Flycheck with JSCS

.emacs

;; Flycheck JSCS
(flycheck-def-config-file-var flycheck-jscs javascript-jscs ".jscs.json"
  :safe #'stringp)
(flycheck-define-checker javascript-jscs
  "A JavaScript code style checker.
See URL `https://github.com/mdevils/node-jscs'."
  :command ("jscs" "--reporter" "checkstyle"
            (config-file "--config" flycheck-jscs)
            source)
  :error-parser flycheck-parse-checkstyle
  :modes (js-mode js2-mode js3-mode)
  :next-checkers (javascript-jshint))

(defun jscs-enable () (interactive)
       (add-to-list 'flycheck-checkers 'javascript-jscs))

(defun jscs-disable () (interactive)
       (setq flycheck-checkers (remove 'javascript-jscs flycheck-checkers)))