Parse在更新时删除数组内的对象

Question

我的应用程序上有类似的功能，当用户双击时，它会在Parse上为数组添加用户名。但是，只要另一个用户双击，它就会附加数组，但会删除已存在的其他用户。这是我的代码！

var userLikes = [PFUser.current()]

func doubleTapped(){
    postedImage.alpha = 0
    UIView.animate(withDuration: 1, animations: {

        self.postedImage.alpha = 1

    })
  let likesQuery = PFQuery(className: "FeatherPosts")
    likesQuery.getObjectInBackground(withId: objectIdLabel.text!) { (object, error) in
        if error != nil {
            print ("error")
        }else{
            if let userLikes = object {
                userLikes["UserLikes"] = [self.userLikes]
                self.userLikes.append(PFUser.current().self)
                userLikes.saveInBackground(block: { (success, error) in
                    if success {
                        print("liked")
                    }else{
                        print("error")
                    }
                })
            }

        }
    }
 }

请帮忙。我还在学习Parse，所以请善待。哈哈