Question

出于某种原因，我无法在Backbone应用程序中多次实例化视图。我给了undefined is not a function。为什么会这样？

app.coffee

define [
  'views/start'
], (
  StartView
) ->

  initialize = ->   

    # Take us to the start view
    startView = new StartView()
    startView.render() # Works just fine

  initialize: initialize

视图/ start.coffee

define [
  'jquery'
  'underscore'
  'backbone'
  'text!templates/start.html'
  'views/question'
], (
  $
  _
  Backbone
  StartTemplate
  QuestionView
) ->

  StartView = Backbone.View.extend

    events:
      'click #btn-begin': 'pushQuestionView'

    render: ->

      # Create a template and stuff it into the view element
      @$el.html @template = _.template StartTemplate

      # Inject the HTML in the document
      $('#main').html @el

      # Return view for chaining
      @

    pushQuestionView: ->

      questionView = new QuestionView()
      questionView.render()

  StartView

视图/ question.coffee

define [
  'jquery'
  'underscore'
  'backbone'
  'text!templates/question.html'
  'views/form'
  'views/start'
], (
  $
  _
  Backbone
  QuestionTemplate
  FormView
  StartView
) ->

  QuestionView = Backbone.View.extend

    events:
      'click #btn-prev': 'goBack'

    render: ->

      # Create a template and stuff it into the view element
      @$el.html @template = _.template QuestionTemplate

      # Inject the HTML in the document
      $('#main').html @$el

      # Return for chaining
      @

    goBack: ->

      console.log StartView # => undefined

      startView = new StartView() # => Uncaught TypeError: undefined is not a function
      startView.render()

  QuestionView

因为它第一次工作，所以它不能是语法错误。

Answer 1

您指的是question中的start和start中的question。它形成循环依赖。这就是造成这个问题的原因。

来自require.js - circular dependency文档。

如果你定义一个循环依赖（需要b和b需要a），那么在这种情况下，当调用b的模块函数时，它将得到一个未定义的 a。的价值。

无法再次实例化Backbone视图

1 个答案: