init.el

;; ensure tabs are specially colored, since they mess up things in
;; langs like coffeescript
(defface extra-whitespace-face
  '((t (:background "pale green")))
  "Used for tabs and such.")

(defvar my-extra-keywords
  '(("\t" . 'extra-whitespace-face)))

;; coffeescript specific hooks
(defun coffee-init ()
  (font-lock-add-keywords nil my-extra-keywords)
  (define-key coffee-mode-map

    ;; move point forward a line and to indent level of prev line
    (kbd "C-j") (lambda () (interactive)
                  (newline)
                  (let ((col (save-excursion (forward-line -1)
                                             (beginning-of-line)
                                             (skip-syntax-forward "-"))))
                    (indent-to col))))

  (hungry-delete-mode 1))

(add-hook 'coffee-mode-hook
          'coffee-init)