Add Scala.js cross build

.travis.yml

@@ -12,8 +12,11 @@ env:
     # SONA_PASS
     - secure: "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"
   matrix:
-    - ADOPTOPENJDK=8
-    - ADOPTOPENJDK=11
+    # The empty SCALAJS_VERSION will only compile for the JVM
+    - SCALAJS_VERSION=         ADOPTOPENJDK=8
+    - SCALAJS_VERSION=0.6.28   ADOPTOPENJDK=8
+    - SCALAJS_VERSION=1.0.0-M8 ADOPTOPENJDK=8
+    - SCALAJS_VERSION=         ADOPTOPENJDK=11
 
 before_install:
   # adding $HOME/.sdkman to cache would create an empty directory, which interferes with the initial installation

build.sbt

@@ -1,26 +1,48 @@
+import sbtcrossproject.CrossPlugin.autoImport.{ crossProject, CrossType }
 import ScalaModulePlugin._
 
-scalaModuleSettings
-scalaModuleSettingsJVM
-
-name := "scala-collection-contrib"
-version := "0.1.1-SNAPSHOT"
-
-crossScalaVersions in ThisBuild := Seq("2.13.0")
-
-scalacOptions ++= Seq("-opt-warnings", "-language:higherKinds", "-deprecation", "-feature", "-Xfatal-warnings")
-scalacOptions in (Compile, doc) ++= Seq("-implicits", "-groups")
-
-testOptions += Tests.Argument(TestFrameworks.JUnit, "-q", "-v", "-s", "-a")
-parallelExecution in Test := false  // why?
-
-mimaPreviousVersion := Some("0.1.0")
-
-homepage := Some(url("https://github.com/scala/scala-collection-contrib"))
-licenses := Seq("Apache-2.0" -> url("https://www.apache.org/licenses/LICENSE-2.0"))
-
-libraryDependencies ++= Seq(
-  "junit"            % "junit"           % "4.12"   % Test,
-  "com.novocode"     % "junit-interface" % "0.11"   % Test,
-  "org.openjdk.jol"  % "jol-core"        % "0.9"    % Test
-)
+lazy val root = project.in(file("."))
+  .aggregate(`scala-collection-contribJS`, `scala-collection-contribJVM`)
+  .settings(
+    disablePublishing,
+    // HACK If we don’t add this dependency the tests compilation of the aggregated projects fails
+    libraryDependencies += "junit" % "junit" % "4.12" % Test
+  )
+
+lazy val `scala-collection-contrib` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .withoutSuffixFor(JVMPlatform).in(file("."))
+  .settings(scalaModuleSettings)
+  .jvmSettings(scalaModuleSettingsJVM)
+  .settings(
+    name := "scala-collection-contrib",
+    version := "0.1.1-SNAPSHOT",
+
+    crossScalaVersions in ThisBuild := Seq("2.13.0"),
+
+    scalacOptions ++= Seq("-opt-warnings", "-language:higherKinds", "-deprecation", "-feature", "-Xfatal-warnings"),
+    scalacOptions in (Compile, doc) ++= Seq("-implicits", "-groups"),
+
+    testOptions += Tests.Argument(TestFrameworks.JUnit, "-q", "-v", "-s", "-a"),
+    parallelExecution in Test := false,  // why?
+
+    mimaPreviousVersion := Some("0.1.0"),
+
+    homepage := Some(url("https://github.com/scala/scala-collection-contrib")),
+    licenses := Seq("Apache-2.0" -> url("https://www.apache.org/licenses/LICENSE-2.0")),
+
+    libraryDependencies ++= Seq(
+      "junit"            % "junit"           % "4.12"   % Test,
+      "com.novocode"     % "junit-interface" % "0.11"   % Test,
+      "org.openjdk.jol"  % "jol-core"        % "0.9"    % Test
+    )
+  )
+  .jsConfigure(_.enablePlugins(ScalaJSJUnitPlugin))
+  .jsSettings(
+    mimaPreviousVersion := None,
+    // Scala.js cannot run forked tests
+    fork in Test := false
+  )
+
+lazy val `scala-collection-contribJVM` = `scala-collection-contrib`.jvm
+lazy val `scala-collection-contribJS` = `scala-collection-contrib`.js

project/plugins.sbt

@@ -1,3 +1,7 @@
 scalacOptions ++= Seq("-deprecation", "-feature", "-Xfatal-warnings")
 
+val scalajsVersion = Option(System.getenv("SCALAJS_VERSION")).filter(_.nonEmpty).getOrElse("0.6.28")
+
 addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "2.0.0")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % scalajsVersion)
+addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "0.6.1")