function to copy objects

test/index.js

@@ -30,3 +30,11 @@ test ('try_parse_json should fail', (t) => {
     t.is (json, null);
   });
 });
+
+test ('copy object', (t) => {
+  const obj = {foo:'bar'};
+  const copy = util.copy_object(obj);
+  copy.foo = 'baz';
+  t.is(copy.foo, 'baz');
+  t.is(obj.foo, 'bar');
+});