js2-mode.el

(use-package js2-mode
  :ensure t
  :after web-mode
  :config
  (require 'js2-mode)
  (add-to-list 'auto-mode-alist '("\\.js$" . js2-mode))
  (add-to-list 'auto-mode-alist '("\\.es6$" . js2-mode))
  (add-to-list 'auto-mode-alist '("\\.amd$" . js2-mode))

  (replace-auto-mode 'javascript-mode 'js2-mode)
  (replace-auto-mode 'js-mode 'js2-mode)

  ;; js2 configuration
  (setq js2-basic-offset 2)
  (setq js2-mode-indent-ignore-first-tab t)
  (setq js2-highlight-external-variables nil)
  (setq js2-highlight-level 3)
  (setq js2-mirror-mode nil)
  (setq js2-mode-show-parse-errors nil)
  (setq js2-mode-show-strict-warnings nil)
  (setq js2-bounce-indent-p nil)
  (setq js2-pretty-multiline-declarations t)

  (defun my-js2-mode-hook ()
    (local-set-key (kbd "<return>") 'newline-and-indent))

  (add-hook 'js2-mode-hook 'my-js2-mode-hook)
  (add-hook 'js2-mode-hook 'subword-mode)
  (add-to-list 'auto-mode-alist '("\\.jsx\\'" . web-mode)))