Gradle: npm integration using yarn

#KT-31018 Fixed

libraries/tools/kotlin-gradle-plugin-api/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/HasKotlinDependencies.kt

@@ -43,6 +43,9 @@ interface KotlinDependencyHandler {
         project(listOf("path", "configuration").zip(listOfNotNull(path, configuration)).toMap())
 
     fun project(notation: Map<String, Any?>): ProjectDependency
+
+    fun npm(packageName: String, version: String = "*"): Dependency?
+    fun npm(org: String, packageName: String, version: String = "*"): Dependency?
 }
 
 interface HasKotlinDependencies {

libraries/tools/kotlin-gradle-plugin/build.gradle.kts

@@ -46,6 +46,7 @@ dependencies {
     compileOnly(project(":kotlin-scripting-compiler-impl"))
 
     compile("com.google.code.gson:gson:${rootProject.extra["versions.jar.gson"]}")
+    compile("de.undercouch:gradle-download-task:3.4.3")
     
     compileOnly("com.android.tools.build:gradle:2.0.0")
     compileOnly("com.android.tools.build:gradle-core:2.0.0")

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/ProcessedFilesCache.kt

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.internal
+
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonParseException
+import org.gradle.api.Project
+import org.gradle.api.internal.project.ProjectInternal
+import org.gradle.internal.hash.FileHasher
+import org.jetbrains.kotlin.daemon.common.toHexString
+import java.io.File
+
+/**
+ * Cache for preventing processing some files twice.
+ * Files are precessed some subdirectories of [targetDir] called `target`.
+ * For each target [getOrCompute] should be called.
+ * Absent target directories will be deleted on [close].
+ * `compute` will be called only for source files that was changed since last processing.
+ *
+ * See [org.jetbrains.kotlin.gradle.targets.js.npm.GradleNodeModuleBuilder] for example.
+ *
+ * @param version When updating logic in `compute`, `version` should be increased to invalidate cache
+ */
+internal class ProcessedFilesCache(
+    val project: Project,
+    val targetDir: File,
+    stateFileName: String,
+    val version: String
+) : AutoCloseable {
+    private val hasher = (project as ProjectInternal).services.get(FileHasher::class.java)
+    private val gson = GsonBuilder().setPrettyPrinting().create()
+
+    private class State {
+        var version: String? = null
+        val visited: MutableMap<String, Element> = mutableMapOf()
+
+        operator fun get(elementHash: ByteArray) =
+            visited[elementHash.toHexString()]
+
+        operator fun set(elementHash: ByteArray, element: Element) {
+            visited[elementHash.toHexString()] = element
+        }
+    }
+
+    class Element(
+        val src: String,
+        val target: String?
+    )
+
+    private val stateFile = targetDir.resolve(stateFileName)
+    private val old: State
+
+    init {
+        targetDir.mkdirs()
+
+        val state: State? = if (stateFile.exists()) try {
+            stateFile.reader().use {
+                gson.fromJson(it, State::class.java)
+            }.let {
+                if (it.version != version) null else it
+            }
+        } catch (e: JsonParseException) {
+            project.logger.warn("Cannot read $stateFile", e)
+            if (targetDir.exists()) {
+                targetDir.deleteRecursively()
+            }
+            null
+        } else null
+
+        old = state ?: State()
+    }
+
+    private val new = State()
+
+    init {
+        new.version = version
+    }
+
+    internal fun getOrCompute(
+        file: File,
+        compute: () -> String?
+    ) {
+        val hash = hasher.hash(file).toByteArray()
+        val old = old[hash]
+        if (old != null) {
+            new[hash] = old
+        } else {
+            val key = compute()
+            new[hash] = Element(file.canonicalPath, key)
+        }
+    }
+
+    fun deleteTarget(key: String) {
+        targetDir.resolve(key).deleteRecursively()
+    }
+
+    val targets: Collection<String>
+        get() = new.visited.mapNotNullTo(mutableSetOf()) { it.value.target }
+
+    private fun getDeletedTargets(): MutableSet<String> {
+        val result = mutableSetOf<String>()
+
+        old.visited.forEach {
+            val target = it.value.target
+            if (target != null) {
+                result.add(target)
+            }
+        }
+
+        new.visited.forEach {
+            val target = it.value.target
+            if (target != null) {
+                result.remove(target)
+            }
+        }
+        return result
+    }
+
+    override fun close() {
+        getDeletedTargets().forEach {
+            deleteTarget(it)
+        }
+
+        stateFile.writer().use {
+            gson.toJson(new, it)
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/DefaultKotlinDependencyHandler.kt

@@ -6,6 +6,7 @@ import org.gradle.api.artifacts.ExternalModuleDependency
 import org.gradle.api.artifacts.ProjectDependency
 import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
 import org.jetbrains.kotlin.gradle.plugin.KotlinDependencyHandler
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmDependency
 
 class DefaultKotlinDependencyHandler(
     val parent: HasKotlinDependencies,
@@ -77,4 +78,10 @@ class DefaultKotlinDependencyHandler(
             configure(it)
             project.dependencies.add(configurationName, it)
         }
+
+    override fun npm(packageName: String, version: String) =
+        NpmDependency(project, null, packageName, version)
+
+    override fun npm(org: String, packageName: String, version: String) =
+        NpmDependency(project, org, packageName, version)
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsCompilationTestsConfigurator.kt

@@ -1,12 +1,9 @@
 package org.jetbrains.kotlin.gradle.targets.js
 
-import org.gradle.api.file.FileCollection
 import org.gradle.language.base.plugins.LifecycleBasePlugin
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationToRunnableFiles
-import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExtension
 import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
-import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsSetupTask
-import org.jetbrains.kotlin.gradle.targets.js.tasks.*
+import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinJsTest
 import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
 import org.jetbrains.kotlin.gradle.tasks.registerTask
 import org.jetbrains.kotlin.gradle.testing.internal.configureConventions
@@ -36,81 +33,28 @@ internal class KotlinJsCompilationTestsConfigurator(
         return components.first() + components.drop(1).joinToString("") { it.capitalize() }
     }
 
-    @Suppress("SameParameterValue")
-    private fun disambiguateUnderscored(name: String, includeCompilation: Boolean) =
-        disambiguate(name, includeCompilation).joinToString("_")
-
     private val testTaskName: String
         get() = disambiguateCamelCased("test", false)
 
-    private val nodeModulesDir
-        get() = project.buildDir.resolve(disambiguateUnderscored("node_modules", true))
-
-    private val compileTask: Kotlin2JsCompile
-        get() = project.tasks.findByName(compileTestKotlin2Js.name) as Kotlin2JsCompile
-
-    private val Kotlin2JsCompile.jsRuntimeClasspath: FileCollection
-        get() = classpath.plus(project.files(destinationDir))
-
     fun configure() {
-        compilation.dependencies {
-            implementation(kotlin("test-nodejs-runner"))
-        }
+        // apply plugin (cannot do it lazy)
+        val nodeJs = NodeJsPlugin.apply(target.project)
 
-        val nodeModulesTask = registerTask(
-            project,
-            disambiguateCamelCased("nodeModules", true),
-            KotlinJsNodeModulesTask::class.java
-        ) {
-            it.dependsOn(compileTestKotlin2Js)
-
-            it.onlyIf {
-                compileTestKotlin2Js.outputFile.exists()
-            }
-
-            it.nodeModulesDir = nodeModulesDir
-            it.classpath = compileTask.jsRuntimeClasspath
-        }
-
-        val projectWithNodeJsPlugin = NodeJsPlugin.ensureAppliedInHierarchy(target.project)
-
-        val testTask = registerTask(project, testTaskName, KotlinNodeJsTestTask::class.java) { testJs ->
+        registerTask(project, testTaskName, KotlinJsTest::class.java) { testJs ->
             testJs.group = LifecycleBasePlugin.VERIFICATION_GROUP
 
-            testJs.dependsOn(nodeModulesTask.getTaskOrProvider())
+            testJs.dependsOn(compileTestKotlin2Js, nodeJs.nodeJsSetupTask)
 
             testJs.onlyIf {
                 compileTestKotlin2Js.outputFile.exists()
             }
 
-            if (disambiguationClassifier != null) {
-                testJs.targetName = disambiguationClassifier
-                testJs.showTestTargetName = true
-            }
-
-            testJs.nodeJsProcessOptions.workingDir = project.projectDir
-
-            testJs.nodeModulesDir = nodeModulesDir
-            testJs.testRuntimeNodeModules = listOf(
-                "kotlin-test-nodejs-runner.js",
-                "kotlin-nodejs-source-map-support.js"
-            )
-            testJs.nodeModulesToLoad = setOf(compileTestKotlin2Js.outputFile.name)
+            testJs.runtimeDependencyHandler = compilation
+            testJs.targetName = disambiguationClassifier
+            testJs.nodeModulesToLoad.add(compileTestKotlin2Js.outputFile.name)
 
             testJs.configureConventions()
             registerTestTask(testJs)
         }
-
-        project.afterEvaluate {
-            // defer nodeJs executable setup, as nodejs project settings may change during configuration
-            testTask.configure {
-                val nodeJsSetupTask = projectWithNodeJsPlugin.tasks.findByName(NodeJsSetupTask.NAME)
-                it.dependsOn(nodeJsSetupTask)
-
-                if (it.nodeJsProcessOptions.executable == null) {
-                    it.nodeJsProcessOptions.executable = NodeJsExtension[projectWithNodeJsPlugin].buildEnv().nodeExec
-                }
-            }
-        }
     }
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsTargetConfigurator.kt

