Emacs setup for JavaScript

.emacs

;; ## Packages to Install ##
;; js2-mode
;; js2-refactor
;; xref-js2
;; sudo npm install -g tern
;; company-tern

(require 'package)
(let* ((no-ssl (and (memq system-type '(windows-nt ms-dos))
                    (not (gnutls-available-p))))
       (proto (if no-ssl "http" "https")))
  (when no-ssl
    (warn "\                                                                                                                                                      
Your version of Emacs does not support SSL connections,                                                                                                           
which is unsafe because it allows man-in-the-middle attacks.                                                                                                      
There are two things you can do about this warning:                                                                                                               
1. Install an Emacs version that does support SSL and be safe.                                                                                                    
2. Remove this warning from your init file so you won't see it again."))
  ;; Comment/uncomment these two lines to enable/disable MELPA and MELPA Stable as desired                                                                        
  ;;(add-to-list 'package-archives (cons "melpa" (concat proto "://melpa.org/packages/")) t)                                                                      
  (add-to-list 'package-archives (cons "melpa-stable" (concat proto "://stable.melpa.org/packages/")) t)
  (when (< emacs-major-version 24)
    ;; For important compatibility libraries like cl-lib                                                                                                          
    (add-to-list 'package-archives (cons "gnu" (concat proto "://elpa.gnu.org/packages/")))))
(package-initialize)
(custom-set-variables
 (require 'js2-refactor)
(require 'xref-js2)

(add-hook 'js2-mode-hook #'js2-refactor-mode)
(js2r-add-keybindings-with-prefix "C-c C-r")
(define-key js2-mode-map (kbd "C-k") #'js2r-kill)

;; js-mode (which js2 is based on) binds "M-." which conflicts with xref, so                                                                                      
;; unbind it.                                                                                                                                                     
(define-key js-mode-map (kbd "M-.") nil)

(add-hook 'js2-mode-hook (lambda ()
  (add-hook 'xref-backend-functions #'xref-js2-xref-backend nil t)))

(require 'company)
(require 'company-tern)

(add-to-list 'company-backends 'company-tern)
(add-hook 'js2-mode-hook (lambda ()
                           (tern-mode)
                           (company-mode)))

;; Disable completion keybindings, as we use xref-js2 instead                                                                                                     
(define-key tern-mode-keymap (kbd "M-.") nil)
(define-key tern-mode-keymap (kbd "M-,") nil)
 ;; custom-set-variables was added by Custom.                                                                                                                     
 ;; If you edit it by hand, you could mess it up, so be careful.                                                                                                  
 ;; Your init file should contain only one such instance.                                                                                                         
 ;; If there is more than one, they won't work right.                                                                                                             
 '(package-selected-packages (quote (company-tern xref-js2 js2-refactor))))
(custom-set-faces
 ;; custom-set-faces was added by Custom.                                                                                                                         
 ;; If you edit it by hand, you could mess it up, so be careful.                                                                                                  
 ;; Your init file should contain only one such instance.                                                                                                         
 ;; If there is more than one, they won't work right.                                                                                                             
 )

(require 'js2-mode)
(add-to-list 'auto-mode-alist '("\\.js\\'" . js2-mode))

;; Better imenu                                                                                                                                                   
(add-hook 'js2-mode-hook #'js2-imenu-extras-mode)