sbt 0.13.15 override runTask in play project

I'm trying to create a custom runTask for a play project with sbt 0.13.15. I'm wondering if this is possible.

The sbt documentation suggests using fullRunTask to define a custom run task, but I'd really just like to add another task to execute before sbt run (i.e. run depends on this custom task).

Overall goal is to create a task that transpiles some javascript whenever sbt run is invoked.

I honestly cannot find a way to make the current runTask depend on my custom fooTask.

This is what I'm trying:

lazy val playProject = (project in file("somePlayProject"))
    .settings(//some common settings and library deps)
        run in Compile := {
            val jsTranspile: Seq[String] = Seq("bash", "-c", "commands", "to", "transpile")
            jsTranspile !
            (run in Compile).evaluated

Unfortunately, this just runs the normal sbt run for a play project. If I remove the (run in Compile).evaluate command, then the jsTranspile task runs successfully. I'm not sure how to harmonize the two.