Create a new scratch buffer in emacs

create-scratch-buffer.el

(defun create-scratch-buffer (&optional nomode)
  "Create a new scratch buffer and switch to it. If the region is active, then
 paste the contents of the region in the new buffer. The new buffer inherits
 the mode of the original buffer unless nomode is set.
 Return the buffer."
  (interactive "P")
  (let ((bufname (get-buffer-create (generate-new-buffer-name "*scratch*")))
        (mjmode (if nomode 'fundamental-mode (major-mode-remap major-mode))))
    (when (use-region-p)
      (insert-into-buffer bufname (point) (mark t))
      (deactivate-mark))
    (switch-to-buffer bufname)
    (goto-char (point-min))
    (funcall mjmode)
    (get-buffer bufname)))