Javascript 为什么在我的茶匙/茉莉花规格测试中数字不是构造器？

我正在尝试测试一个.js.coffee文件，但不断出现错误：

Failure/Error:TypeError:undefined不是构造函数（正在计算'Number.isNaN（likecount）'）

我相信我需要在我的规范文件中包含这个数字，我该怎么做？我是新的规格测试

这是我的js.coffee文件

class Page.LikeButtons
  constructor: (@el) ->
    Page.handleAjaxOn @el.find('.js-create-like'), (event, data) =>
      @_increaseCountOnPage()

  _increaseCountOnPage: () ->
    likesContent = @el.find('button.like-count.js-show-modal')
    likesElement = likesContent[0].innerHTML.split(' ')
    likesCount = parseInt(likesElement[0])
    like = "Likes"
    if (Number.isNaN(likesCount))
      like = "Like";
      likesCount = 0;
    likesContent[0].innerHTML = "#{parseInt(likesCount) + 1 } #{like}"

$(document).ready ->
  for el in $('.js-like-button-container')
    new Page.LikeButtons($(el))

describe 'like buttons', ->
  beforeEach ->
    setFixtures ''' 
      <div class="js-like-button-container" data-taste-id="456">
        <div class="hidden js-hideable-modal"></div>
          <button class="like-count js-show-modal"></button>
        <div class="js-create-like"></div>
        <div class="js-delete-like"></div>
      </div>
    '''

    new Page.LikeButtons($('.js-like-button-container'))

  describe 'when the user clicks to like', ->
    beforeEach ->
      $('.js-create-like').trigger('ajax:success', [{like: {id: 123}}])

    it 'classes the container as current-likes', ->
      expect($('.js-like-button-container')).toHaveClass 'current-likes'

    it 'builds an href for the delete button for the created like', ->
      expect($('.js-delete-like').attr('href')).toEqual(
        '/api/...'
      )

这是我的spec.js.coffee文件

class Page.LikeButtons
  constructor: (@el) ->
    Page.handleAjaxOn @el.find('.js-create-like'), (event, data) =>
      @_increaseCountOnPage()

  _increaseCountOnPage: () ->
    likesContent = @el.find('button.like-count.js-show-modal')
    likesElement = likesContent[0].innerHTML.split(' ')
    likesCount = parseInt(likesElement[0])
    like = "Likes"
    if (Number.isNaN(likesCount))
      like = "Like";
      likesCount = 0;
    likesContent[0].innerHTML = "#{parseInt(likesCount) + 1 } #{like}"

$(document).ready ->
  for el in $('.js-like-button-container')
    new Page.LikeButtons($(el))

describe 'like buttons', ->
  beforeEach ->
    setFixtures ''' 
      <div class="js-like-button-container" data-taste-id="456">
        <div class="hidden js-hideable-modal"></div>
          <button class="like-count js-show-modal"></button>
        <div class="js-create-like"></div>
        <div class="js-delete-like"></div>
      </div>
    '''

    new Page.LikeButtons($('.js-like-button-container'))

  describe 'when the user clicks to like', ->
    beforeEach ->
      $('.js-create-like').trigger('ajax:success', [{like: {id: 123}}])

    it 'classes the container as current-likes', ->
      expect($('.js-like-button-container')).toHaveClass 'current-likes'

    it 'builds an href for the delete button for the created like', ->
      expect($('.js-delete-like').attr('href')).toEqual(
        '/api/...'
      )

描述“类似按钮”，->
每次之前->
设置装置“”'
'''
新页面.LikeButtons（$（'.js like按钮容器'））
描述“当用户单击以喜欢”时，->
每次之前->
$（'.js create like'）.trigger（'ajax:success'，[{like:{id:123}}]））
它“将容器分类为当前喜欢的容器”，->
expect（$（'.js like button container'））.toHaveClass“current like”
它“为已创建的类的删除按钮构建href”，->
expect（$（'.js delete like'）.attr（'href'））.toEqual(
“/api/…”
)

因为

isNaN

不是

Number

的方法，而是

Number

的构造函数。因此，当您编写

Number.isNaN（likescont）

时，它被解释为一个构造函数。尝试

isNaN（likescont）

代替。使用isNaN（likescont）确实解决了这个问题，谢谢！！