@@ -8,6 +8,8 @@ package org.jetbrains.kotlin.gradle.targets.js
 import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinOnlyTarget
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmProject
+import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack
 import org.jetbrains.kotlin.gradle.tasks.KotlinTasksProvider
 
 class KotlinJsTargetConfigurator(kotlinPluginVersion: String) :
@@ -23,13 +25,26 @@ class KotlinJsTargetConfigurator(kotlinPluginVersion: String) :
 
         platformTarget.compilations.all {
             it.compileKotlinTask.kotlinOptions {
-                moduleKind = "umd"
+                moduleKind = "commonjs"
                 sourceMap = true
                 sourceMapEmbedSources = null
             }
         }
     }
 
+    override fun configureTest(target: KotlinOnlyTarget<KotlinJsCompilation>) {
+        val project = target.project
+        val npmProject = NpmProject[project]
+
+        target.compilations.all { compilation ->
+            if (isTestCompilation(compilation)) {
+                KotlinJsCompilationTestsConfigurator(compilation).configure()
+            } else {
+                KotlinWebpack.configure(compilation)
+            }
+        }
+    }
+
     companion object {
         internal fun isTestCompilation(it: KotlinJsCompilation) =
             it.name == KotlinCompilation.TEST_COMPILATION_NAME

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/internal/RewriteSourceMapFilterReader.kt

@@ -142,7 +142,11 @@ open class RewriteSourceMapFilterReader(
     }
 
     protected open fun transformString(value: String): String =
-        File(srcSourceRoot).resolve(value).canonicalFile.relativeToOrSelf(File(targetSourceRoot)).path
+        File(srcSourceRoot)
+            .resolve(value)
+            .canonicalFile
+            .relativeToOrSelf(File(targetSourceRoot))
+            .path
 
     override fun read(): Int {
         maybeReadFirst()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsEnv.kt

@@ -1,16 +1,16 @@
 package org.jetbrains.kotlin.gradle.targets.js.nodejs
 
-import java.io.*
+import java.io.File
 
 internal data class NodeJsEnv(
-        val nodeDir: File,
-        val nodeBinDir: File,
-        val nodeExec: String,
-        val npmExec: String,
+    val nodeDir: File,
+    val nodeBinDir: File,
+    val nodeExecutable: String,
 
-        val platformName: String,
-        val architectureName: String,
-        val ivyDependency: String
+
+    val platformName: String,
+    val architectureName: String,
+    val ivyDependency: String
 ) {
     val isWindows: Boolean
         get() = platformName == "win"

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsExtension.kt

@@ -1,68 +1,31 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
 package org.jetbrains.kotlin.gradle.targets.js.nodejs
 
-import org.gradle.api.GradleException
 import org.gradle.api.Project
-import org.jetbrains.kotlin.gradle.logging.kotlinInfo
-import java.io.File
+import org.jetbrains.kotlin.gradle.targets.js.npm.PackageJson
 
-open class NodeJsExtension(project: Project) {
-    private val gradleHome = project.gradle.gradleUserHomeDir.also {
-        project.logger.kotlinInfo("Storing cached files in $it")
-    }
+open class NodeJsExtension(val project: Project) {
+    val root: NodeJsRootExtension
+        get() = this as? NodeJsRootExtension ?: NodeJsRootExtension[project]
 
-    var installationDir = gradleHome.resolve("nodejs")
+    internal val packageJsonHandlers = mutableListOf<PackageJson.() -> Unit>()
 
-    var distBaseUrl = "https://nodejs.org/dist"
-    var version = "10.15.3"
-    var npmVersion = ""
-
-    var nodeCommand = "node"
-    var npmCommand = "npm"
-
-    var download = true
-
-    internal fun buildEnv(): NodeJsEnv {
-        val platform = NodeJsPlatform.name
-        val architecture = NodeJsPlatform.architecture
-
-        val nodeDir = installationDir.resolve("node-v$version-$platform-$architecture")
-        val isWindows = NodeJsPlatform.name == NodeJsPlatform.WIN
-        val nodeBinDir = if (isWindows) nodeDir else nodeDir.resolve("bin")
-
-        fun getExecutable(command: String, customCommand: String, windowsExtension: String): String {
-            val finalCommand = if (isWindows && customCommand == command) "$command.$windowsExtension" else customCommand
-            return if (download) File(nodeBinDir, finalCommand).absolutePath else finalCommand
-        }
-
-        fun getIvyDependency(): String {
-            val type = if (isWindows) "zip" else "tar.gz"
-            return "org.nodejs:node:$version:$platform-$architecture@$type"
-        }
-
-        return NodeJsEnv(
-                nodeDir = nodeDir,
-                nodeBinDir = nodeBinDir,
-                nodeExec = getExecutable("node", nodeCommand, "exe"),
-                npmExec = getExecutable("npm", npmCommand, "cmd"),
-                platformName = platform,
-                architectureName = architecture,
-                ivyDependency = getIvyDependency()
-        )
+    @Suppress("unused")
+    fun packageJson(handler: PackageJson.() -> Unit) {
+        packageJsonHandlers.add(handler)
     }
 
     companion object {
-        const val NODE_JS: String = "nodeJs"
-
         operator fun get(project: Project): NodeJsExtension {
-            val extension = project.extensions.findByType(NodeJsExtension::class.java)
-            if (extension != null)
-                return extension
-
-            val parentProject = project.parent
-            if (parentProject != null)
-                return get(parentProject)
-
-            throw GradleException("NodeJsExtension is not installed")
+            NodeJsPlugin.apply(project.rootProject)
+            return project.extensions.getByName(NodeJsRootExtension.NODE_JS) as NodeJsExtension
         }
     }
 }
+
+val Project.nodeJs: NodeJsExtension
+    get() = NodeJsExtension[this]

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsPlatform.kt

@@ -2,7 +2,7 @@ package org.jetbrains.kotlin.gradle.targets.js.nodejs
 
 /**
  * Provides platform and architecture names that is used to download NodeJs.
- * See [NodeJsEnv.ivyDependency] that is filled in [NodeJsExtension.buildEnv].
+ * See [NodeJsEnv.ivyDependency] that is filled in [NodeJsRootExtension.environment].
  */
 internal object NodeJsPlatform {
     private val props = System.getProperties()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsPlugin.kt

@@ -2,28 +2,46 @@ package org.jetbrains.kotlin.gradle.targets.js.nodejs
 
 import org.gradle.api.Plugin
 import org.gradle.api.Project
-import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExtension.Companion.NODE_JS
+import org.gradle.api.plugins.BasePlugin
+import org.gradle.api.tasks.Delete
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension.Companion.NODE_JS
 
 open class NodeJsPlugin : Plugin<Project> {
     override fun apply(project: Project): Unit = project.run {
-        this.extensions.create(NODE_JS, NodeJsExtension::class.java, this)
+        check(project == project.rootProject) {
+            "NodeJsPlugin can be applied only to root project"
+        }
+
+        this.extensions.create(NODE_JS, NodeJsRootExtension::class.java, this)
         tasks.create(NodeJsSetupTask.NAME, NodeJsSetupTask::class.java)
+
+        setupCleanNodeModulesTask(project)
+
+        allprojects {
+            if (it != project) {
+                it.extensions.create(NODE_JS, NodeJsExtension::class.java, this)
+            }
+        }
+    }
+
+    private fun setupCleanNodeModulesTask(project: Project) {
+        project.tasks.create("cleanNodeModules", Delete::class.java) {
+            it.description = "Deletes node_modules and package.json file"
+            it.group = BasePlugin.BUILD_GROUP
+
+            it.doLast {
+                project.nodeJs.root.packageManager.cleanProject(project)
+            }
+
+            project.tasks.maybeCreate(BasePlugin.CLEAN_TASK_NAME).dependsOn(it)
+        }
     }
 
     companion object {
-        fun ensureAppliedInHierarchy(myProject: Project): Project =
-                findInHeirarchy(myProject) ?: myProject.also {
-                    it.pluginManager.apply(NodeJsPlugin::class.java)
-                }
-
-        fun findInHeirarchy(myProject: Project): Project? {
-            var project: Project? = myProject
-            while (project != null) {
-                if (myProject.plugins.hasPlugin(NodeJsPlugin::class.java)) return project
-                project = project.parent
-            }
-
-            return null
+        fun apply(project: Project): NodeJsRootExtension {
+            val rootProject = project.rootProject
+            rootProject.plugins.apply(NodeJsPlugin::class.java)
+            return rootProject.extensions.getByName(NODE_JS) as NodeJsRootExtension
         }
     }
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsRootExtension.kt

