make facebook sdk work with turbolinks on rails 4

facebook_sdk.js.coffee

appId = *******

$ ->
  loadFacebookSDK()
  bindFacebookEvents() unless window.fbEventsBound

bindFacebookEvents = ->
  $(document)
    .on('page:fetch', saveFacebookRoot)
    .on('page:change', restoreFacebookRoot)
    .on('page:load', ->
      FB?.XFBML.parse()
    )
  @fbEventsBound = true

saveFacebookRoot = ->
  if $('#fb-root').length
    @fbRoot = $('#fb-root').detach()

restoreFacebookRoot = ->
  if @fbRoot?
    if $('#fb-root').length
      $('#fb-root').replaceWith @fbRoot
    else
      $('body').append @fbRoot

loadFacebookSDK = ->
  window.fbAsyncInit = initializeFacebookSDK
  $.getScript("//connect.facebook.net/en_US/sdk.js#xfbml=1&version=v2.4&appId=#{appId}")

initializeFacebookSDK = ->
  FB.init
    appId  : appId
    status : true
    cookie : true
    xfbml  : true
    version: "v2.4"