init.el

(add-hook 'js2-mode-hook 'qoobaa/js2-mode-setup)

(defun qoobaa/js2-mode-setup ()
  (let ((local-eslint (expand-file-name "node_modules/.bin/eslint" (projectile-project-root))))
    (when (file-exists-p local-eslint)
      (setq flycheck-javascript-eslint-executable local-eslint)
      (js2-mode-hide-warnings-and-errors)
      (flycheck-mode t)
      (flycheck-select-checker 'javascript-eslint))))