(defun convert-coffee-2-js ()
  (interactive)
  (let ((do-it (y-or-n-p "Delete coffee file?"))
        (coffee-filename (buffer-file-name))
        (js-filename (concat (file-name-sans-extension coffee-filename) ".js")))
    (shell-command
     (format "decaffeinate %s" og-filename))
    (if do-it
        (progn
          (delete-file coffee-filename)
          (kill-buffer)))))