Add very basic Kotlin/JS support: ability to compile the binary

docs/modules/ROOT/pages/kotlinlib/web-examples.adoc

@@ -12,7 +12,12 @@ It covers setting up a basic backend server with a variety of server frameworks
 == Ktor Hello World App
 
 include::partial$example/kotlinlib/web/1-hello-ktor.adoc[]
+
 == Ktor TodoMvc App
 
 include::partial$example/kotlinlib/web/2-todo-ktor.adoc[]
 
+== (Work In Progress) Simple KotlinJS Module
+
+include::partial$example/kotlinlib/web/3-hello-kotlinjs.adoc[]
+

example/kotlinlib/web/3-hello-kotlinjs/build.mill

@@ -0,0 +1,43 @@
+// KotlinJS support on Mill is still Work In Progress (WIP). As of time of writing it
+// does not support third-party dependencies, Kotlin 2.x with KMP KLIB files, Node.js/Webpack
+// test runners and reporting, etc.
+//
+// The example below demonstrates only the minimal compilation, running, and testing of a single KotlinJS
+// module. For more details in fully developing KotlinJS support, see the following ticket:
+//
+// * https://github.com/com-lihaoyi/mill/issues/3611
+
+package build
+import mill._, kotlinlib._, kotlinlib.js._
+
+object foo extends KotlinJSModule {
+  def moduleKind = ModuleKind.ESModule
+  def kotlinVersion = "1.9.25"
+  def kotlinJSRunTarget = Some(RunTarget.Node)
+  object test extends KotlinJSModule with KotlinJSKotlinXTests
+}
+
+
+/** Usage
+
+> mill foo.run
+Compiling 1 Kotlin sources to .../out/foo/compile.dest/classes...
+Hello, world
+stringifiedJsObject: ["hello","world","!"]
+
+> mill foo.test # Test is incorrect, `foo.test`` fails
+Compiling 1 Kotlin sources to .../out/foo/test/compile.dest/classes...
+Linking IR to .../out/foo/test/linkBinary.dest/binaries
+produce executable: .../out/foo/test/linkBinary.dest/binaries
+...
+error: AssertionError: Expected <Hello, world>, actual <Not hello, world>.
+
+> cat out/foo/test/linkBinary.dest/binaries/test.js # Generated javascript on disk
+...assertEquals_0(getString(), 'Not hello, world');...
+...
+
+> sed -i.bak 's/Not hello, world/Hello, world/g' foo/test/src/foo/HelloTests.kt
+
+> mill foo.test # passes after fixing test
+
+*/

example/kotlinlib/web/3-hello-kotlinjs/foo/src/foo/Hello.kt

@@ -0,0 +1,11 @@
+package foo
+
+fun getString() = "Hello, world"
+
+fun main() {
+    println(getString())
+
+    val parsedJsonStr: dynamic = JSON.parse("""{"helloworld": ["hello", "world", "!"]}""")
+    val stringifiedJsObject = JSON.stringify(parsedJsonStr.helloworld)
+    println("stringifiedJsObject: " + stringifiedJsObject)
+}

example/kotlinlib/web/3-hello-kotlinjs/foo/test/src/foo/HelloTests.kt

@@ -0,0 +1,13 @@
+package foo
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class HelloTests {
+
+    @Test
+    fun failure() {
+        assertEquals(getString(), "Not hello, world")
+    }
+}
+

kotlinlib/src/mill/kotlinlib/KotlinModule.scala

@@ -7,7 +7,7 @@ package kotlinlib
 
 import mill.api.{Loose, PathRef, Result}
 import mill.define.{Command, ModuleRef, Task}
-import mill.kotlinlib.worker.api.KotlinWorker
+import mill.kotlinlib.worker.api.{KotlinWorker, KotlinWorkerTarget}
 import mill.scalalib.api.{CompilationResult, ZincWorkerApi}
 import mill.scalalib.{JavaModule, Lib, ZincWorkerModule}
 import mill.util.Jvm
@@ -92,11 +92,6 @@ trait KotlinModule extends JavaModule { outer =>
    */
   def kotlinCompilerIvyDeps: T[Agg[Dep]] = Task {
     Agg(ivy"org.jetbrains.kotlin:kotlin-compiler:${kotlinCompilerVersion()}") ++
-//      (
-//        if (Seq("1.0.", "1.1.", "1.2").exists(prefix => kotlinVersion().startsWith(prefix)))
-//          Agg(ivy"org.jetbrains.kotlin:kotlin-runtime:${kotlinCompilerVersion()}")
-//        else Seq()
-//      ) ++
       (
         if (
           !Seq("1.0.", "1.1.", "1.2.0", "1.2.1", "1.2.2", "1.2.3", "1.2.4").exists(prefix =>
@@ -106,15 +101,8 @@ trait KotlinModule extends JavaModule { outer =>
           Agg(ivy"org.jetbrains.kotlin:kotlin-scripting-compiler:${kotlinCompilerVersion()}")
         else Seq()
       )
-//    ivy"org.jetbrains.kotlin:kotlin-scripting-compiler-impl:${kotlinCompilerVersion()}",
-//    ivy"org.jetbrains.kotlin:kotlin-scripting-common:${kotlinCompilerVersion()}",
   }
 
-//  @Deprecated("Use kotlinWorkerTask instead, as this does not need to be cached as Worker")
-//  def kotlinWorker: Worker[KotlinWorker] = Task.Worker {
-//    kotlinWorkerTask()
-//  }
-
   def kotlinWorkerTask: Task[KotlinWorker] = Task.Anon {
     kotlinWorkerRef().kotlinWorkerManager().get(kotlinCompilerClasspath())
   }
@@ -264,7 +252,7 @@ trait KotlinModule extends JavaModule { outer =>
           (kotlinSourceFiles ++ javaSourceFiles).map(_.toIO.getAbsolutePath())
         ).flatten
 
-        val workerResult = kotlinWorkerTask().compile(compilerArgs: _*)
+        val workerResult = kotlinWorkerTask().compile(KotlinWorkerTarget.Jvm, compilerArgs: _*)
 
         val analysisFile = dest / "kotlin.analysis.dummy"
         os.write(target = analysisFile, data = "", createFolders = true)