Emacs JSON sort

json-sort.el

(require 'json)

(defun sort-json (point)
  "Sort JSON-like structure surrounding the point."
  (interactive "d")
  (let ((object-begin (nth 1 (syntax-ppss point)))
        (begin-point (point)))
    (when object-begin
      (goto-char object-begin)
      (forward-list)

      (with-current-buffer (current-buffer)
        (json-pretty-print-ordered object-begin (point))
        (indent-region object-begin (point)))

      (goto-char begin-point))))

Does it work with a region?, I want to sort a js object, not a json