diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsCompilation.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsCompilation.kt
index 082079f2f97..d8dca27d0a1 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsCompilation.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsCompilation.kt
@@ -8,7 +8,9 @@
 // Old package for compatibility
 package org.jetbrains.kotlin.gradle.plugin.mpp
 
+import groovy.lang.Closure
 import org.gradle.api.tasks.TaskProvider
+import org.gradle.util.ConfigureUtil
 import org.gradle.util.WrapUtil
 import org.jetbrains.kotlin.gradle.dsl.KotlinJsOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinJsOptionsImpl
@@ -60,11 +62,16 @@ open class KotlinJsCompilation(
 
     internal val packageJsonHandlers = mutableListOf<PackageJson.() -> Unit>()
 
-    @Suppress("unused")
     fun packageJson(handler: PackageJson.() -> Unit) {
         packageJsonHandlers.add(handler)
     }
 
+    fun packageJson(handler: Closure<*>) {
+        packageJson {
+            ConfigureUtil.configure(handler, this)
+        }
+    }
+
     override val apiConfigurationName: String
         get() = disambiguateNameInPlatform(API)
 
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
index a25e6642198..a5ef81c16cd 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PackageJson.kt
@@ -10,6 +10,7 @@ import com.google.gson.FieldAttributes
 import com.google.gson.Gson
 import com.google.gson.GsonBuilder
 import org.gradle.api.GradleException
+import org.gradle.api.tasks.Input
 import org.jetbrains.kotlin.gradle.internal.ensureParentDirsCreated
 import java.io.File
 
@@ -18,7 +19,7 @@ class PackageJson(
     var name: String,
     var version: String
 ) {
-    private val customFields = mutableMapOf<String, Any>()
+    internal val customFields = mutableMapOf<String, Any?>()
 
     val empty: Boolean
         get() = main == null &&
@@ -60,10 +61,22 @@ class PackageJson(
     val bundledDependencies = mutableListOf<String>()
         get() = field ?: mutableListOf()
 
+    fun customField(pair: Pair<String, Any>) {
+        customFields[pair.first] = pair.second
+    }
+
     fun customField(key: String, value: Any) {
         customFields[key] = value
     }
 
+    fun customField(key: String, value: Number) {
+        customFields[key] = value
+    }
+
+    fun customField(key: String, value: Boolean) {
+        customFields[key] = value
+    }
+
     companion object {
         fun scopedName(name: String): ScopedName = if (name.contains("/")) ScopedName(
             scope = name.substringBeforeLast("/").removePrefix("@"),
@@ -163,4 +176,6 @@ private fun chooseVersion(
                 There is already declared version of '$module' with version '$oldVersion' which does not intersects with another declared version '${newVersion}'
             """.trimIndent()
         )
-}
\ No newline at end of file
+}
+
+internal const val fakePackageJsonValue = "FAKE"
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PublicPackageJsonTask.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PublicPackageJsonTask.kt
index 7939e1368a4..2c8427a2b82 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PublicPackageJsonTask.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/PublicPackageJsonTask.kt
@@ -21,7 +21,7 @@ import javax.inject.Inject
 open class PublicPackageJsonTask
 @Inject
 constructor(
-    compilation: KotlinJsCompilation
+    private val compilation: KotlinJsCompilation
 ) : DefaultTask() {
 
     private val npmProject = compilation.npmProject
@@ -31,6 +31,13 @@ constructor(
     private val compilationResolution
         get() = nodeJs.npmResolutionManager.requireInstalled()[project][npmProject.compilation]
 
+    @get:Input
+    val packageJsonCustomFields: Map<String, Any?>
+        get() = PackageJson(fakePackageJsonValue, fakePackageJsonValue)
+            .apply {
+                compilation.packageJsonHandlers.forEach { it() }
+            }.customFields
+
     @get:Nested
     internal val externalDependencies: Collection<NestedNpmDependency>
         get() = compilationResolution.externalNpmDependencies
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/tasks/KotlinPackageJsonTask.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/tasks/KotlinPackageJsonTask.kt
index 906edacf1c0..69fb8dd2c1c 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/tasks/KotlinPackageJsonTask.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/npm/tasks/KotlinPackageJsonTask.kt
@@ -11,6 +11,8 @@ import org.gradle.api.tasks.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
 import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
 import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
+import org.jetbrains.kotlin.gradle.targets.js.npm.PackageJson
+import org.jetbrains.kotlin.gradle.targets.js.npm.fakePackageJsonValue
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
 import org.jetbrains.kotlin.gradle.targets.js.npm.resolver.KotlinCompilationNpmResolver
 import org.jetbrains.kotlin.gradle.targets.js.npm.resolver.PACKAGE_JSON_UMBRELLA_TASK_NAME
@@ -28,6 +30,13 @@ open class KotlinPackageJsonTask : DefaultTask() {
     private val producer: KotlinCompilationNpmResolver.PackageJsonProducer
         get() = compilationResolver.packageJsonProducer
 
+    @get:Input
+    val packageJsonCustomFields: Map<String, Any?>
+        get() = PackageJson(fakePackageJsonValue, fakePackageJsonValue)
+            .apply {
+                compilation.packageJsonHandlers.forEach { it() }
+            }.customFields
+
     private fun findDependentTasks(): Collection<Any> =
         producer.internalDependencies.map { dependentResolver ->
             dependentResolver.npmProject.packageJsonTask