diff --git a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml b/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
deleted file mode 100644
index 603abbe..0000000
--- a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<component name="libraryTable">
-  <library name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" type="kotlin.js">
-    <CLASSES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/a9af9a599001f2c99a030b86fcb050e27f7d30d6/kotlin-stdlib-js-1.1.51.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/eebb8733b5f54e7685b35ff45da6c5f62785012d/kotlin-stdlib-js-1.1.51-sources.jar!/" />
-    </SOURCES>
-  </library>
-</component>
\ No newline at end of file

diff --git a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml b/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
deleted file mode 100644
index 603abbe..0000000
--- a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<component name="libraryTable">
-  <library name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" type="kotlin.js">
-    <CLASSES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/a9af9a599001f2c99a030b86fcb050e27f7d30d6/kotlin-stdlib-js-1.1.51.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/eebb8733b5f54e7685b35ff45da6c5f62785012d/kotlin-stdlib-js-1.1.51-sources.jar!/" />
-    </SOURCES>
-  </library>
-</component>
\ No newline at end of file
diff --git a/.idea/modules/kudens_main.iml b/.idea/modules/kudens_main.iml
index a0a18a1..1ecd401 100644
--- a/.idea/modules/kudens_main.iml
+++ b/.idea/modules/kudens_main.iml
@@ -3,6 +3,7 @@
   <component name="FacetManager">
     <facet type="kotlin-language" name="Kotlin">
       <configuration version="2" platform="JavaScript " useProjectSettings="false">
+        <testOutputPath>$MODULE_DIR$/../../build/classes/kotlin/test/kudens_test.js</testOutputPath>
         <compilerSettings>
           <option name="additionalArguments" value="-verbose" />
         </compilerSettings>
@@ -10,12 +11,11 @@
           <option name="outputFile" value="$MODULE_DIR$/../../build/kotlinjs/kudens.js" />
           <option name="noStdlib" value="true" />
           <option name="sourceMap" value="true" />
-          <option name="sourceMapEmbedSources" value="inlining" />
           <option name="metaInfo" value="true" />
           <option name="target" value="v5" />
           <option name="main" value="call" />
-          <option name="languageVersion" value="1.1" />
-          <option name="apiVersion" value="1.1" />
+          <option name="languageVersion" value="1.2" />
+          <option name="apiVersion" value="1.2" />
           <option name="pluginOptions">
             <array />
           </option>
@@ -32,12 +32,11 @@
     <output url="file://$MODULE_DIR$/../../out/production/classes" />
     <exclude-output />
     <content url="file://$MODULE_DIR$/../../src/main">
-      <sourceFolder url="file://$MODULE_DIR$/../../src/main/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/kotlin" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/resources" type="java-resource" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" level="project" />
+    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.2.21" level="project" />
   </component>
 </module>
\ No newline at end of file

diff --git a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml b/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
deleted file mode 100644
index 603abbe..0000000
--- a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<component name="libraryTable">
-  <library name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" type="kotlin.js">
-    <CLASSES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/a9af9a599001f2c99a030b86fcb050e27f7d30d6/kotlin-stdlib-js-1.1.51.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/eebb8733b5f54e7685b35ff45da6c5f62785012d/kotlin-stdlib-js-1.1.51-sources.jar!/" />
-    </SOURCES>
-  </library>
-</component>
\ No newline at end of file
diff --git a/.idea/modules/kudens_main.iml b/.idea/modules/kudens_main.iml
index a0a18a1..1ecd401 100644
--- a/.idea/modules/kudens_main.iml
+++ b/.idea/modules/kudens_main.iml
@@ -3,6 +3,7 @@
   <component name="FacetManager">
     <facet type="kotlin-language" name="Kotlin">
       <configuration version="2" platform="JavaScript " useProjectSettings="false">
+        <testOutputPath>$MODULE_DIR$/../../build/classes/kotlin/test/kudens_test.js</testOutputPath>
         <compilerSettings>
           <option name="additionalArguments" value="-verbose" />
         </compilerSettings>
@@ -10,12 +11,11 @@
           <option name="outputFile" value="$MODULE_DIR$/../../build/kotlinjs/kudens.js" />
           <option name="noStdlib" value="true" />
           <option name="sourceMap" value="true" />
-          <option name="sourceMapEmbedSources" value="inlining" />
           <option name="metaInfo" value="true" />
           <option name="target" value="v5" />
           <option name="main" value="call" />
-          <option name="languageVersion" value="1.1" />
-          <option name="apiVersion" value="1.1" />
+          <option name="languageVersion" value="1.2" />
+          <option name="apiVersion" value="1.2" />
           <option name="pluginOptions">
             <array />
           </option>
@@ -32,12 +32,11 @@
     <output url="file://$MODULE_DIR$/../../out/production/classes" />
     <exclude-output />
     <content url="file://$MODULE_DIR$/../../src/main">
-      <sourceFolder url="file://$MODULE_DIR$/../../src/main/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/kotlin" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/resources" type="java-resource" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" level="project" />
+    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.2.21" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/.idea/modules/kudens_test.iml b/.idea/modules/kudens_test.iml
index 35efbcf..43edcc2 100644
--- a/.idea/modules/kudens_test.iml
+++ b/.idea/modules/kudens_test.iml
@@ -7,12 +7,11 @@
         <compilerArguments>
           <option name="outputFile" value="$MODULE_DIR$/../../build/classes/kotlin/test/kudens_test.js" />
           <option name="noStdlib" value="true" />
-          <option name="sourceMapEmbedSources" value="inlining" />
           <option name="metaInfo" value="true" />
           <option name="target" value="v5" />
           <option name="main" value="call" />
-          <option name="languageVersion" value="1.1" />
-          <option name="apiVersion" value="1.1" />
+          <option name="languageVersion" value="1.2" />
+          <option name="apiVersion" value="1.2" />
           <option name="pluginOptions">
             <array />
           </option>
@@ -28,14 +27,13 @@
     <output-test url="file://$MODULE_DIR$/../../out/test/classes" />
     <exclude-output />
     <content url="file://$MODULE_DIR$/../../src/test">
-      <sourceFolder url="file://$MODULE_DIR$/../../src/test/java" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/test/kotlin" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/test/resources" type="java-test-resource" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="module" module-name="kudens_main" />
-    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" level="project" />
+    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.2.21" level="project" />
   </component>
   <component name="TestModuleProperties" production-module="kudens_main" />
 </module>
\ No newline at end of file

