diff --git a/js/js.translator/testData/maps.js b/js/js.translator/testData/maps.js
index bc222f7f629..565bc253777 100644
--- a/js/js.translator/testData/maps.js
+++ b/js/js.translator/testData/maps.js
@@ -508,7 +508,7 @@
     Kotlin.PrimitiveHashMap = Kotlin.createClassNow(Kotlin.Map,
         function () {
             this.$size = 0;
-            this.map = {};
+            this.map = Object.create(null);
         }, {
             size: function () {
                 return this.$size;
@@ -517,12 +517,14 @@
                 return this.$size === 0;
             },
             containsKey_za3rmp$: function (key) {
+                // TODO: should process "__proto__" separately?
                 return this.map[key] !== undefined;
             },
             containsValue_za3rmp$: function (value) {
                 var map = this.map;
                 for (var key in map) {
-                    if (map.hasOwnProperty(key) && map[key] === value) {
+                    //noinspection JSUnfilteredForInLoop
+                    if (map[key] === value) {
                         return true;
                     }
                 }
@@ -555,19 +557,17 @@
             putAll_za3j1t$: function (fromMap) {
                 var map = fromMap.map;
                 for (var key in map) {
-                    if (map.hasOwnProperty(key)) {
-                        this.map[key] = map[key];
-                        this.$size++;
-                    }
+                    //noinspection JSUnfilteredForInLoop
+                    this.map[key] = map[key];
+                    this.$size++;
                 }
             },
             entrySet: function () {
                 var result = new Kotlin.ComplexHashSet();
                 var map = this.map;
                 for (var key in map) {
-                    if (map.hasOwnProperty(key)) {
-                        result.add_za3rmp$(new Entry(key, map[key]));
-                    }
+                    //noinspection JSUnfilteredForInLoop
+                    result.add_za3rmp$(new Entry(key, map[key]));
                 }
 
                 return result;
@@ -576,9 +576,8 @@
                 var result = new Kotlin.PrimitiveHashSet();
                 var map = this.map;
                 for (var key in map) {
-                    if (map.hasOwnProperty(key)) {
-                        result.add_za3rmp$(key);
-                    }
+                    //noinspection JSUnfilteredForInLoop
+                    result.add_za3rmp$(key);
                 }
 
                 return result;
diff --git a/libraries/stdlib/test/js/MapJsTest.kt b/libraries/stdlib/test/js/MapJsTest.kt
index 4e288d97673..0ee938152ba 100644
--- a/libraries/stdlib/test/js/MapJsTest.kt
+++ b/libraries/stdlib/test/js/MapJsTest.kt
@@ -26,6 +26,8 @@ abstract class MapJsTest {
     val KEYS = array("zero", "one", "two", "three").toList()
     val VALUES = array(0, 1, 2, 3).toList()
 
+    val SPECIAL_NAMES = array("__proto__", "constructor", "toString", "toLocaleString", "valueOf", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable")
+
     test fun getOrElse() {
         val data = emptyMap()
         val a = data.getOrElse("foo"){2}
@@ -246,6 +248,42 @@ abstract class MapJsTest {
         assertEquals(VALUES.toNormalizedList(), actualValues.toNormalizedList())
     }
 
+    test fun specialNamesNotContainsInEmptyMap() {
+        val map = emptyMap()
+
+        for (key in SPECIAL_NAMES) {
+            assertFalse(map.containsKey(key), "unexpected key: $key")
+        }
+    }
+
+    test fun specialNamesNotContainsInNonEmptyMap() {
+        val map = createTestMap()
+
+        for (key in SPECIAL_NAMES) {
+            assertFalse(map.containsKey(key), "unexpected key: $key")
+        }
+    }
+
+    test fun putAndGetSpecialNamesToMap() {
+        val map = createTestMutableMap()
+        var value = 0
+
+        for (key in SPECIAL_NAMES) {
+            assertFalse(map.containsKey(key), "unexpected key: $key")
+
+            map.put(key, value)
+            assertTrue(map.containsKey(key), "key not found: $key")
+
+            val actualValue = map.get(key)
+            assertEquals(value, actualValue, "wrong value fo key: $key")
+
+            map.remove(key)
+            assertFalse(map.containsKey(key), "unexpected key after remove: $key")
+
+            value += 3
+        }
+    }
+
     /*
     test fun createLinkedMap() {
         val map = linkedMapOf("c" to 3, "b" to 2, "a" to 1)
diff --git a/libraries/stdlib/test/js/SetJsTest.kt b/libraries/stdlib/test/js/SetJsTest.kt
index eb9e846d253..0d2f8719823 100644
--- a/libraries/stdlib/test/js/SetJsTest.kt
+++ b/libraries/stdlib/test/js/SetJsTest.kt
@@ -22,6 +22,8 @@ abstract class SetJsTest {
     val data: Set<String> = createTestMutableSet()
     val empty: Set<String> = createEmptyMutableSet()
 
+    val SPECIAL_NAMES = array("__proto__", "constructor", "toString", "toLocaleString", "valueOf", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable")
+
     Test fun size() {
         assertEquals(2, data.size())
         assertEquals(0, empty.size())
@@ -122,6 +124,32 @@ abstract class SetJsTest {
         assertTrue(data.isEmpty())
     }
 
+    Test fun specialNamesNotContainsInEmptySet() {
+        for (element in SPECIAL_NAMES) {
+            assertFalse(empty.contains(element), "unexpected element: $element")
+        }
+    }
+
+    Test fun specialNamesNotContainsInNonEmptySet() {
+        for (element in SPECIAL_NAMES) {
+            assertFalse(data.contains(element), "unexpected element: $element")
+        }
+    }
+
+    Test fun putAndGetSpecialNamesToSet() {
+        val s = createTestMutableSet()
+
+        for (element in SPECIAL_NAMES) {
+            assertFalse(s.contains(element), "unexpected element: $element")
+
+            s.add(element)
+            assertTrue(s.contains(element), "element not found: $element")
+
+            s.remove(element)
+            assertFalse(s.contains(element), "unexpected element after remove: $element")
+        }
+    }
+
     //Helpers
     abstract fun createEmptyMutableSet(): MutableSet<String>