add object merging

Author: mudkipdev

json/src/main/java/alpine/json/Element.java

@@ -85,4 +85,20 @@ static ObjectElement object() {
     static ObjectElement object(Map<String, Element> map) {
         return new ObjectElement(new LinkedHashMap<>(map));
     }
+
+    static ObjectElement object(Collection<ObjectElement> objects) {
+        var map = new LinkedHashMap<String, Element>();
+        objects.forEach(object -> object.each(map::put));
+        return new ObjectElement(map);
+    }
+
+    static ObjectElement object(ObjectElement... objects) {
+        var map = new LinkedHashMap<String, Element>();
+
+        for (var object : objects) {
+            object.each(map::put);
+        }
+
+        return new ObjectElement(map);
+    }
 }

json/src/test/java/alpine/json/JsonTest.java

@@ -91,6 +91,13 @@ void testObjectSorting() {
         assertEquals(unsortedObject.sort().toString(), sortedObject.toString());
     }
 
+    @Test
+    void testObjectMerging() {
+        var firstObject = object().set("a", "b");
+        var secondObject = object().set("c", "d");
+        assertEquals(object(firstObject, secondObject), object().set("a", "b").set("c", "d"));
+    }
+
     @ParameterizedTest(name = "{0} (encoding)")
     @MethodSource("arguments")
     void testEncoding(String label, Element element, String expected) {