@@ -0,0 +1,71 @@
+package org.jetbrains.kotlin.gradle.targets.js.nodejs
+
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.logging.kotlinInfo
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmApi
+import org.jetbrains.kotlin.gradle.targets.js.yarn.Yarn
+import java.io.File
+
+open class NodeJsRootExtension(project: Project) : NodeJsExtension(project) {
+    private val gradleHome = project.gradle.gradleUserHomeDir.also {
+        project.logger.kotlinInfo("Storing cached files in $it")
+    }
+
+    var installationDir = gradleHome.resolve("nodejs")
+
+    var download = true
+    var nodeDownloadBaseUrl = "https://nodejs.org/dist"
+    var nodeVersion = "10.15.3"
+
+    var nodeCommand = "node"
+
+    var manageNodeModules: Boolean = false
+    var packageManager: NpmApi = Yarn
+
+    val nodeJsSetupTask: NodeJsSetupTask
+        get() = project.tasks.getByName(NodeJsSetupTask.NAME) as NodeJsSetupTask
+
+    internal val environment: NodeJsEnv
+        get() {
+            val platform = NodeJsPlatform.name
+            val architecture = NodeJsPlatform.architecture
+
+            val nodeDir = installationDir.resolve("node-v$nodeVersion-$platform-$architecture")
+            val isWindows = NodeJsPlatform.name == NodeJsPlatform.WIN
+            val nodeBinDir = if (isWindows) nodeDir else nodeDir.resolve("bin")
+
+            fun getExecutable(command: String, customCommand: String, windowsExtension: String): String {
+                val finalCommand = if (isWindows && customCommand == command) "$command.$windowsExtension" else customCommand
+                return if (download) File(nodeBinDir, finalCommand).absolutePath else finalCommand
+            }
+
+            fun getIvyDependency(): String {
+                val type = if (isWindows) "zip" else "tar.gz"
+                return "org.nodejs:node:$nodeVersion:$platform-$architecture@$type"
+            }
+
+            return NodeJsEnv(
+                nodeDir = nodeDir,
+                nodeBinDir = nodeBinDir,
+                nodeExecutable = getExecutable("node", nodeCommand, "exe"),
+                platformName = platform,
+                architectureName = architecture,
+                ivyDependency = getIvyDependency()
+            )
+        }
+
+    internal fun executeSetup() {
+        val nodeJsEnv = environment
+        if (download) {
+            if (!nodeJsEnv.nodeBinDir.isDirectory) {
+                nodeJsSetupTask.exec()
+            }
+        }
+    }
+
+    companion object {
+        const val NODE_JS: String = "nodeJs"
+
+        operator fun get(project: Project) = NodeJsPlugin.apply(project)
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsSetupTask.kt

@@ -11,30 +11,33 @@ import java.io.File
 import java.net.URI
 
 open class NodeJsSetupTask : DefaultTask() {
-    private val settings = NodeJsExtension[project]
-    private val env by lazy { settings.buildEnv() }
+    private val settings = project.nodeJs.root
+    private val env by lazy { settings.environment }
 
     init {
-        group = NodeJsExtension.NODE_JS
+        group = NodeJsRootExtension.NODE_JS
         description = "Download and install a local node/npm version."
     }
 
-    val input: Set<String>
-        @Input get() = setOf(settings.download.toString(), env.ivyDependency)
+    val ivyDependency: String
+        @Input get() = env.ivyDependency
 
     val destination: File
         @OutputDirectory get() = env.nodeDir
 
+    init {
+        onlyIf {
+            settings.download && !env.nodeBinDir.isDirectory
+        }
+    }
+
     @Suppress("unused")
     @TaskAction
     fun exec() {
-        if (!settings.download)
-            return
-
         @Suppress("UnstableApiUsage", "DEPRECATION")
         val repo = project.repositories.ivy { repo ->
-            repo.name = "Node Distributions at ${settings.distBaseUrl}"
-            repo.url = URI(settings.distBaseUrl)
+            repo.name = "Node Distributions at ${settings.nodeDownloadBaseUrl}"
+            repo.url = URI(settings.nodeDownloadBaseUrl)
 
             if (isGradleVersionAtLeast(5, 0)) {
                 repo.patternLayout { layout ->
@@ -52,7 +55,7 @@ open class NodeJsSetupTask : DefaultTask() {
             }
         }
 
-        val dep = this.project.dependencies.create(env.ivyDependency)
+        val dep = this.project.dependencies.create(ivyDependency)
         val conf = this.project.configurations.detachedConfiguration(dep)
         conf.isTransitive = false
         val result = conf.resolve().single()
@@ -63,7 +66,7 @@ open class NodeJsSetupTask : DefaultTask() {
         unpackNodeArchive(result, destination.parentFile) // parent because archive contains name already
 
         if (!env.isWindows) {
-            File(env.nodeExec).setExecutable(true)
+            File(env.nodeExecutable).setExecutable(true)
         }
     }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/utils.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.nodejs
+
+import org.gradle.api.Project
+
+internal fun nodeJsSetupWithoutTasks(project: Project) {
+    val nodeJsProject = NodeJsPlugin.ensureAppliedInHierarchy(project)
+    val nodeJs = NodeJsExtension[nodeJsProject]
+    val nodeJsEnv = nodeJs.buildEnv()
+    if (nodeJs.download) {
+        if (!nodeJsEnv.nodeBinDir.isDirectory) {
+            (nodeJsProject.tasks.findByName(NodeJsSetupTask.NAME) as NodeJsSetupTask).exec()
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModule.kt

@@ -0,0 +1,10 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import java.io.File
+
+class GradleNodeModule(val name: String, val path: File)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilder.kt

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import org.gradle.api.Project
+import org.gradle.api.artifacts.ResolvedArtifact
+import org.gradle.api.artifacts.ResolvedDependency
+import java.io.File
+
+internal class GradleNodeModuleBuilder(
+    val project: Project,
+    val dependency: ResolvedDependency,
+    val artifacts: Set<ResolvedArtifact>,
+    val cache: GradleNodeModules
+) {
+    var srcPackageJsonFile: File? = null
+    val files = mutableListOf<File>()
+
+    fun visitArtifacts() {
+        artifacts.forEach { artifact ->
+            val srcFile = artifact.file
+            when {
+                isKotlinJsRuntimeFile(srcFile) -> files.add(srcFile)
+                srcFile.isZip -> project.zipTree(srcFile).forEach { innerFile ->
+                    when {
+                        innerFile.name == NpmProject.PACKAGE_JSON -> srcPackageJsonFile = innerFile
+                        isKotlinJsRuntimeFile(innerFile) -> files.add(innerFile)
+                    }
+                }
+            }
+        }
+    }
+
+    fun rebuild(): File? {
+        if (files.isEmpty()) return null
+
+        val packageJson = srcPackageJsonFile?.reader()?.use {
+            Gson().fromJson(it, PackageJson::class.java)
+        } ?: PackageJson(dependency.moduleName, dependency.moduleVersion)
+
+        val jsFiles = files.filter { it.name.endsWith(".js") }
+        if (jsFiles.size == 1) {
+            val jsFile = jsFiles.single()
+            packageJson.name = jsFile.nameWithoutExtension
+            packageJson.main = jsFile.name
+        }
+
+        // yarn requires semver
+        packageJson.version = fixSemver(packageJson.version)
+
+        return makeNodeModule(cache.dir, packageJson) { nodeModule ->
+            project.copy { copy ->
+                copy.from(files)
+                copy.into(nodeModule)
+            }
+        }
+    }
+}
+
+private val File.isZip
+    get() = isFile && (name.endsWith(".jar") || name.endsWith(".zip"))
+
+private fun isKotlinJsRuntimeFile(file: File): Boolean {
+    if (!file.isFile) return false
+    val name = file.name
+    return (name.endsWith(".js") && !name.endsWith(".meta.js"))
+            || name.endsWith(".js.map")
+}
+
+internal fun fixSemver(version: String): String {
+    val c = version.split("-", limit = 2)
+    val main = c[0]
+    val preRelease = if (c.size > 1) c[1] else null
+    val numbers = main.split(".")
+    val major = numbers[0]
+    val minor = if (numbers.size > 1) numbers[1] else null
+    val patch = if (numbers.size > 2) numbers[2] else null
+    return buildString {
+        append(major.filter { it.isDigit() })
+        append(".")
+        append(minor?.filter { it.isDigit() } ?: "0")
+        append(".")
+        append(patch?.filter { it.isDigit() } ?: "0")
+        if (preRelease != null) {
+            append("-")
+            append(preRelease)
+        }
+    }
+}
+
+fun makeNodeModule(
+    container: File,
+    packageJson: PackageJson,
+    files: (File) -> Unit
+): File {
+    val dir = container.resolve(packageJson.name)
+
+    if (dir.exists()) dir.deleteRecursively()
+
+    check(dir.mkdirs()) {
+        "Cannot create directory: $dir"
+    }
+
+    val gson = GsonBuilder()
+        .setPrettyPrinting()
+        .create()
+
+    files(dir)
+
+    dir.resolve("package.json").writer().use {
+        gson.toJson(packageJson, it)
+    }
+
+    return dir
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModules.kt

