[Gradle, JS] First steps for npm dependencies in root

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

@@ -7,13 +7,26 @@ package org.jetbrains.kotlin.gradle.targets.js
 
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.api.plugins.ExtensionAware
 import org.gradle.api.plugins.JavaBasePlugin
+import org.gradle.api.reflect.TypeOf.typeOf
 import org.jetbrains.kotlin.gradle.dsl.KotlinJsProjectExtension
 import org.jetbrains.kotlin.gradle.dsl.kotlinExtension
 import org.jetbrains.kotlin.gradle.plugin.configureDefaultVersionsResolutionStrategy
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsSingleTargetPreset
+import org.jetbrains.kotlin.gradle.targets.js.npm.NpmDependency
 import org.jetbrains.kotlin.gradle.utils.checkGradleCompatibility
 
+interface Npm : (String) -> NpmDependency
+
+fun Npm(lambda: (name: String) -> NpmDependency): Npm {
+    return object : Npm {
+        override fun invoke(name: String): NpmDependency {
+            return lambda(name)
+        }
+    }
+}
+
 open class KotlinJsPlugin(
     private val kotlinPluginVersion: String
 ) : Plugin<Project> {
@@ -26,6 +39,16 @@ open class KotlinJsPlugin(
 
         checkGradleCompatibility()
 
+        val npm = Npm { name: String -> NpmDependency(project, null, name, "*") }
+
+        (project.dependencies as ExtensionAware)
+            .extensions
+            .add(
+                typeOf<Npm>(npm::class.java),
+                "npm",
+                npm
+            )
+
         val kotlinExtension = project.kotlinExtension as KotlinJsProjectExtension
         configureDefaultVersionsResolutionStrategy(project, kotlinPluginVersion)