diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
index 082a9e5b12a..f918db56628 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
@@ -24,7 +24,6 @@ import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
 import org.jetbrains.kotlin.gradle.targets.js.testing.*
 import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig
-import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig.Devtool
 import org.jetbrains.kotlin.gradle.testing.internal.reportsDir
 import org.slf4j.Logger
 import java.io.File
@@ -150,7 +149,7 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
         val webpackConfigWriter = KotlinWebpackConfig(
             configDirectory = project.projectDir.resolve("webpack.config.d").takeIf { it.isDirectory },
             sourceMaps = true,
-            devtool = Devtool.INLINE_SOURCE_MAP,
+            devtool = null,
             export = false,
             progressReporter = true,
             progressReporterPathFilter = nodeJs.rootPackageDir.absolutePath
@@ -164,6 +163,17 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
             it.appendln("function createWebpackConfig() {")
 
             webpackConfigWriter.appendTo(it)
+            //language=ES6
+            it.appendln(
+                """
+                (function() {
+                    const webpack = require('webpack');
+                    config.plugins.push(new webpack.SourceMapDevToolPlugin({
+                        moduleFilenameTemplate: "[absolute-resource-path]"
+                    }))
+                })();
+            """.trimIndent()
+            )
 
             it.appendln("   return config;")
             it.appendln("}")
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpackConfig.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpackConfig.kt
index 56b105422de..74553b06e90 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpackConfig.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/webpack/KotlinWebpackConfig.kt
@@ -26,7 +26,7 @@ data class KotlinWebpackConfig(
     val bundleAnalyzerReportDir: File? = null,
     val reportEvaluatedConfigFile: File? = null,
     val devServer: DevServer? = null,
-    val devtool: Devtool = Devtool.EVAL_SOURCE_MAP,
+    val devtool: Devtool? = Devtool.EVAL_SOURCE_MAP,
     val showProgress: Boolean = false,
     val sourceMaps: Boolean = false,
     val export: Boolean = true,
@@ -79,8 +79,7 @@ data class KotlinWebpackConfig(
 
     enum class Devtool(val code: String) {
         EVAL_SOURCE_MAP("eval-source-map"),
-        SOURCE_MAP("source-map"),
-        INLINE_SOURCE_MAP("inline-source-map")
+        SOURCE_MAP("source-map")
     }
 
     fun save(configFile: File) {
@@ -197,7 +196,7 @@ data class KotlinWebpackConfig(
                         use: ["kotlin-source-map-loader"],
                         enforce: "pre"
                 });
-                config.devtool = '${devtool.code}';
+                config.devtool = ${devtool?.code?.let { "'$it'" } ?: false};
                 
             """.trimIndent()
         )
diff --git a/libraries/tools/kotlin-test-js-runner/karma-kotlin-reporter.js b/libraries/tools/kotlin-test-js-runner/karma-kotlin-reporter.js
index d98389ee87c..e5ef41dddc8 100644
--- a/libraries/tools/kotlin-test-js-runner/karma-kotlin-reporter.js
+++ b/libraries/tools/kotlin-test-js-runner/karma-kotlin-reporter.js
@@ -1,38 +1,11 @@
-/*
- * Copyright 2010-2019 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.
- */
-
 const util = require('util');
-const resolve = require('url').resolve;
-
-const escapeMessage = function (message) {
-    if (message === null || message === undefined) {
-        return ''
-    }
-
-    return message.toString()
-        .replace(/\|/g, '||')
-        .replace(/'/g, "|'")
-        .replace(/\n/g, '|n')
-        .replace(/\r/g, '|r')
-        .replace(/\u0085/g, '|x')
-        .replace(/\u2028/g, '|l')
-        .replace(/\u2029/g, '|p')
-        .replace(/\[/g, '|[')
-        .replace(/]/g, '|]')
-};
-
-const formatMessage = function () {
-    const args = Array.prototype.slice.call(arguments);
-
-    for (let i = args.length - 1; i > 0; i--) {
-        args[i] = escapeMessage(args[i])
-    }
-
-    return util.format.apply(null, args) + '\n'
-};
+const resolve = require('path').resolve;
 
+/**
+ * From karma
+ * The MIT License
+ * Copyright (C) 2011-2019 Google, Inc.
+ */
 // This ErrorFormatter is copied from standard karma's,
 //  but without warning in case of failed original location finding
 function createFormatError(config, emitter) {
@@ -94,6 +67,38 @@ function createFormatError(config, emitter) {
     };
 }
 
+/**
+ * From karma-teamcity-reporter.
+ * The MIT License
+ * Copyright (C) 2011-2013 Vojta Jína and contributors
+ */
+const escapeMessage = function (message) {
+    if (message === null || message === undefined) {
+        return ''
+    }
+
+    return message.toString()
+        .replace(/\|/g, '||')
+        .replace(/'/g, "|'")
+        .replace(/\n/g, '|n')
+        .replace(/\r/g, '|r')
+        .replace(/\u0085/g, '|x')
+        .replace(/\u2028/g, '|l')
+        .replace(/\u2029/g, '|p')
+        .replace(/\[/g, '|[')
+        .replace(/]/g, '|]')
+};
+
+const formatMessage = function () {
+    const args = Array.prototype.slice.call(arguments);
+
+    for (let i = args.length - 1; i > 0; i--) {
+        args[i] = escapeMessage(args[i])
+    }
+
+    return util.format.apply(null, args) + '\n'
+};
+
 // This reporter extends karma-teamcity-reporter
 //  It is necessary, because karma-teamcity-reporter can't write browser's log
 //  And additionally it overrides flushLogs, because flushLogs adds redundant spaces after some messages