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import org.gradle.api.Project
+import org.gradle.api.artifacts.ResolvedArtifact
+import org.gradle.api.artifacts.ResolvedDependency
+import org.gradle.api.file.CopySpec
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.internal.ProcessedFilesCache
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
+import org.jetbrains.kotlin.gradle.targets.js.internal.RewriteSourceMapFilterReader
+import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
+
+internal class GradleNodeModules(val project: Project) : AutoCloseable {
+    companion object {
+        const val STATE_FILE_NAME = ".visited"
+    }
+
+    internal val dir = project.buildDir.resolve("node_modules_gradle")
+    private val nodeModulesDir = project.npmProject.nodeModulesDir
+    private val cache = ProcessedFilesCache(project, dir, STATE_FILE_NAME, "5")
+    private val visited = mutableSetOf<ResolvedDependency>()
+    private val doLast = mutableListOf<() -> Unit>()
+
+    val modules
+        get() = cache.targets.map {
+            GradleNodeModule(it, dir.resolve(it))
+        }
+
+    fun visitCompilation(compilation: KotlinCompilation<KotlinCommonOptions>) {
+        val project = compilation.target.project
+        val kotlin2JsCompile = compilation.compileKotlinTask as Kotlin2JsCompile
+
+        // classpath
+        compilation.relatedConfigurationNames.forEach {
+            val configuration = project.configurations.getByName(it)
+            if (configuration.isCanBeResolved) {
+                configuration.resolvedConfiguration.firstLevelModuleDependencies.forEach {
+                    visitDependency(compilation, it)
+                }
+            }
+        }
+
+        // output
+        doLast.add {
+            // we should do it only after node package manger work (as it can clean files)
+            if (kotlin2JsCompile.state.executed) {
+                visitCompile(project, kotlin2JsCompile)
+            } else {
+                kotlin2JsCompile.doLast {
+                    visitCompile(project, kotlin2JsCompile)
+                }
+            }
+        }
+    }
+
+    private fun visitDependency(
+        compilation: KotlinCompilation<KotlinCommonOptions>,
+        dependency: ResolvedDependency
+    ) {
+        if (!visited.add(dependency)) return
+
+        visitArtifacts(dependency, dependency.moduleArtifacts)
+
+        dependency.children.forEach {
+            visitDependency(compilation, it)
+        }
+    }
+
+    private fun visitArtifacts(
+        dependency: ResolvedDependency,
+        artifacts: MutableSet<ResolvedArtifact>
+    ) {
+        val lazyDirName: String? by lazy {
+            val module = GradleNodeModuleBuilder(project, dependency, artifacts, this)
+            module.visitArtifacts()
+            module.rebuild()?.canonicalFile?.relativeTo(dir)?.path
+        }
+
+        artifacts.forEach { artifact ->
+            cache.getOrCompute(artifact.file) {
+                lazyDirName
+            }
+        }
+    }
+
+    private fun visitCompile(project: Project, kotlin2JsCompile: Kotlin2JsCompile) {
+        project.copy { copy ->
+            copy.from(kotlin2JsCompile.outputFile)
+            copy.from(kotlin2JsCompile.outputFile.path + ".map")
+            copy.into(nodeModulesDir)
+            copy.withSourceMapRewriter()
+        }
+    }
+
+    private fun CopySpec.withSourceMapRewriter() {
+        eachFile {
+            if (it.name.endsWith(".js.map")) {
+                it.filter(
+                    mapOf(
+                        "srcSourceRoot" to it.file.parentFile,
+                        "targetSourceRoot" to nodeModulesDir
+                    ),
+                    RewriteSourceMapFilterReader::class.java
+                )
+            }
+        }
+    }
+
+    override fun close() {
+        doLast.forEach { it() }
+        cache.close()
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NodeModulesGradleComponents.kt

@@ -0,0 +1,148 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonIOException
+import com.google.gson.JsonSyntaxException
+import org.gradle.api.Project
+import org.gradle.api.internal.project.ProjectInternal
+import org.gradle.internal.hash.FileHasher
+import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
+import org.jetbrains.kotlin.gradle.targets.js.tasks.isKotlinJsRuntimeFile
+import org.jetbrains.kotlin.gradle.targets.js.tasks.isZip
+import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
+import java.io.File
+
+class NodeModulesGradleComponents(val rootProject: Project) {
+    val hasher = (rootProject as ProjectInternal).services.get(FileHasher::class.java)
+    val nodeModulesDir = rootProject.rootDir.resolve("node_modules")
+    val gson = GsonBuilder().setPrettyPrinting().create()
+
+    private class State {
+        val contents: MutableMap<ByteArray, Element> = mutableMapOf()
+    }
+
+    private class Element {
+        val fileNames: MutableList<String> = mutableListOf()
+
+        @Transient
+        val files = mutableListOf<File>()
+    }
+
+    class TransitiveNpmDependency(
+        val project: String,
+        val from: String,
+        val key: String,
+        val version: String
+    )
+
+    private lateinit var old: State
+    private val new = State()
+
+    val stateFile = rootProject.buildDir.resolve("nodeModulesGradleComponents.json")
+
+    fun loadOldState() {
+        val state: State? = if (stateFile.exists()) try {
+            stateFile.reader().use {
+                gson.fromJson(it, State::class.java)
+            }
+        } catch (e: JsonSyntaxException) {
+            // todo: warn
+            null
+        } catch (e: JsonIOException) {
+            // todo: warn
+            null
+        } else null
+
+        old = state ?: State()
+    }
+
+    fun sync() {
+        val children = nodeModulesDir.list()?.toSet() ?: setOf()
+        val deleted = old.contents.keys.toMutableSet()
+        val absense = mutableSetOf<ByteArray>()
+
+        new.contents.forEach { (key, value) ->
+            deleted.remove(key)
+            if (key !in old.contents.keys) absense.add(key)
+            else if (value.fileNames.any { it !in children }) absense.add(key)
+        }
+
+        deleted.forEach {
+            old.contents[it]!!.fileNames.forEach { fileName ->
+                nodeModulesDir.resolve(fileName).delete()
+            }
+        }
+
+        rootProject.copy { copy ->
+            absense.forEach { key ->
+                copy.from(new.contents[key]!!.files)
+                copy.into(nodeModulesDir)
+            }
+        }
+
+        saveNewState()
+    }
+
+    private fun saveNewState() {
+        stateFile.writer().use {
+            gson.toJson(new, it)
+        }
+    }
+
+    private fun getOrCompute(file: File, buildElement: (Element) -> Unit) {
+        val hash = hasher.hash(file).toByteArray()
+        new.contents[hash] = old.contents[hash] ?: Element().also {
+            buildElement(it)
+            it.files.mapTo(it.fileNames) { it.name }
+        }
+    }
+
+    fun visitCompilation(
+        compilation: KotlinCompilation<KotlinCommonOptions>,
+        project: Project,
+        transitiveDependencies: MutableList<TransitiveNpmDependency>
+    ): List<TransitiveNpmDependency> {
+        val kotlin2JsCompile = compilation.compileKotlinTask as Kotlin2JsCompile
+
+        // classpath
+        kotlin2JsCompile.classpath.forEach { srcFile ->
+            when {
+                isKotlinJsRuntimeFile(srcFile) -> getOrCompute(srcFile) { element ->
+                    element.files.add(srcFile)
+                }
+                srcFile.isZip -> getOrCompute(srcFile) { element ->
+                    rootProject.zipTree(srcFile).forEach { innerFile ->
+                        if (innerFile.name == "package.json") {
+                            val packageJson = innerFile.reader().use {
+                                gson.fromJson(it, PackageJson::class.java)
+                            }
+
+                            packageJson.dependencies.forEach { (key, version) ->
+                                transitiveDependencies.add(TransitiveNpmDependency(project.path, srcFile.path, key, version))
+                            }
+                        } else if (isKotlinJsRuntimeFile(innerFile)) {
+                            element.files.add(innerFile)
+                        }
+                    }
+                }
+            }
+        }
+
+        // output
+        kotlin2JsCompile.doLast {
+            project.copy { copy ->
+                copy.from(kotlin2JsCompile.outputFile)
+                copy.from(kotlin2JsCompile.outputFile.path + ".map")
+                copy.into(nodeModulesDir)
+            }
+        }
+
+        return transitiveDependencies
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/Npm.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.nodeJsSetupWithoutTasks
+
+object Npm: NpmApi {
+    override fun setup(project: Project) {
+        nodeJsSetupWithoutTasks(project)
+    }
+
+    override fun resolveRootProject(project: Project) {
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmApi.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import org.gradle.api.Project
+
+interface NpmApi {
+    fun setup(project: Project)
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    fun resolveProject(npmPackage: NpmResolver.NpmPackage)
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    fun resolveRootProject(
+        rootProject: Project,
+        subprojects: MutableList<NpmResolver.NpmPackage>
+    )
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    fun hookRootPackage(rootProject: Project, rootPackageJson: PackageJson, allWorkspaces: Collection<NpmResolver.NpmPackage>) {
+
+    }
+
+    open val hoistGradleNodeModules
+        get() = false
+
+    fun cleanProject(project: Project) {
+        val npmProject = project.npmProject
+
+        npmProject.nodeModulesDir.deleteRecursively()
+        npmProject.packageJsonFile.delete()
+    }
+
+    companion object {
+        fun resolveOperationDescription(packageManagerTitle: String): String =
+            "Resolving NPM dependencies using $packageManagerTitle"
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmDependency.kt

