diff --git a/compiler/util/src/org/jetbrains/kotlin/utils/KotlinJavascriptMetadataUtils.kt b/compiler/util/src/org/jetbrains/kotlin/utils/KotlinJavascriptMetadataUtils.kt
index 02fe219af5b..271a0e0fcd1 100644
--- a/compiler/util/src/org/jetbrains/kotlin/utils/KotlinJavascriptMetadataUtils.kt
+++ b/compiler/util/src/org/jetbrains/kotlin/utils/KotlinJavascriptMetadataUtils.kt
@@ -41,10 +41,12 @@ public object KotlinJavascriptMetadataUtils {
     public fun hasMetadata(text: String): Boolean = METADATA_PATTERN.matcher(text).find()
 
     public fun writeMetadata(moduleName: String, content: ByteArray, metaFile: File) {
-        val text = "// Kotlin.$KOTLIN_JAVASCRIPT_METHOD_NAME($ABI_VERSION, \"$moduleName\", \"${printBase64Binary(content)}\");\n"
-        FileUtil.writeToFile(metaFile, text)
+        FileUtil.writeToFile(metaFile, writeMetadataToString(moduleName, content))
     }
 
+    public fun writeMetadataToString(moduleName: String, content: ByteArray): String =
+        "// Kotlin.$KOTLIN_JAVASCRIPT_METHOD_NAME($ABI_VERSION, \"$moduleName\", \"${printBase64Binary(content)}\");\n"
+
     platformStatic
     public fun loadMetadata(file: File): List<KotlinJavascriptMetadata> {
         assert(file.exists()) { "Library " + file + " not found" }
diff --git a/js/js.serializer/src/org/jetbrains/kotlin/utils/serializer/KotlinJavaScriptSerializer.kt b/js/js.serializer/src/org/jetbrains/kotlin/utils/serializer/KotlinJavaScriptSerializer.kt
index 45dc3f52da8..0da4f38cd9d 100644
--- a/js/js.serializer/src/org/jetbrains/kotlin/utils/serializer/KotlinJavaScriptSerializer.kt
+++ b/js/js.serializer/src/org/jetbrains/kotlin/utils/serializer/KotlinJavaScriptSerializer.kt
@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.utils.serializer
 
+import com.intellij.openapi.util.io.FileUtil
 import org.jetbrains.kotlin.builtins.BuiltInsSerializationUtil
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
@@ -36,6 +37,10 @@ import java.io.File
 public class KotlinJavaScriptSerializer() {
 
     public fun serialize(moduleName: String, moduleDescriptor: ModuleDescriptor, metaFile: File) {
+        FileUtil.writeToFile(metaFile, serializeToString(moduleName, moduleDescriptor))
+    }
+
+    public fun serializeToString(moduleName: String, moduleDescriptor: ModuleDescriptor): String {
         val contentMap = hashMapOf<String, ByteArray>()
 
         DescriptorUtils.getPackagesFqNames(moduleDescriptor).forEach {
@@ -47,7 +52,7 @@ public class KotlinJavaScriptSerializer() {
         }
 
         val content = KotlinJavascriptSerializationUtil.contentMapToByteArray(contentMap)
-        KotlinJavascriptMetadataUtils.writeMetadata(moduleName, content, metaFile)
+        return KotlinJavascriptMetadataUtils.writeMetadataToString(moduleName, content)
     }
 
     fun serializePackage(module: ModuleDescriptor, fqName: FqName, writeFun: (String, ByteArrayOutputStream) -> Unit) {