diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmProject.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmProject.kt
index 79fa42de9e2..c6d70477d94 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmProject.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/NpmProject.kt
@@ -128,8 +128,8 @@ open class NpmProject(@Transient val compilation: KotlinJsCompilation) : Seriali
         val rootProjectName = project.rootProject.name
 
         val localName = if (project != project.rootProject) {
-            project.name
-        } else null
+            (rootProjectName + project.path).replace(":", "-")
+        } else rootProjectName
 
         val targetName = if (target.name.isNotEmpty() && target.name.toLowerCaseAsciiOnly() != "js") {
             target.name
@@ -142,7 +142,6 @@ open class NpmProject(@Transient val compilation: KotlinJsCompilation) : Seriali
         } else null
 
         return sequenceOf(
-            rootProjectName,
             localName,
             targetName,
             compilationName
diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
index af543f40ec8..aed9eb7853c 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
@@ -93,15 +93,7 @@ class PackageJson(
             .setPrettyPrinting()
             .disableHtmlEscaping()
             .serializeNulls()
-            .addSerializationExclusionStrategy(
-                object : ExclusionStrategy {
-                    override fun shouldSkipField(f: FieldAttributes?): Boolean =
-                        f?.name == this@PackageJson::customFields.name
-
-                    override fun shouldSkipClass(clazz: Class<*>?): Boolean =
-                        false
-                }
-            )
+            .registerTypeAdapterFactory(PackageJsonTypeAdapter())
             .create()
 
         packageJsonFile.ensureParentDirsCreated()
@@ -112,11 +104,6 @@ class PackageJson(
             }
         } else null
 
-        customFields
-            .forEach { (key, value) ->
-                val valueElement = gson.toJsonTree(value)
-                jsonTree.asJsonObject.add(key, valueElement)
-            }
         if (jsonTree != previous) {
             packageJsonFile.writer().use {
                 gson.toJson(jsonTree, it)
diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJsonTypeAdapter.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJsonTypeAdapter.kt
new file mode 100644
index 00000000000..f79c21157ea
--- /dev/null
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJsonTypeAdapter.kt
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2010-2023 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.npm
+
+import com.google.gson.*
+import com.google.gson.annotations.SerializedName
+import com.google.gson.reflect.TypeToken
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+import java.lang.reflect.Field
+
+// Necessary to get rid of all fields with null value (private, workspace etc)
+// But we need to leave customFields because it is user's null value and it is ok
+// Here we remove all null-valuable fields, read customFields, add them to jsonObject as elements and remove customFields field
+// It helps to not get such json
+// { name: "foo", private: null, customFields: { customField1: null }, customField1: null }
+// but just
+// { name: "foo", customField1: "foo" }
+class PackageJsonTypeAdapter : TypeAdapterFactory {
+
+    override fun <T : Any?> create(gson: Gson, type: TypeToken<T>): TypeAdapter<T>? {
+
+        if (type.rawType != PackageJson::class.java) return null
+
+        fun Field.serializedName() = declaredAnnotations
+            .filterIsInstance<SerializedName>()
+            .firstOrNull()?.value ?: name
+
+        val declaredFields = type.rawType.declaredFields
+
+        val customFieldsField = declaredFields
+            .single { it.name == PackageJson::customFields.name }
+
+        return object : TypeAdapter<T>() {
+            private val delegateAdapter = gson.getDelegateAdapter(this@PackageJsonTypeAdapter, type)
+            private val elementAdapter = gson.getAdapter(JsonElement::class.java)
+
+            override fun write(writer: JsonWriter, value: T?) {
+                val jsonObject = delegateAdapter.toJsonTree(value).asJsonObject
+
+                customFieldsField.isAccessible = true
+                val customFields = customFieldsField.get(value) as Map<*, *>
+
+                customFields
+                    .forEach { (key, value) ->
+                        val valueElement = gson.toJsonTree(value)
+                        key as String
+                        jsonObject.add(key, valueElement)
+                    }
+
+                declaredFields
+                    .map { it.serializedName() }
+                    .filter { jsonObject.get(it) is JsonNull }
+                    .forEach { jsonObject.remove(it) }
+
+                jsonObject.remove(customFieldsField.serializedName())
+
+                val originalSerializeNulls = writer.serializeNulls
+                writer.serializeNulls = true
+                elementAdapter.write(writer, jsonObject)
+                writer.serializeNulls = originalSerializeNulls
+            }
+
+            override fun read(reader: JsonReader): T {
+                return delegateAdapter.read(reader)
+            }
+        }
+    }
+}
\ No newline at end of file