elisp mode test

(require 'dash)

(cl-defun mode-p (mode &optional (buffer (current-buffer)))
  "Return t if BUFFER is in major MODE, else nil."
  (when (bufferp buffer)
    (with-current-buffer buffer
      (eq mode major-mode))))

(defalias 'dired-mode-p (-partial #'mode-p 'dired-mode))

(defalias 'erc-mode-p (-partial #'mode-p 'erc-mode))