[Gradle, JS]Add optionalNpm methods

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

@@ -71,6 +71,12 @@ interface KotlinDependencyHandler {
 
     fun devNpm(directory: File): Dependency
 
+    fun optionalNpm(name: String, version: String = "*"): Dependency
+
+    fun optionalNpm(name: String, directory: File): Dependency
+
+    fun optionalNpm(directory: File): Dependency
+
     fun peerNpm(name: String, version: String = "*"): Dependency
 }
 

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

@@ -118,6 +118,23 @@ class DefaultKotlinDependencyHandler(
             directory = directory
         )
 
+    override fun optionalNpm(name: String, version: String): NpmDependency =
+        NpmDependency(
+            project = project,
+            name = name,
+            version = version,
+            scope = NpmDependency.Scope.OPTIONAL
+        )
+
+    override fun optionalNpm(name: String, directory: File): NpmDependency =
+        directoryNpmDependency(name, directory, NpmDependency.Scope.OPTIONAL)
+
+    override fun optionalNpm(directory: File): NpmDependency =
+        optionalNpm(
+            name = moduleName(directory),
+            directory = directory
+        )
+
     override fun peerNpm(name: String, version: String): NpmDependency =
         NpmDependency(
             project = project,