diff --git a/js/js.translator/testData/maps.js b/js/js.translator/testData/maps.js
index 61e02737d8c..36e78202ff7 100644
--- a/js/js.translator/testData/maps.js
+++ b/js/js.translator/testData/maps.js
@@ -68,6 +68,8 @@
                         };
 
     function hashObject(obj) {
+        if (obj == null) return "";
+
         var hashCode;
         if (typeof obj == "string") {
             return obj;
@@ -97,23 +99,11 @@
     }
 
     function equals_fixedValueNoEquals(fixedValue, variableValue) {
-        return (typeof variableValue.equals_za3rmp$ == FUNCTION) ?
+        return (variableValue != null && typeof variableValue.equals_za3rmp$ == FUNCTION) ?
+               // TODO: test this case
                variableValue.equals_za3rmp$(fixedValue) : (fixedValue === variableValue);
     }
 
-    function createKeyValCheck(kvStr) {
-        return function (kv) {
-            if (kv === null) {
-                throw new Error("null is not a valid " + kvStr);
-            }
-            else if (typeof kv == "undefined") {
-                throw new Error(kvStr + " must not be undefined");
-            }
-        };
-    }
-
-    var checkKey = createKeyValCheck("key"), checkValue = createKeyValCheck("value");
-
     /**
      * @constructor
      * @param {string} hash
@@ -167,7 +157,7 @@
 
     Bucket.prototype = {
         getEqualityFunction: function (searchValue) {
-            return (typeof searchValue.equals_za3rmp$ == FUNCTION) ? equals_fixedValueHasEquals : equals_fixedValueNoEquals;
+            return (searchValue != null && typeof searchValue.equals_za3rmp$ == FUNCTION) ? equals_fixedValueHasEquals : equals_fixedValueNoEquals;
         },
 
         getEntryForKey: createBucketSearcher(ENTRY),
@@ -178,7 +168,7 @@
             var result = this.getEntryAndIndexForKey(key);
             if (result) {
                 arrayRemoveAt(this.entries, result[0]);
-                return result[1];
+                return result;
             }
             return null;
         },
@@ -253,8 +243,6 @@
         var equalityFunction = (typeof equalityFunctionParam == FUNCTION) ? equalityFunctionParam : null;
 
         this.put_wn2jw4$ = function (key, value) {
-            checkKey(key);
-            checkValue(value);
             var hash = hashingFunction(key), bucket, bucketEntry, oldValue = null;
 
             // Check if a bucket exists for the bucket key
@@ -282,8 +270,6 @@
         };
 
         this.get_za3rmp$ = function (key) {
-            checkKey(key);
-
             var hash = hashingFunction(key);
 
             // Check if a bucket exists for the bucket key
@@ -300,7 +286,6 @@
         };
 
         this.containsKey_za3rmp$ = function (key) {
-            checkKey(key);
             var bucketKey = hashingFunction(key);
 
             // Check if a bucket exists for the bucket key
@@ -310,7 +295,6 @@
         };
 
         this.containsValue_za3rmp$ = function (value) {
-            checkValue(value);
             var i = buckets.length;
             while (i--) {
                 if (buckets[i].containsValue_za3rmp$(value)) {
@@ -354,17 +338,17 @@
         };
 
         this.remove_za3rmp$ = function (key) {
-            checkKey(key);
-
-            var hash = hashingFunction(key), bucketIndex, oldValue = null;
+            var hash = hashingFunction(key), bucketIndex, oldValue = null, result = null;
 
             // Check if a bucket exists for the bucket key
             var bucket = getBucketForHash(bucketsByHash, hash);
 
             if (bucket) {
                 // Remove entry from this bucket for this key
-                oldValue = bucket.removeEntryForKey(key);
-                if (oldValue !== null) {
+                result = bucket.removeEntryForKey(key);
+                if (result !== null) {
+                    oldValue = result[1];
+
                     // Entry was removed, so check if bucket is empty
                     if (!bucket.entries.length) {
                         // Bucket is empty, so remove it from the bucket collections
diff --git a/libraries/stdlib/test/js/MapJsTest.kt b/libraries/stdlib/test/js/MapJsTest.kt
index 9e976453f7a..96d86e1e70d 100644
--- a/libraries/stdlib/test/js/MapJsTest.kt
+++ b/libraries/stdlib/test/js/MapJsTest.kt
@@ -23,6 +23,7 @@ class ComplexMapJsTest : MapJsTest() {
     override fun <T : kotlin.Comparable<T>> Collection<T>.toNormalizedList(): List<T> = this.toSortedList()
     // hashMapOf returns ComlpexHashMap because it is Generic
     override fun emptyMutableMap(): MutableMap<String, Int> = hashMapOf()
+    override fun emptyMutableMapWithNullableKeyValue(): MutableMap<String?, Int?> = hashMapOf()
 }
 
 class PrimitiveMapJsTest : MapJsTest() {
@@ -39,6 +40,7 @@ class PrimitiveMapJsTest : MapJsTest() {
 
