JS: fix unwrapping JS objects implemented in Java

jso/impl/src/main/java/org/teavm/jso/impl/JSWrapper.java

@@ -165,14 +165,14 @@ public final class JSWrapper {
         if (o == null) {
             return null;
         }
-        return ((JSWrapper) o).js;
+        return o instanceof JSWrapper ? ((JSWrapper) o).js : directJavaToJs(o);
     }
 
     public static JSObject maybeUnwrap(Object o) {
         if (o == null) {
             return null;
         }
-        return isJava(o) ? unwrap(o) : directJavaToJs(o);
+        return o instanceof JSWrapper ? unwrap(o) : directJavaToJs(o);
     }
 
     public static JSObject javaToJs(Object o) {

tests/src/test/java/org/teavm/jso/test/JSWrapperTest.java

@@ -292,6 +292,25 @@ public class JSWrapperTest {
         assertEquals(JSNumber.valueOf(23), getProperty(o, "foo"));
     }
 
+    @Test
+    public void createArray() {
+        var array = new J[] {
+                new JImpl(23),
+                new JImpl(42)
+        };
+        assertEquals(23, array[0].foo());
+        assertEquals(42, callFoo(array[1]));
+        assertEquals("23,42", concatFoo(array));
+    }
+
+    @Test
+    public void createArrayAndReturnToJS() {
+        assertEquals("23,42", concatFoo(() -> new J[] {
+                new JImpl(23),
+                new JImpl(42)
+        }));
+    }
+
     private void callSetProperty(Object instance, Object o) {
         setProperty(instance, "foo", o);
     }
@@ -341,4 +360,35 @@ public class JSWrapperTest {
     interface ReturningObject extends JSObject {
         Object get();
     }
+
+    @JSBody(params = "o", script = "return o.foo();")
+    private static native int callFoo(JSObject o);
+
+    @JSBody(params = "array", script = "return array[0].foo() + ',' + array[1].foo(); ")
+    private static native String concatFoo(J[] array);
+
+    @JSBody(params = "supplier", script = "let array = supplier.get(); "
+            + "return array[0].foo() + ',' + array[1].foo();")
+    private static native String concatFoo(JArraySupplier supplier);
+
+    interface J extends JSObject {
+        int foo();
+    }
+
+    class JImpl implements J {
+        private int value;
+
+        JImpl(int value) {
+            this.value = value;
+        }
+
+        @Override
+        public int foo() {
+            return value;
+        }
+    }
+
+    interface JArraySupplier extends JSObject {
+        J[] get();
+    }
 }