How can I create a simple scala.js cross project with client, server and api modules? - intellij-idea

Question

I would like to create a very simple Scala.js application with three modules under a project root like this:
project
-server
-client
-api
This is a cross project because I would like the source in the api module to be compiled by both Scala and Scala.js. I understand that this might nescessitate the need for two api modules (which share the same source code), jvm type and js type.
Source in the server module should only be compiled by Scala and source in the client module should only be compiled by Scala.js. The server module needs to depend on the api module (jvm type) whereas the client module needs to depend on the api module (js type).
Could someone please post the most basic build.sbt that shows how this can be achieved?
EDIT:
It looks like this is the way to do it:
lazy val commonSettings = Seq(
scalaVersion := "2.12.1"
)
lazy val projectRoot = project.in(file(".")).
aggregate(client, server).
settings(
name := "projectRoot"
)
lazy val server = project.in(file("server")).
settings(
commonSettings
).
dependsOn(apiJvm)
lazy val client = project.in(file("client")).
settings(
commonSettings
).
enablePlugins(ScalaJSPlugin).
dependsOn(apiJs)
lazy val api = crossProject.in(file(".")).
settings(
commonSettings
).
jvmSettings(
// Add JVM-specific settings here
).
jsSettings(
// Add JS-specific settings here
)
lazy val apiJvm = api.jvm.in(file("apiJVM"))
lazy val apiJs = api.js.in(file("apiJS"))
The only problem with this is the shared source goes into a folder called shared with a different module name in IntelliJ. It's a shame it isn't in an api folder with a module name of api. Presumably I shouldn't put any code in the apiJS and apiJVM modules that get created? They are only there to be used as dependencies?