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import org.gradle.api.Project
+import org.gradle.api.artifacts.Dependency
+import org.gradle.api.artifacts.FileCollectionDependency
+import org.gradle.api.artifacts.SelfResolvingDependency
+import org.gradle.api.file.FileCollection
+import org.gradle.api.internal.artifacts.DependencyResolveContext
+import org.gradle.api.internal.artifacts.ResolvableDependency
+import org.gradle.api.internal.artifacts.dependencies.SelfResolvingDependencyInternal
+import org.gradle.api.tasks.TaskDependency
+import org.gradle.internal.component.local.model.DefaultLibraryBinaryIdentifier
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmResolver.ResolutionCallResult.*
+import java.io.File
+
+data class NpmDependency(
+    internal val project: Project,
+    private val org: String?,
+    private val name: String,
+    private val version: String
+) : SelfResolvingDependency,
+    SelfResolvingDependencyInternal,
+    ResolvableDependency,
+    FileCollectionDependency {
+    override fun getGroup(): String? = org
+
+    internal val dependencies = mutableSetOf<NpmDependency>()
+
+    override fun resolve(): MutableSet<File> {
+        resolveProject() ?: return mutableSetOf()
+
+        val all = mutableSetOf<File>()
+        val visited = mutableSetOf<NpmDependency>()
+
+        fun visit(item: NpmDependency) {
+            if (item in visited) return
+            visited.add(item)
+            item.tryFindNodeModule()?.let {
+                all.add(it)
+            }
+        }
+
+        visit(this)
+
+        return all
+    }
+
+    internal fun resolveProject(): NpmResolver.ResolvedProject? {
+        val result = NpmResolver.resolve(project)
+
+        return when (result) {
+            is AlreadyInProgress -> null
+            is AlreadyResolved -> {
+                check(this in result.resolution.dependencies) {
+                    "Project hierarchy is already resolved in NPM without $this"
+                }
+
+                result.resolution
+            }
+            is ResolvedNow -> {
+                check(this in result.resolution.dependencies) {
+                    "$this was not visited during resolution"
+                }
+
+                result.resolution
+            }
+        }
+    }
+
+    private fun tryFindNodeModule(): File? {
+        var p = project
+        do {
+            val result = NpmProject[p].nodeModulesDir.resolve(key)
+            if (result.exists()) return result
+            p = project.parent ?: return null
+        } while (true)
+    }
+
+    val key: String = if (org == null) name else "@$org/$name"
+
+    override fun toString() = "$key: $version"
+
+    override fun resolve(context: DependencyResolveContext) {
+        resolve()
+        dependencies.forEach {
+            context.add(it)
+        }
+    }
+
+    override fun resolve(transitive: Boolean): MutableSet<File> = resolve()
+
+    override fun getFiles(): FileCollection = project.files(resolve())
+
+    override fun getName() = name
+
+    override fun getVersion() = version
+
+    override fun getBuildDependencies(): TaskDependency = TaskDependency { mutableSetOf() }
+
+    override fun contentEquals(dependency: Dependency) = this == dependency
+
+    override fun getTargetComponentId() = DefaultLibraryBinaryIdentifier(project.path, key, "npm")
+
+    override fun copy(): Dependency = this.copy(org = org)
+
+    private var reason: String? = null
+
+    override fun because(reason: String?) {
+        this.reason = reason
+    }
+
+    override fun getReason(): String? = reason
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmProject.kt

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import com.google.gson.Gson
+import com.google.gson.JsonObject
+import groovy.transform.TailRecursive
+import org.gradle.api.Project
+import org.gradle.process.ExecSpec
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.nodeJs
+import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
+import java.io.File
+
+class NpmProject(
+    val project: Project,
+    val nodeWorkDir: File,
+    val managed: Boolean
+) {
+    val nodeModulesDir
+        get() = nodeWorkDir.resolve(NODE_MODULES)
+
+    val packageJsonFile: File
+        get() {
+            return nodeWorkDir.resolve(PACKAGE_JSON)
+        }
+
+    fun useTool(exec: ExecSpec, tool: String, vararg args: String) {
+        NpmResolver.resolve(project)
+
+        exec.workingDir = nodeWorkDir
+        exec.executable = project.nodeJs.root.environment.nodeExecutable
+        exec.args = listOf(findModule(tool)) + args
+    }
+
+    val hoistGradleNodeModules: Boolean
+        get() = project.nodeJs.root.packageManager.getHoistGradleNodeModules(project)
+
+    val gradleNodeModulesDir: File
+        get() =
+            if (hoistGradleNodeModules) project.rootProject.npmProject.nodeModulesDir
+            else nodeModulesDir
+
+    fun moduleOutput(compilationTask: Kotlin2JsCompile): File {
+        return gradleNodeModulesDir.resolve(compilationTask.outputFile.name)
+    }
+
+    @TailRecursive
+    fun findModule(name: String, src: NpmProject = this): String {
+        val file = nodeModulesDir.resolve(name)
+        if (file.isFile) return file.canonicalPath
+        if (file.isDirectory) {
+            val packageJsonFile = file.resolve("package.json")
+            val main: String = (if (packageJsonFile.isFile) {
+                val packageJson = packageJsonFile.reader().use {
+                    Gson().fromJson(it, JsonObject::class.java)
+                }
+
+                packageJson["main"] as? String? ?: packageJson["module"] as? String? ?: packageJson["browser"] as? String?
+            } else null) ?: "index.js"
+
+            val mainFile = file.resolve(main)
+            if (mainFile.isFile) return mainFile.canonicalPath
+        }
+
+        val parent = project.parent
+        return if (!managed || parent == null) error("Cannot find node module $name in $src")
+        else NpmProject[parent].findModule(name, src)
+    }
+
+    companion object {
+        const val PACKAGE_JSON = "package.json"
+        const val NODE_MODULES = "node_modules"
+
+        operator fun get(project: Project): NpmProject {
+            val nodeJsRootExtension = NodeJsPlugin.apply(project)
+
+            val manageNodeModules = nodeJsRootExtension.root.manageNodeModules
+
+            val nodeWorkDir =
+                if (manageNodeModules) project.projectDir
+                else project.buildDir
+
+            return NpmProject(project, nodeWorkDir, manageNodeModules)
+        }
+    }
+}
+
+val Project.npmProject
+    get() = NpmProject[this]

