applicable only for Play.

Solution

  • One approach which I've used successfully involves 3 sbt projects and an additional folder at the root for static content:

    .
├── build.sbt
├── client
├── server
├── shared
└── static

    In the build.sbt, you would then use something like the following:

    lazy val sharedSettings = Seq(
  // File changes in `/static` should never trigger new compilation
  watchSources := watchSources.value.filterNot(_.getPath.contains("static")))

lazy val server = project
  .settings(sharedSettings: _*)
  // Adds `/static` to the server resources
  .settings(unmanagedResourceDirectories in Compile += baseDirectory.value / ".." / "static")

lazy val client = project
  .enablePlugins(ScalaJSPlugin)
  .settings(sharedSettings: _*)
  // Changes Scala.js target folder to "/static/content/target"
  .settings(Seq(fullOptJS, fastOptJS, packageJSDependencies, packageScalaJSLauncher, packageMinifiedJSDependencies)
    .map(task => crossTarget in (Compile, task) := file("static/content/target")))

    All you assets can be accessed as standard resources, then will also get packaged into your fat jar if you use something like sbt-assembly.