     override fun <T : kotlin.Comparable<T>> Collection<T>.toNormalizedList(): List<T> = this.toSortedList()
     override fun emptyMutableMap(): MutableMap<String, Int> = HashMap()
+    override fun emptyMutableMapWithNullableKeyValue(): MutableMap<String?, Int?> = HashMap()
 }
 
 class LinkedHashMapTest : MapJsTest() {
@@ -55,6 +57,7 @@ class LinkedHashMapTest : MapJsTest() {
 
     override fun <T : kotlin.Comparable<T>> Collection<T>.toNormalizedList(): List<T> = this.toList()
     override fun emptyMutableMap(): MutableMap<String, Int> = LinkedHashMap()
+    override fun emptyMutableMapWithNullableKeyValue(): MutableMap<String?, Int?> = LinkedHashMap()
 }
 
 abstract class MapJsTest {
@@ -224,6 +227,31 @@ abstract class MapJsTest {
         assertTrue(map.isEmpty())
     }
 
+    test fun nullAsKey() {
+        val map = emptyMutableMapWithNullableKeyValue()
+
+        assertTrue(map.isEmpty())
+        map.put(null, 23)
+        assertFalse(map.isEmpty())
+        assertTrue(map.containsKey(null))
+        assertEquals(23, map[null])
+        assertEquals(23, map.remove(null))
+        assertTrue(map.isEmpty())
+        assertEquals(null, map[null])
+    }
+
+    test fun nullAsValue() {
+        val map = emptyMutableMapWithNullableKeyValue()
+        val KEY = "Key"
+
+        assertTrue(map.isEmpty())
+        map.put(KEY, null)
+        assertFalse(map.isEmpty())
+        assertEquals(null, map[KEY])
+        assertTrue(map.containsValue(null))
+        assertEquals(null, map.remove(KEY))
+        assertTrue(map.isEmpty())
+    }
     /*
 
     TODO fix bug with .set() on Map...
@@ -444,6 +472,8 @@ abstract class MapJsTest {
 
     abstract fun emptyMutableMap(): MutableMap<String, Int>
 
+    abstract fun emptyMutableMapWithNullableKeyValue(): MutableMap<String?, Int?>
+
     fun createTestMap(): Map<String, Int> = createTestMutableMap()
 
     fun createTestMutableMap(): MutableMap<String, Int> {
diff --git a/libraries/stdlib/test/js/SetJsTest.kt b/libraries/stdlib/test/js/SetJsTest.kt
index 6cf3a28a4a3..f09e026e8d2 100644
--- a/libraries/stdlib/test/js/SetJsTest.kt
+++ b/libraries/stdlib/test/js/SetJsTest.kt
@@ -22,10 +22,13 @@ class ComplexSetJsTest : SetJsTest() {
     }
 
     // hashSetOf returns ComlpexHashSet because it is Generic
-    override fun createEmptyMutableSet(): MutableSet<String> = hashSetOf<String>()
+    override fun createEmptyMutableSet(): MutableSet<String> = hashSetOf()
+    override fun createEmptyMutableSetWithNullableValues(): MutableSet<String?> = hashSetOf()
 }
 
 class PrimitiveSetJsTest : SetJsTest() {
+    override fun createEmptyMutableSet(): MutableSet<String> = HashSet()
+    override fun createEmptyMutableSetWithNullableValues(): MutableSet<String?> = HashSet()
     test override fun constructors() {
         HashSet<String>()
         HashSet<String>(3)
@@ -35,11 +38,11 @@ class PrimitiveSetJsTest : SetJsTest() {
 
         assertEquals(data, set)
     }
-
-    override fun createEmptyMutableSet(): MutableSet<String> = HashSet<String>()
 }
 
 class LinkedHashSetTest : SetJsTest() {
+    override fun createEmptyMutableSet(): MutableSet<String> = LinkedHashSet()
+    override fun createEmptyMutableSetWithNullableValues(): MutableSet<String?> = LinkedHashSet()
     test override fun constructors() {
         LinkedHashSet<String>()
         LinkedHashSet<String>(3)
@@ -49,8 +52,6 @@ class LinkedHashSetTest : SetJsTest() {
 
         assertEquals(data, set)
     }
-
-    override fun createEmptyMutableSet(): MutableSet<String> = LinkedHashSet<String>()
 }
 
 abstract class SetJsTest {
@@ -187,8 +188,20 @@ abstract class SetJsTest {
 
     test abstract fun constructors()
 
+    Test fun nullAsValue() {
+        val set = createEmptyMutableSetWithNullableValues()
+
+        assertTrue(set.isEmpty(), "Set should be empty")
+        set.add(null)
+        assertFalse(set.isEmpty(), "Set should not be empty")
+        assertTrue(set.contains(null), "Set should contains null")
+        assertTrue(set.remove(null), "Expected true when remove null")
+        assertTrue(set.isEmpty(), "Set should be empty")
+    }
+
     //Helpers
     abstract fun createEmptyMutableSet(): MutableSet<String>
+    abstract fun createEmptyMutableSetWithNullableValues(): MutableSet<String?>
 
     fun createTestMutableSet(): MutableSet<String> {
         val set = createEmptyMutableSet()