diff --git a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml b/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
deleted file mode 100644
index 603abbe..0000000
--- a/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_js_1_1_51.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<component name="libraryTable">
-  <library name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" type="kotlin.js">
-    <CLASSES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/a9af9a599001f2c99a030b86fcb050e27f7d30d6/kotlin-stdlib-js-1.1.51.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES>
-      <root url="jar://$USER_HOME$/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-js/1.1.51/eebb8733b5f54e7685b35ff45da6c5f62785012d/kotlin-stdlib-js-1.1.51-sources.jar!/" />
-    </SOURCES>
-  </library>
-</component>
\ No newline at end of file
diff --git a/.idea/modules/kudens_main.iml b/.idea/modules/kudens_main.iml
index a0a18a1..1ecd401 100644
--- a/.idea/modules/kudens_main.iml
+++ b/.idea/modules/kudens_main.iml
@@ -3,6 +3,7 @@
   <component name="FacetManager">
     <facet type="kotlin-language" name="Kotlin">
       <configuration version="2" platform="JavaScript " useProjectSettings="false">
+        <testOutputPath>$MODULE_DIR$/../../build/classes/kotlin/test/kudens_test.js</testOutputPath>
         <compilerSettings>
           <option name="additionalArguments" value="-verbose" />
         </compilerSettings>
@@ -10,12 +11,11 @@
           <option name="outputFile" value="$MODULE_DIR$/../../build/kotlinjs/kudens.js" />
           <option name="noStdlib" value="true" />
           <option name="sourceMap" value="true" />
-          <option name="sourceMapEmbedSources" value="inlining" />
           <option name="metaInfo" value="true" />
           <option name="target" value="v5" />
           <option name="main" value="call" />
-          <option name="languageVersion" value="1.1" />
-          <option name="apiVersion" value="1.1" />
+          <option name="languageVersion" value="1.2" />
+          <option name="apiVersion" value="1.2" />
           <option name="pluginOptions">
             <array />
           </option>
@@ -32,12 +32,11 @@
     <output url="file://$MODULE_DIR$/../../out/production/classes" />
     <exclude-output />
     <content url="file://$MODULE_DIR$/../../src/main">
-      <sourceFolder url="file://$MODULE_DIR$/../../src/main/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/kotlin" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/main/resources" type="java-resource" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
-    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" level="project" />
+    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.2.21" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/.idea/modules/kudens_test.iml b/.idea/modules/kudens_test.iml
index 35efbcf..43edcc2 100644
--- a/.idea/modules/kudens_test.iml
+++ b/.idea/modules/kudens_test.iml
@@ -7,12 +7,11 @@
         <compilerArguments>
           <option name="outputFile" value="$MODULE_DIR$/../../build/classes/kotlin/test/kudens_test.js" />
           <option name="noStdlib" value="true" />
-          <option name="sourceMapEmbedSources" value="inlining" />
           <option name="metaInfo" value="true" />
           <option name="target" value="v5" />
           <option name="main" value="call" />
-          <option name="languageVersion" value="1.1" />
-          <option name="apiVersion" value="1.1" />
+          <option name="languageVersion" value="1.2" />
+          <option name="apiVersion" value="1.2" />
           <option name="pluginOptions">
             <array />
           </option>
@@ -28,14 +27,13 @@
     <output-test url="file://$MODULE_DIR$/../../out/test/classes" />
     <exclude-output />
     <content url="file://$MODULE_DIR$/../../src/test">
-      <sourceFolder url="file://$MODULE_DIR$/../../src/test/java" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/test/kotlin" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/../../src/test/resources" type="java-test-resource" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="module" module-name="kudens_main" />
-    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.1.51" level="project" />
+    <orderEntry type="library" name="Gradle: org.jetbrains.kotlin:kotlin-stdlib-js:1.2.21" level="project" />
   </component>
   <component name="TestModuleProperties" production-module="kudens_main" />
 </module>
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index a06c872..7ae9969 100644
--- a/build.gradle
+++ b/build.gradle
@@ -20,7 +20,7 @@
 }
 
 buildscript {
-    ext.kotlin_version = '1.1.60'
+    ext.kotlin_version = '1.2.21'
     repositories {
         maven {
             url "http://nexus.astraeus.nl/nexus/content/groups/public"