Create basic ScalaJS project and serve it from the server

3 files changed, 49 insertions, 3 deletions

diff --git a/build.sc b/build.sc
index 2a544bc..10354e9 100644
--- a/build.sc
+++ b/build.sc
@@ -1,4 +1,4 @@
-import mill._, scalalib._
+import mill._, scalalib._, scalajslib._
 
 object server extends ScalaModule {
   def scalaVersion = "2.13.1"
@@ -10,4 +10,27 @@ object server extends ScalaModule {
     ivy"org.xerial:sqlite-jdbc:3.28.0" // actual database driver, note the single ':'
   )
 
+  // This includes the resulting javascript file so that it can be served
+  // as a classpath resource and is packaged in the final jar.
+  def localClasspath = T {
+    super.localClasspath() ++ List(webapp.asAsset())
+  }
+
+}
+
+object webapp extends ScalaJSModule {
+  def scalaVersion = "2.13.1"
+  def scalaJSVersion = "0.6.31" // https://www.scala-js.org/
+
+  def ivyDeps = Agg(
+    ivy"org.scala-js::scalajs-dom::0.9.7" // http://scala-js.github.io/scala-js-dom/
+  )
+
+  // friendlier name than the default 'out.js'
+  def asAsset = T {
+    val out = T.ctx().dest / "assets" / "app.js"
+    os.copy(fastOpt().path, out, createFolders = true)
+    PathRef(T.ctx().dest)
+  }
+
 }
diff --git a/server/src/Templates.scala b/server/src/Templates.scala
index a512c49..3abb09e 100644
--- a/server/src/Templates.scala
+++ b/server/src/Templates.scala
@@ -50,10 +50,20 @@ object Templates {
       meta(
         name := "viewport",
         content := "width=device-width, initial-scale=1, shrink-to-fit=no"
-      )
+      ),
+      script(`type` := "text/javascript", src := "/assets/app.js")
     ),
     body(
-      conversation(messages) 
+      conversation(messages),
+      script(`type` := "text/javascript")(
+        raw(
+          """|document.addEventListener("DOMContentLoaded", function(event) {
+             |  console.info("Starting ScalaJS application...")
+             |  Main.func() // run ScalaJS application
+             |})
+             |""".stripMargin
+        )
+      )
     )
   )
 
diff --git a/webapp/src/Main.scala b/webapp/src/Main.scala
new file mode 100644
index 0000000..5aa2f2b
--- /dev/null
+++ b/webapp/src/Main.scala
@@ -0,0 +1,13 @@
+
+import org.scalajs.dom
+import scalajs.js.annotation
+
+@annotation.JSExportTopLevel("Main")
+object Main {
+
+  @annotation.JSExport
+  def func() = {
+    dom.console.log("hello from ScalaJS!")
+  }
+
+}