WIP

sbt-scalajs-bundler/src/main/scala/scalajsbundler/ExternalCommand.scala

@@ -10,7 +10,7 @@ import scalajsbundler.util.Commands
   *
   * @param name Name of the command to run
   */
-class ExternalCommand(name: String) {
+abstract class PackageManager(name: String, args: Seq[String]) {
 
   /**
     * Runs the command `cmd`
@@ -28,20 +28,13 @@ class ExternalCommand(name: String) {
 
 }
 
-object Npm extends ExternalCommand("npm")
+trait LockFileSupport {
+  val lockFileName: String
 
-object Yarn extends ExternalCommand("yarn")
-
-object ExternalCommand {
-  private val yarnOptions = List("--non-interactive", "--mutex", "network")
-
-  private def syncLockfile(
-    lockFileName: String,
+  def lockFileRead(
     baseDir: File,
     installDir: File,
     logger: Logger
-  )(
-      command: => Unit
   ): Unit = {
     val sourceLockFile = baseDir / lockFileName
     val targetLockFile = installDir / lockFileName
@@ -50,34 +43,39 @@ object ExternalCommand {
       logger.info("Using lockfile " + sourceLockFile)
       IO.copyFile(sourceLockFile, targetLockFile)
     }
+  }
 
-    command
+  def lockFileWrite(
+    baseDir: File,
+    installDir: File,
+    logger: Logger
+  ): Unit = {
+    val sourceLockFile = baseDir / lockFileName
+    val targetLockFile = installDir / lockFileName
 
     if (targetLockFile.exists()) {
       logger.debug("Wrote lockfile to " + sourceLockFile)
       IO.copyFile(targetLockFile, sourceLockFile)
     }
   }
+}
 
-  private def syncYarnLockfile(
-    baseDir: File,
-    installDir: File,
-    logger: Logger
-  )(
-    command: => Unit
-  ): Unit = {
-    syncLockfile("yarn.lock", baseDir, installDir, logger)(command)
-  }
+case class Npm(
+    args: Seq[String] = Seq.empty,
+    lockFileName: String = "package-lock.json"
+) extends PackageManager("npm", args)
+    with LockFileSupport
+
+case class Yarn(
+    args: Seq[String] = Yarn.DefaultArgs,
+    lockFileName: String = "yarn.lock"
+) extends PackageManager("yarn", args)
+    with LockFileSupport
+object Yarn {
+  val DefaultArgs: Seq[String] = Seq("--non-interactive", "--mutex", "network")
+}
 
-  private def syncNpmLockfile(
-    baseDir: File,
-    installDir: File,
-    logger: Logger
-  )(
-    command: => Unit
-  ): Unit = {
-    syncLockfile("package-lock.json", baseDir, installDir, logger)(command)
-  }
+object PackageManager {
 
   /**
     * Locally install NPM packages
@@ -91,10 +89,13 @@ object ExternalCommand {
     */
   def addPackages(baseDir: File,
                   installDir: File,
-                  useYarn: Boolean,
                   logger: Logger,
-                  npmExtraArgs: Seq[String],
-                  yarnExtraArgs: Seq[String])(npmPackages: String*): Unit =
+                  packageManager: PackageManager
+                  )(npmPackages: String*): Unit = {
+    val maybeLockFileWrapper = packageManager match {
+      case lfs: LockFileSupport  => () =>
+      case _ =>
+    }
     if (useYarn) {
       syncYarnLockfile(baseDir, installDir, logger) {
         Yarn.run("add" +: (yarnOptions ++ yarnExtraArgs ++ npmPackages): _*)(
@@ -106,10 +107,10 @@ object ExternalCommand {
         Npm.run("install" +: (npmPackages ++ npmExtraArgs): _*)(installDir, logger)
       }
     }
+  }
 
   def install(baseDir: File,
               installDir: File,
-              useYarn: Boolean,
               logger: Logger,
               npmExtraArgs: Seq[String],
               yarnExtraArgs: Seq[String]): Unit =

sbt-scalajs-bundler/src/main/scala/scalajsbundler/sbtplugin/ScalaJSBundlerPlugin.scala

@@ -5,8 +5,9 @@ import org.scalajs.sbtplugin.{ScalaJSPlugin, Stage}
 import sbt.Keys._
 import sbt.{Def, _}
 import scalajsbundler.{BundlerFile, NpmDependencies, Webpack, WebpackDevServer}
-
 import scalajsbundler.ExternalCommand.addPackages
+import scalajsbundler.Npm
+import scalajsbundler.PackageManager
 import scalajsbundler.util.{JSON, ScalaJSNativeLibraries}
 
 
@@ -205,18 +206,6 @@ object ScalaJSBundlerPlugin extends AutoPlugin {
     val additionalNpmConfig: SettingKey[Map[String, JSON]] =
       settingKey[Map[String, JSON]]("Additional option to include in the generated 'package.json'")
 
-    /**
-      * Additional arguments for npm
-      *
-      * Defaults to an empty list.
-      *
-      * @group settings
-      */
-    val npmExtraArgs = SettingKey[Seq[String]](
-      "npmExtraArgs",
-      "Custom arguments for npm"
-    )
-
     /**
       * [[scalajsbundler.BundlingMode]] to use.
       *
@@ -394,19 +383,10 @@ object ScalaJSBundlerPlugin extends AutoPlugin {
       "Custom arguments to node.js when running webpack tasks"
     )
 
-    /**
-      * Whether to use [[https://yarnpkg.com/ Yarn]] to fetch dependencies instead
-      * of `npm`. Yarn has a caching mechanism that makes the process faster.
-      *
-      * If set to `true`, it requires Yarn 0.22.0+ to be available on the
-      * host platform.
-      *
-      * Defaults to `false`.
-      *
-      * @group settings
-      */
-    val useYarn: SettingKey[Boolean] =
-      settingKey[Boolean]("Whether to use yarn for updates")
+    val packageManager = SettingKey[PackageManager](
+      "packageManager",
+      "Package manager which will be used for fetching dependencies. Constructor also allows definition of extra arguments."
+    )
 
     /**
       * Port, on which webpack-dev-server will be launched.
@@ -421,17 +401,6 @@ object ScalaJSBundlerPlugin extends AutoPlugin {
       "Port, on which webpack-dev-server operates"
     )
 
-    /**
-      * Additional arguments for yarn
-      *
-      * Defaults to an empty list.
-      *
-      * @group settings
-      */
-    val yarnExtraArgs = SettingKey[Seq[String]](
-      "yarnExtraArgs",
-      "Custom arguments for yarn"
-    )
     /**
       * Additional arguments to webpack-dev-server.
       *
@@ -568,7 +537,7 @@ object ScalaJSBundlerPlugin extends AutoPlugin {
     // Include the manifest in the produced artifact
     (products in Compile) := (products in Compile).dependsOn(scalaJSBundlerManifest).value,
 
-    useYarn := false,
+    packageManager := Npm(),
 
     ensureModuleKindIsCommonJSModule := {
       if (scalaJSLinkerConfig.value.moduleKind == ModuleKind.CommonJSModule) true
@@ -585,9 +554,6 @@ object ScalaJSBundlerPlugin extends AutoPlugin {
     webpackExtraArgs := Seq.empty,
     webpackNodeArgs := Seq.empty,
 
-    npmExtraArgs := Seq.empty,
-    yarnExtraArgs := Seq.empty,
-
     // The defaults are specified at top level.
     webpackDevServerPort := 8080,
     webpackDevServerExtraArgs := Seq(),