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmResolver.kt

@@ -0,0 +1,218 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
+import org.jetbrains.kotlin.gradle.dsl.KotlinSingleTargetExtension
+import org.jetbrains.kotlin.gradle.dsl.kotlinExtensionOrNull
+import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.nodeJs
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmResolver.ResolutionCallResult.*
+
+/**
+ * Generates `package.json` file for projects with npm or js dependencies and
+ * runs selected [NodeJsRootExtension.packageManager] to download and install it.
+ *
+ * All [NpmDependency] for configurations related to kotlin/js will be added to `package.json`.
+ * For external gradle modules, fake npm packages will be created and added to `package.json`
+ * as path to directory.
+ */
+internal class NpmResolver private constructor(val rootProject: Project) {
+    companion object {
+        fun resolve(project: Project): ResolutionCallResult {
+            val rootProject = project.rootProject
+            val process = ProjectData[rootProject]
+
+            if (process != null && process.resolved == null)
+                return AlreadyInProgress
+
+            val resolved = process?.resolved
+
+            return if (resolved != null) AlreadyResolved(resolved)
+            else {
+                val resolver = NpmResolver(rootProject)
+                check(resolver.resolve(rootProject, null))
+                ResolvedNow(ResolvedProject(resolver.npmPackages))
+            }
+        }
+    }
+
+    sealed class ResolutionCallResult {
+        object AlreadyInProgress : ResolutionCallResult()
+        class AlreadyResolved(val resolution: ResolvedProject) : ResolutionCallResult()
+        class ResolvedNow(val resolution: ResolvedProject) : ResolutionCallResult()
+    }
+
+    private val nodeJs = NodeJsPlugin.apply(rootProject).root
+    private val npmProject = rootProject.npmProject
+    private val packageManager = nodeJs.packageManager
+    private val hoistGradleNodeModules = npmProject.hoistGradleNodeModules
+    private val npmPackages = mutableListOf<NpmPackage>()
+    private val gson = GsonBuilder()
+        .setPrettyPrinting()
+        .create()
+
+    class ProjectData(var resolved: ResolvedProject? = null) {
+        companion object {
+            private const val KEY = "npmResolverData"
+            operator fun get(project: Project) = project.extensions.findByName(KEY) as ProjectData?
+            operator fun set(project: Project, value: ProjectData) = project.extensions.add(KEY, value)
+        }
+    }
+
+    class ResolvedProject(val npmPackages: Collection<NpmPackage>) {
+        val dependencies by lazy {
+            npmPackages.flatMapTo(mutableSetOf()) { it.npmDependencies }
+        }
+    }
+
+    class NpmPackage(
+        val project: Project,
+        val packageJson: PackageJson,
+        val npmDependencies: Set<NpmDependency>
+    ) {
+        fun savePackageJson(gson: Gson) {
+            NpmProject[project].packageJsonFile.writer().use {
+                gson.toJson(packageJson, it)
+            }
+        }
+    }
+
+    private var packageManagerInstalled = false
+
+    private fun requirePackageManagerSetup() {
+        if (packageManagerInstalled) return
+        packageManager.setup(rootProject)
+        packageManagerInstalled = true
+    }
+
+    private fun resolve(
+        project: Project,
+        parentGradleModules: GradleNodeModules?
+    ): Boolean {
+        val existedProcess = ProjectData[project]
+        if (existedProcess != null) {
+            if (existedProcess.resolved != null) error("yarn dependencies for $project already resolved")
+            else {
+                // called inside resolution of classpath (from visitTarget)
+                // we should return as we are already in progress
+                return false
+            }
+        } else ProjectData().also {
+            ProjectData[project] = it
+        }
+
+        val gradleModules =
+            if (hoistGradleNodeModules && parentGradleModules != null) parentGradleModules
+            else GradleNodeModules(project)
+
+        project.subprojects.forEach {
+            resolve(it, gradleModules)
+        }
+
+        val npmPackage = extractNpmPackage(project, gradleModules)
+        if (npmPackage != null) {
+            npmPackage.savePackageJson(gson)
+
+            requirePackageManagerSetup()
+            packageManager.resolveProject(npmPackage)
+
+            npmPackages.add(npmPackage)
+        }
+
+        if (project == rootProject) {
+            if (npmPackages.isNotEmpty()) {
+                requirePackageManagerSetup()
+                packageManager.resolveRootProject(rootProject, npmPackages)
+            }
+        }
+
+        if (gradleModules != parentGradleModules) {
+            gradleModules.close()
+        }
+
+        return true
+    }
+
+    private fun extractNpmPackage(
+        project: Project,
+        gradleComponents: GradleNodeModules
+    ): NpmPackage? {
+        val packageJson = PackageJson(project.name, project.version.toString())
+        val npmDependencies = mutableSetOf<NpmDependency>()
+
+        visitNpmDependencies(project, npmDependencies, gradleComponents, packageJson)
+
+        if (!hoistGradleNodeModules || project == project.rootProject) {
+            gradleComponents.modules.forEach {
+                val relativePath = it.path.relativeTo(NpmProject[project].nodeWorkDir)
+                packageJson.dependencies[it.name] = "file:$relativePath"
+            }
+        }
+
+        project.nodeJs.packageJsonHandlers.forEach {
+            it(packageJson)
+        }
+
+        val packageJsonRequired = if (project == rootProject) {
+            packageManager.hookRootPackage(rootProject, packageJson, npmPackages)
+        } else false
+
+        return if (packageJsonRequired || !packageJson.empty) NpmPackage(project, packageJson, npmDependencies) else null
+    }
+
+    private fun visitNpmDependencies(
+        project: Project,
+        npmDependencies: MutableSet<NpmDependency>,
+        gradleComponents: GradleNodeModules,
+        packageJson: PackageJson
+    ) {
+        val kotlin = project.kotlinExtensionOrNull
+
+        if (kotlin != null) {
+            when (kotlin) {
+                is KotlinSingleTargetExtension -> visitTarget(kotlin.target, project, npmDependencies, gradleComponents)
+                is KotlinMultiplatformExtension -> kotlin.targets.forEach {
+                    visitTarget(it, project, npmDependencies, gradleComponents)
+                }
+            }
+
+            npmDependencies.forEach {
+                packageJson.dependencies[it.key] = chooseVersion(packageJson.dependencies[it.key], it.version)
+            }
+        }
+    }
+
+    private fun chooseVersion(oldVersion: String?, newVersion: String): String =
+        oldVersion ?: newVersion // todo: real versions conflict resolution
+
+    private fun visitTarget(
+        target: KotlinTarget,
+        project: Project,
+        npmDependencies: MutableSet<NpmDependency>,
+        gradleComponents: GradleNodeModules
+    ) {
+        if (target.platformType == KotlinPlatformType.js) {
+            target.compilations.toList().forEach { compilation ->
+                compilation.relatedConfigurationNames.forEach {
+                    project.configurations.getByName(it).allDependencies.forEach { dependency ->
+                        when (dependency) {
+                            is NpmDependency -> npmDependencies.add(dependency)
+                        }
+                    }
+                }
+
+                gradleComponents.visitCompilation(compilation)
+            }
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+class PackageJson(
+    var name: String,
+    var version: String
+) {
+    val empty: Boolean
+        get() = private == null &&
+                workspaces == null &&
+                dependencies.isEmpty() &&
+                devDependencies.isEmpty()
+
+    val scopedName: ScopedName
+        get() = scopedName(name)
+
+    var private: Boolean? = null
+
+    var main: String? = null
+
+    var workspaces: Collection<String>? = null
+
+    val devDependencies = mutableMapOf<String, String>()
+    val dependencies = mutableMapOf<String, String>()
+
+    companion object {
+        fun scopedName(name: String): ScopedName = if (name.contains("/")) ScopedName(
+            scope = name.substringBeforeLast("/").removePrefix("@"),
+            name = name.substringAfterLast("/")
+        ) else ScopedName(scope = null, name = name)
+
+        operator fun invoke(scope: String, name: String, version: String) =
+            PackageJson(ScopedName(scope, name).toString(), version)
+    }
+
+    data class ScopedName(val scope: String?, val name: String) {
+        override fun toString() = if (scope == null) name else "@$scope/$name"
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/tasks/KotlinJsNodeModulesTask.kt

@@ -52,12 +52,12 @@ open class KotlinJsNodeModulesTask : DefaultTask() {
     }
 }
 
-private val File.isZip
+internal val File.isZip
     get() = isFile && (name.endsWith(".jar") || name.endsWith(".zip"))
 
 internal fun isKotlinJsRuntimeFile(file: File): Boolean {
     if (!file.isFile) return false
     val name = file.name
     return (name.endsWith(".js") && !name.endsWith(".meta.js"))
-        || name.endsWith(".js.map")
+            || name.endsWith(".js.map")
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/KotlinJsTest.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.testing
+
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.SkipWhenEmpty
+import org.gradle.process.internal.DefaultProcessForkOptions
+import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesTestExecutionSpec
+import org.jetbrains.kotlin.gradle.plugin.HasKotlinDependencies
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmProject
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmResolver
+import org.jetbrains.kotlin.gradle.targets.js.testing.karma.KotlinKarma
+import org.jetbrains.kotlin.gradle.targets.js.testing.mocha.KotlinMocha
+import org.jetbrains.kotlin.gradle.targets.js.testing.nodejs.KotlinNodeJsTestRunner
+import org.jetbrains.kotlin.gradle.tasks.KotlinTest
+
+open class KotlinJsTest : KotlinTest() {
+    @Internal
+    @SkipWhenEmpty
+    internal var testFramework: KotlinJsTestFramework? = null
+
+    @Input
+    var debug: Boolean = false
+
+    @Internal
+    var runtimeDependencyHandler: HasKotlinDependencies? = null
+
+    @Input
+    var nodeModulesToLoad: MutableList<String> = mutableListOf()
+
+    fun useNodeJs(body: KotlinNodeJsTestRunner.() -> Unit) = use(KotlinNodeJsTestRunner(), body)
+
+    fun useMocha(body: KotlinMocha.() -> Unit) = use(KotlinMocha(), body)
+
+    fun useKarma(body: KotlinKarma.() -> Unit) = use(KotlinKarma(), body)
+
+    private inline fun <T : KotlinJsTestFramework> use(runner: T, body: T.() -> Unit): T {
+        check(testFramework == null) {
+            "testFramework already configured for task ${this.path}"
+        }
+
+        val testFramework = runner.also(body)
+        this.testFramework = testFramework
+
+        val dependenciesHolder = runtimeDependencyHandler
+        if (dependenciesHolder != null) {
+            testFramework.configure(dependenciesHolder)
+        }
+
+        return testFramework
+    }
+
+    override fun executeTests() {
+        NpmResolver.resolve(project)
+        super.executeTests()
+    }
+
+    override fun createTestExecutionSpec(): TCServiceMessagesTestExecutionSpec {
+        val forkOptions = DefaultProcessForkOptions(fileResolver)
+
+        NpmResolver.resolve(project)
+
+        forkOptions.workingDir = NpmProject[project].nodeWorkDir
+        forkOptions.executable = NodeJsPlugin.apply(project).root.environment.nodeExecutable
+
+        val nodeJsArgs = mutableListOf<String>()
+
+        if (debug) {
+            nodeJsArgs.add("--inspect-brk")
+        }
+
+        return testFramework!!.createTestExecutionSpec(this, forkOptions, nodeJsArgs)
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpack.kt

