在CoffeeScript中调用全局函数

我在喝咖啡时有一种奇怪的行为 initMap 从加载的脚本中正确调用函数( &callback=initMap ),但我有一个错误是由上一行触发的 initMap()

# Declare a global function
@initMap = ->
  restaurantLocation =
    lat: $('#restaurant-map').data("lat")
    lng: $('#restaurant-map').data("lng")
  map = new (google.maps.Map) $('#restaurant-map')[0],
    zoom: 19,
    center: restaurantLocation
  marker = new (google.maps.Marker)
    position: restaurantLocation
    map: map

$(document).on 'turbolinks:load', ->
  if $('#restaurant-map').length > 0
    if page.included_google_maps_js_api == undefined
      google_maps_api_key = 'xxx'
      # correctly called from here...
      $.getScript('https://maps.googleapis.com/maps/api/js?key=' + google_maps_api_key + '&callback=initMap')
      page.included_google_maps_js_api = true
    initMap() # Uncaught ReferenceError: google is not defined

我觉得有趣的是,另一个片段完美无瑕:

$(document).on 'turbolinks:load', ->
  if $('#restaurant-map').length > 0 && page.included_google_maps_js_api == undefined
    google_maps_api_key = 'xxx'
    $.getScript('https://maps.googleapis.com/maps/api/js?key=' + google_maps_api_key + '&callback=initMap')
    page.included_google_maps_js_api = true
  else if ($('#restaurant-map').length > 0)
    initMap()