rename js variable in lexical scope

js2r.ext.el

(defun js2r-rename-var (replacement)
  "Renames the variable on point and all occurrences in its lexical scope."
  (interactive "sInput the replacement: ")
;  (js2r--guard)
  (let* ((current-node (js2r--local-name-node-at-point))
         (len (js2-node-len current-node))
         (offset (- (length replacement) len))
         (current-start (js2-node-abs-pos current-node))
         (current-end (+ current-start len)))

    (goto-char current-start)
    (delete-region (point) (+ (point) len))
    (insert replacement)

    (save-excursion
      (mapc (lambda (beg)
              (when (not (= beg current-start))
                (if (> beg current-start)
                    (goto-char (+ offset beg))
                    (goto-char beg))
                (delete-region (point) (+ (point) len))
                (insert replacement)
                ))
            (js2r--local-var-positions current-node)))))