0

I have a Scala.js project with an index.html file. Currently I use a structure like in Scala.js example, with two different index.html files for fullOptJS and fastOptJS builds. However I would like to DRY this somehow.

I think it should be possible to generate both index.html and index-fastopt.html from a common source template using a simple Scala code doing the substitution of the variable parts. Perhaps one could achieve this using Generating sources and resources, but I am unsure how.

Suma
  • 33,181
  • 16
  • 123
  • 191

1 Answers1

2

I did a checkout of the scala.js example project and modified it a little bit.

First, edit index.html and replace the following lines:

<script type="text/javascript" src="./target/scala-2.11/example-opt.js"></script>
<script type="text/javascript" src="./target/scala-2.11/example-launcher.js"></script>

with:

<script type="text/javascript" src="{{example.js}}"></script>
<script type="text/javascript" src="example-launcher.js"></script>

Next, add the following lines in build.sbt:

def generateIndexTask(suffix: String) = Def.task {
  val source = baseDirectory.value / "index.html"
  val target = (crossTarget in Compile).value / "index.html"
  val log = streams.value.log
  IO.writeLines(target,
    IO.readLines(source).map {
      line => line.replace("{{example.js}}", s"example-$suffix.js")
    }
  )

  log.info(s"generate with suffix: $suffix")
}

(fastOptJS in Compile) <<= (fastOptJS in Compile).dependsOn(generateIndexTask("fastopt"))
(fullOptJS in Compile) <<= (fullOptJS in Compile).dependsOn(generateIndexTask("opt"))

The generated index.html will be located at the sample place as the generate .js files: ./target/scala-2.11

You should probably adjust the file paths to your own use.

For my own projects, I use another structure with a sbt-web project at the top level to manage all assets and the scala-js code in a sub-project that exports it's code as a webjar. It's more flexible.

Olivier Samyn
  • 1,105
  • 8
  • 13
  • Work fine. The index.html output file name should be probably different for fast/full Opt, though. – Suma May 11 '16 at 11:37
  • 1
    To do this, just replace in the target value: `"index.html"` with `s"index-$suffix.html"`. For my personal taste, I prefer always loading the same file, and let the build system handle the correct generation. – Olivier Samyn May 11 '16 at 12:58