获取未定义不是一个功能

Question

使用coffeescript呼叫Stripe并在此行中获取undefined is not a function：$.StripeJS.stripeResponseHandler($form)

我也尝试过： @.stripeResponseHandler($form) -和- StripeJS.stripeResponseHandler($form)

代码：

class StripeJS
  constructor: (formId) ->
    @.setStripeResponseHandlerForForm(formId)

  stripeResponseHandler = (status, response, $form) ->
    console.log 'In stripeResponseHandler'

    if (response.error)
      #Clear the errors on the form
      $form.find('.payment-errors').html ''
      #Show the errors on the form
      $form.find('.payment-errors').append ('<div class="alert alert-error">
          <a class="close" data-dismiss="alert">×</a>
          <li>' + response.error.message + '</li>
        </div>')
      $form.find('button').prop 'disabled', false
    else
      # response contains id and card, which contains additional card details
      # Insert the token into the form so it gets submitted to the server
      $('#stripe_card_token').val response.id
      # and submit
      $form.get(0).submit()

  setStripeResponseHandlerForForm: (formId) ->
    Stripe.setPublishableKey $('meta[name="stripe-key"]').attr('content')
    $("#{formId}").submit (event) ->
      console.log 'In setStripeResponseHandlerForForm'
      $form = $(this)
      # Disable the submit button to prevent repeated clicks
      $form.find('button').prop 'disabled', true

      console.log 'About to call out to Stripe'
      Stripe.createToken $form, (status,response) ->
        $.StripeJS.stripeResponseHandler($form)
      console.log 'Back from calling stripe'
    # Prevent the form from submitting with the default action
      return false

$(document).ready ->
  $.StripeJS = new StripeJS('#new_agent')