@@ -0,0 +1,179 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.webpack
+
+import com.google.gson.stream.JsonWriter
+import org.gradle.api.DefaultTask
+import org.gradle.api.internal.file.FileResolver
+import org.gradle.api.tasks.*
+import org.gradle.process.internal.ExecHandleFactory
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationToRunnableFiles
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmProject
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmResolver
+import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
+import org.jetbrains.kotlin.gradle.tasks.Kotlin2JsCompile
+import org.jetbrains.kotlin.gradle.tasks.createOrRegisterTask
+import org.jetbrains.kotlin.gradle.testing.internal.reportsDir
+import org.jetbrains.kotlin.gradle.utils.injected
+import java.io.File
+import java.io.StringWriter
+import javax.inject.Inject
+
+open class KotlinWebpack : DefaultTask() {
+    @get:Inject
+    open val fileResolver: FileResolver
+        get() = injected
+
+    @get:Inject
+    open val execHandleFactory: ExecHandleFactory
+        get() = injected
+
+    @Input
+    @SkipWhenEmpty
+    open lateinit var entry: File
+
+    open val configFile: File
+        @OutputFile get() = project.buildDir.resolve("webpack.config.js")
+
+    @Input
+    var saveConfigFileEffective: Boolean = true
+
+    open val configFileEffective: File
+        @OutputFile get() = project.buildDir.resolve("webpack.config.evaluated.js")
+
+    open val outputPath: File
+        @OutputDirectory get() = project.buildDir.resolve("lib")
+
+    open val configDirectory: File
+        @InputDirectory get() = project.projectDir.resolve("webpack.config.d")
+
+    @Input
+    var report: Boolean = false
+
+    open val reportDir: File
+        @OutputDirectory get() = project.reportsDir.resolve("webpack").resolve(entry.nameWithoutExtension)
+
+    @TaskAction
+    fun execute() {
+        check(entry.isFile) {
+            "${this}: Entry file not existed \"$entry\""
+        }
+
+        NpmResolver.resolve(project)
+
+        val npmProjectLayout = NpmProject[project]
+
+        configFile.writeText(buildConfig())
+
+        val execFactory = execHandleFactory.newExec()
+        npmProjectLayout.useTool(
+            execFactory,
+            ".bin/webpack",
+            "--config", configFile.absolutePath
+        )
+        val exec = execFactory.build()
+        exec.start()
+        exec.waitForFinish()
+    }
+
+    private fun buildConfig(): String {
+        return buildString {
+            //language=JavaScript 1.8
+            append(
+                """ 
+    const config = {
+      mode: 'development',
+      entry: '${entry.canonicalPath}',
+      output: {
+        path: '${outputPath.canonicalPath}',
+        filename: '${entry.name}'
+      },
+      resolve: {
+        modules: [
+          "node_modules"
+        ]
+      },
+      plugins: [],
+      module: {
+        rules: []
+      }
+    };
+                    """
+            )
+
+            if (saveConfigFileEffective) {
+                //language=JavaScript 1.8
+                append(
+                    """
+    const util = require('util');
+    const fs = require("fs");
+    const evaluatedConfig = util.inspect(config, {showHidden: false, depth: null, compact: false});
+    fs.writeFile(${jsQuotedString(configFileEffective.canonicalPath)}, evaluatedConfig, (err) => {});                    
+                        """
+                )
+            }
+
+            if (report) {
+                //language=JavaScript 1.8
+                append(
+                    """
+    const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin; 
+    config.plugins.push(new BundleAnalyzerPlugin({
+            analyzerMode: "static",
+            reportFilename: "${entry.name}.report.html",
+            openAnalyzer: false,
+            generateStatsFile: true,
+            statsFilename: "${entry.name}.stats.json"
+        })
+    )                        
+                        """
+                )
+            }
+
+            loadConfigs(configDirectory)
+
+            append("module.exports = config")
+        }
+    }
+
+    private fun jsQuotedString(str: String) = StringWriter().also {
+        JsonWriter(it).value(str)
+    }.toString()
+
+    private fun StringBuilder.loadConfigs(confDir: File) {
+        if (confDir.isDirectory) confDir
+            .listFiles()
+            ?.toList()
+            ?.filter { it.name.endsWith(".js") }
+            ?.forEach {
+                append(it.readText())
+                appendln()
+                appendln()
+            }
+    }
+
+    companion object {
+        fun configure(compilation: KotlinCompilationToRunnableFiles<*>) {
+            val project = compilation.target.project
+            val npmProject = project.npmProject
+
+            compilation.dependencies {
+                runtimeOnly(npm("webpack", "4.29.6"))
+                runtimeOnly(npm("webpack-cli", "3.3.0"))
+                runtimeOnly(npm("webpack-bundle-analyzer", "3.3.2"))
+            }
+
+            project.createOrRegisterTask<KotlinWebpack>("webpack") {
+                val compileKotlinTask = compilation.compileKotlinTask
+                compileKotlinTask as Kotlin2JsCompile
+
+                it.dependsOn(compileKotlinTask)
+
+                it.entry = npmProject.moduleOutput(compileKotlinTask)
+            }
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/Yarn.kt

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import org.gradle.api.Project
+import org.gradle.api.internal.project.ProjectInternal
+import org.gradle.internal.hash.FileHasher
+import org.jetbrains.kotlin.daemon.common.toHexString
+import org.jetbrains.kotlin.gradle.internal.execWithProgress
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+import org.jetbrains.kotlin.gradle.targets.js.npm.*
+import java.io.File
+
+object Yarn : NpmApi {
+    override fun setup(project: Project) {
+        YarnPlugin.apply(project).executeSetup()
+    }
+
+    val Project.packageJsonHashFile: File
+        get() = buildDir.resolve("package.json.hash")
+
+    fun yarnExec(
+        project: Project,
+        description: String,
+        vararg args: String,
+        npmProject: NpmProject = NpmProject[project]
+    ) {
+        val nodeJsEnv = NodeJsPlugin.apply(project).root.environment
+        val yarnEnv = YarnPlugin.apply(project).environment
+
+        val packageJsonHashFile = project.packageJsonHashFile
+        val packageJsonHash = if (packageJsonHashFile.exists()) packageJsonHashFile.readText() else null
+
+        val hasher = (project as ProjectInternal).services.get(FileHasher::class.java)
+        val hash = hasher.hash(npmProject.packageJsonFile).toByteArray().toHexString()
+
+        if (packageJsonHash == hash) return
+
+        packageJsonHashFile.writeText(hash)
+
+        val nodeWorkDir = npmProject.nodeWorkDir
+
+        project.execWithProgress(description) { exec ->
+            exec.executable = nodeJsEnv.nodeExecutable
+            exec.args = listOf(yarnEnv.home.resolve("bin/yarn.js").absolutePath) + args
+            exec.workingDir = nodeWorkDir
+        }
+    }
+
+    private fun yarnLockReadTransitiveDependencies(
+        nodeWorkDir: File,
+        srcDependenciesList: Collection<NpmDependency>
+    ) {
+        val yarnLock = nodeWorkDir.resolve("yarn.lock")
+        if (yarnLock.isFile) {
+            val byKey = YarnLock.parse(yarnLock).entries.associateBy { it.key }
+            val visited = mutableSetOf<NpmDependency>()
+
+            fun resolveRecursively(src: NpmDependency): NpmDependency {
+                if (src in visited) return src
+                visited.add(src)
+
+                val key = YarnLock.key(src.key, src.version)
+                val deps = byKey[key]
+                if (deps != null) {
+                    src.dependencies.addAll(deps.dependencies.map { dep ->
+                        val scopedName = dep.scopedName
+
+                        resolveRecursively(
+                            NpmDependency(
+                                src.project,
+                                scopedName.scope,
+                                scopedName.name,
+                                dep.version ?: "*"
+                            )
+                        )
+                    })
+                } else {
+                    // todo: [WARN] cannot find $key in yarn.lock
+                }
+
+                return src
+            }
+
+            srcDependenciesList.forEach { src ->
+                resolveRecursively(src)
+            }
+        }
+    }
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    override fun resolveProject(npmPackage: NpmResolver.NpmPackage) {
+        val project = npmPackage.project
+        if (!project.yarn.useWorkspaces) {
+            yarnExec(project, NpmApi.resolveOperationDescription("yarn for ${project.path}"))
+            yarnLockReadTransitiveDependencies(NpmProject[project].nodeWorkDir, npmPackage.npmDependencies)
+        }
+    }
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    override fun hookRootPackage(
+        rootProject: Project,
+        rootPackageJson: PackageJson,
+        allWorkspaces: Collection<NpmResolver.NpmPackage>
+    ): Boolean {
+        if (rootProject.yarn.useWorkspaces) {
+            rootPackageJson.private = true
+            rootPackageJson.workspaces = allWorkspaces
+                .filter { it.project != rootProject }
+                .map { it.project.projectDir.relativeTo(rootProject.rootDir).path }
+
+            return true
+        }
+
+        return false
+    }
+
+    override fun getHoistGradleNodeModules(project: Project): Boolean =
+        project.rootProject.yarn.useWorkspaces
+
+    @Suppress("EXPOSED_PARAMETER_TYPE")
+    override fun resolveRootProject(
+        rootProject: Project,
+        subprojects: MutableList<NpmResolver.NpmPackage>
+    ) {
+        check(rootProject == rootProject.rootProject)
+
+        if (rootProject.yarn.useWorkspaces) {
+            yarnExec(rootProject, NpmApi.resolveOperationDescription("yarn"))
+            yarnLockReadTransitiveDependencies(NpmProject[rootProject].nodeWorkDir, subprojects.flatMap { it.npmDependencies })
+        } else {
+            if (subprojects.any { it.project != rootProject }) {
+                // todo: proofread message
+                rootProject.logger.warn(
+                    "Build contains sub projects with NPM dependencies. " +
+                            "It is recommended to enable yarn workspaces to store common NPM dependencies in root project. " +
+                            "To enable it add this to your root project: \n" +
+                            "nodeJs { manageNodeModules = true } \n" +
+                            "Note: with `manageNodeModules` enabled, your `node_modules` and `package.json` files will be managed by " +
+                            "Gradle, will be overridden during build and should be ignored in VCS."
+                )
+            }
+        }
+    }
+
+    override fun cleanProject(project: Project) {
+        super.cleanProject(project)
+        project.packageJsonHashFile.delete()
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnEnv.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import java.io.File
+
+internal data class YarnEnv(
+    val downloadUrl: String,
+    val home: File
+)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnExtension.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import org.gradle.api.GradleException
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.logging.kotlinInfo
+
+open class YarnExtension(project: Project) {
+    private val gradleHome = project.gradle.gradleUserHomeDir.also {
+        project.logger.kotlinInfo("Storing cached files in $it")
+    }
+
+    var installationDir = gradleHome.resolve("yarn")
+
+    var distBaseUrl = "https://github.com/yarnpkg/yarn/releases/download"
+    var version = "1.15.2"
+
+    var command = "yarn"
+
+    var download = true
+
+    internal fun buildEnv() = YarnEnv(
+        downloadUrl = "$distBaseUrl/v$version/yarn-v$version.tar.gz",
+        home = installationDir.resolve("yarn-v$version")
+    )
+
+    companion object {
+        const val YARN: String = "yarn"
+
+        operator fun get(project: Project): YarnExtension {
+            val extension = project.extensions.findByType(YarnExtension::class.java)
+            if (extension != null)
+                return extension
+
+            val parentProject = project.parent
+            if (parentProject != null)
+                return get(parentProject)
+
+            throw GradleException("YarnExtension is not installed")
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnLock.kt

