diff --git a/jso/apis/src/main/java/org/teavm/jso/core/JSArray.java b/jso/apis/src/main/java/org/teavm/jso/core/JSArray.java
index b62178a51..206a36e90 100644
--- a/jso/apis/src/main/java/org/teavm/jso/core/JSArray.java
+++ b/jso/apis/src/main/java/org/teavm/jso/core/JSArray.java
@@ -91,6 +91,10 @@ public abstract class JSArray<T extends JSObject> implements JSArrayReader<T> {
     @NoSideEffects
     public static native <T extends JSObject> JSArray<T> create(int size);
 
+    @JSBody(params = "object", script = "return Array.isArray(object);")
+    @NoSideEffects
+    public static native boolean isArray(JSObject object);
+
     @SafeVarargs
     public static <S extends JSObject> JSArray<S> of(S... items) {
         JSArray<S> array = create(items.length);
diff --git a/jso/apis/src/main/java/org/teavm/jso/core/JSObjects.java b/jso/apis/src/main/java/org/teavm/jso/core/JSObjects.java
index 0939c08b7..020fab64b 100644
--- a/jso/apis/src/main/java/org/teavm/jso/core/JSObjects.java
+++ b/jso/apis/src/main/java/org/teavm/jso/core/JSObjects.java
@@ -27,6 +27,14 @@ public final class JSObjects {
     @NoSideEffects
     public static native String[] getOwnPropertyNames(JSObject object);
 
+    @JSBody(params = "object", script = "return Object.keys(object);")
+    @NoSideEffects
+    public static native String[] keys(JSObject object);
+
+    @JSBody(params = "object", script = "return Object.values(object);")
+    @NoSideEffects
+    public static native JSObject[] values(JSObject object);
+
     @JSBody(script = "return {};")
     @NoSideEffects
     public static native <T extends JSObject> T create();