অ্যাঙ্গুলারজেএস copy

<!DOCTYPE html>
<html>
<body>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.8.3/angular.min.js"></script>
  <script>
    var user = {
      name: "আরিফ",
      land: "বাংলাদেশ"
    };

    var copy = angular.copy(user);
    copy.name = "সাকিব";

    document.write(user.name);
    document.write(copy.name);
  </script>

</body>
</html>