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license 
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import com.google.gson.stream.JsonReader
+import org.jetbrains.kotlin.gradle.targets.js.npm.PackageJson
+import java.io.File
+import java.io.StringReader
+
+data class YarnLock(val entries: List<Entry>) {
+    data class Entry(
+        val key: String,
+        val version: String?,
+        val resolved: String?,
+        val integrity: String?,
+        val dependencies: List<Dependency>
+    )
+
+    data class Dependency(val key: String, val version: String?) {
+        val scopedName: PackageJson.ScopedName
+            get() = PackageJson.scopedName(key)
+    }
+
+    companion object {
+        fun key(packageKey: String, version: String) = "$packageKey@$version"
+
+        private class Node(val parent: Node?, val value: String? = null) {
+            var indent: String? = null
+            val children = mutableMapOf<String, Node>()
+        }
+
+        fun parse(yarnLock: File): YarnLock {
+            val root = parseTree(yarnLock)
+
+            return YarnLock(root.children.map {
+                val values = it.value.children
+                Entry(
+                    it.key,
+                    values["version"]?.value,
+                    values["resolved"]?.value,
+                    values["integrity"]?.value,
+                    values["dependencies"]?.children?.map { dep ->
+                        Dependency(dep.key, dep.value.value)
+                    } ?: listOf()
+                )
+            })
+        }
+
+        private fun parseTree(yarnLock: File): Node {
+            val root = Node(null)
+            var parent = root
+            var onNewLevel = true
+            yarnLock.useLines {
+                it.forEach { line ->
+                    if (!line.startsWith("#")) {
+                        var i = 0
+                        while (i < line.length && line[i].isWhitespace()) i++
+                        val indentPos = i
+                        val indent = line.substring(0, indentPos)
+
+                        var key = false
+                        val line1: String = if (line.endsWith(":")) {
+                            key = true
+                            line.removeSuffix(":")
+                        } else line
+
+                        if (line1.isNotEmpty()) {
+                            val values = line1.substring(indentPos).split(" ").map { value ->
+                                val value1 = value.removeSuffix(",")
+                                if (value1.startsWith("\""))
+                                    try {
+                                        JsonReader(StringReader(value1)).nextString()
+                                    } catch (e: Throwable) {
+                                        value1.removePrefix("\"").removeSuffix("\"")
+                                    }
+                                else value1
+                            }
+
+                            if (onNewLevel) {
+                                parent.indent = indent
+                                onNewLevel = false
+                            } else {
+                                while (indent != parent.indent!!) {
+                                    parent = parent.parent!!
+                                }
+                            }
+
+                            val child = Node(parent, if (values.size > 1) values[1] else null)
+                            if (key) {
+                                values.forEach {
+                                    parent.children[it] = child
+                                }
+                                parent = child
+                                onNewLevel = true
+                            } else {
+                                parent.children[values[0]] = child
+                            }
+                        }
+                    }
+                }
+            }
+            return root
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnPlugin.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+
+open class YarnPlugin : Plugin<Project> {
+    override fun apply(project: Project): Unit = project.run {
+        check(project == project.rootProject) {
+            "YarnPlugin can be applied only to root project"
+        }
+
+        val nodeJs = NodeJsPlugin.apply(this)
+
+        this.extensions.create(YarnRootExtension.YARN, YarnRootExtension::class.java, this)
+        tasks.create(YarnSetupTask.NAME, YarnSetupTask::class.java) {
+            it.dependsOn(nodeJs.nodeJsSetupTask)
+        }
+    }
+
+    companion object {
+        fun apply(project: Project): YarnRootExtension {
+            val rootProject = project.rootProject
+            rootProject.plugins.apply(YarnPlugin::class.java)
+            return rootProject.extensions.getByName(YarnRootExtension.YARN) as YarnRootExtension
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnRootExtension.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import org.gradle.api.Project
+import org.jetbrains.kotlin.gradle.logging.kotlinInfo
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsPlugin
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.nodeJs
+
+open class YarnRootExtension(val project: Project) {
+    private val gradleHome = project.gradle.gradleUserHomeDir.also {
+        project.logger.kotlinInfo("Storing cached files in $it")
+    }
+
+    var installationDir = gradleHome.resolve("yarn")
+
+    var downloadBaseUrl = "https://github.com/yarnpkg/yarn/releases/download"
+    var version = "1.15.2"
+
+    val yarnSetupTask: YarnSetupTask
+        get() = project.tasks.getByName(YarnSetupTask.NAME) as YarnSetupTask
+
+    var disableWorkspaces: Boolean = false
+
+    val useWorkspaces: Boolean
+        get() = project.nodeJs.root.manageNodeModules && !disableWorkspaces
+
+    internal fun executeSetup() {
+        NodeJsPlugin.apply(project).executeSetup()
+
+        val env = environment
+        if (!env.home.isDirectory) {
+            yarnSetupTask.setup()
+        }
+    }
+
+    internal val environment
+        get() = YarnEnv(
+            downloadUrl = "$downloadBaseUrl/v$version/yarn-v$version.tar.gz",
+            home = installationDir.resolve("yarn-v$version")
+        )
+
+    companion object {
+        const val YARN: String = "yarn"
+
+        operator fun get(project: Project): YarnRootExtension {
+            val rootProject = project.rootProject
+            rootProject.plugins.apply(YarnPlugin::class.java)
+            return rootProject.extensions.getByName(YARN) as YarnRootExtension
+        }
+    }
+}
+
+val Project.yarn: YarnRootExtension
+    get() = YarnRootExtension[this]

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/yarn/YarnSetupTask.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.yarn
+
+import de.undercouch.gradle.tasks.download.DownloadAction
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputDirectory
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
+import java.io.File
+import javax.xml.ws.Action
+
+open class YarnSetupTask : DefaultTask() {
+    private val settings = project.yarn
+    private val env by lazy { settings.environment }
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    val downloadUrl
+        @Input get() = env.downloadUrl
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    val destination: File
+        @OutputDirectory get() = env.home
+
+    init {
+        group = NodeJsRootExtension.NODE_JS
+        description = "Download and install a local yarn version."
+
+        onlyIf {
+            !settings.installationDir.exists()
+        }
+    }
+
+    @Action
+    fun setup() {
+        val dir = temporaryDir
+        val tar = download(dir)
+        extract(tar, destination)
+    }
+
+    private fun download(tar: File): File {
+        val action = DownloadAction(project)
+        action.src(downloadUrl)
+        action.dest(tar)
+        action.execute()
+        return action.outputFiles.singleOrNull() ?: error("Cannot get downloaded file $downloadUrl")
+    }
+
+    private fun extract(archive: File, destination: File) {
+        val dirInTar = archive.name.removeSuffix(".tar.gz") + File.pathSeparator
+        project.copy {
+            it.from(project.tarTree(archive))
+            it.into(destination)
+            it.eachFile { fileCopy ->
+                fileCopy.path = fileCopy.path.removePrefix(dirInTar)
+            }
+        }
+    }
+
+    companion object {
+        const val NAME: String = "yarnSetup"
+    }
+}

libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/GradleNodeModuleBuilderKtTest.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.npm
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+class GradleNodeModuleBuilderKtTest {
+    @Test
+    fun fixSemver() {
+        assertEquals("1.3.0-SNAPSHOT", fixSemver("1.3-SNAPSHOT"))
+        assertEquals("1.2.3-RC1-1234", fixSemver("1.2.3-RC1-1234"))
+    }
+}