Add backbone checks.

lms/static/coffee/src/discussion/discussion_router.coffee

-class @DiscussionRouter extends Backbone.Router
-  routes:
-    "": "allThreads"
-    ":forum_name/threads/:thread_id" : "showThread"
-
-  initialize: (options) ->
-      @discussion = options['discussion']
-      @nav = new DiscussionThreadListView(collection: @discussion, el: $(".sidebar"))
-      @nav.on "thread:selected", @navigateToThread
-      @nav.on "thread:removed", @navigateToAllThreads
-      @nav.on "threads:rendered", @setActiveThread
-      @nav.render()
-
-      @newPostView = new NewPostView(el: $(".new-post-article"), collection: @discussion)
-      @newPostView.on "thread:created", @navigateToThread
-
-  allThreads: ->
-    @nav.updateSidebar()
-
-  setActiveThread: =>
-    if @thread
-      @nav.setActiveThread(@thread.get("id"))
-
-  showThread: (forum_name, thread_id) ->
-    @thread = @discussion.get(thread_id)
-    @setActiveThread()
-    if(@main)
-      @main.undelegateEvents()
-
-    @main = new DiscussionThreadView(el: $(".discussion-column"), model: @thread)
-    @main.render()
-    @main.on "thread:responses:rendered", =>
+if Backbone?
+  class @DiscussionRouter extends Backbone.Router
+    routes:
+      "": "allThreads"
+      ":forum_name/threads/:thread_id" : "showThread"
+
+    initialize: (options) ->
+        @discussion = options['discussion']
+        @nav = new DiscussionThreadListView(collection: @discussion, el: $(".sidebar"))
+        @nav.on "thread:selected", @navigateToThread
+        @nav.on "thread:removed", @navigateToAllThreads
+        @nav.on "threads:rendered", @setActiveThread
+        @nav.render()
+
+        @newPostView = new NewPostView(el: $(".new-post-article"), collection: @discussion)
+        @newPostView.on "thread:created", @navigateToThread
+
+    allThreads: ->
       @nav.updateSidebar()
 
-  navigateToThread: (thread_id) =>
-    thread = @discussion.get(thread_id)
-    @navigate("#{thread.get("commentable_id")}/threads/#{thread_id}", trigger: true)
+    setActiveThread: =>
+      if @thread
+        @nav.setActiveThread(@thread.get("id"))
 
-  navigateToAllThreads: =>
-    console.log "navigating"
-    @navigate("", trigger: true)
+    showThread: (forum_name, thread_id) ->
+      @thread = @discussion.get(thread_id)
+      @setActiveThread()
+      if(@main)
+        @main.undelegateEvents()
+
+      @main = new DiscussionThreadView(el: $(".discussion-column"), model: @thread)
+      @main.render()
+      @main.on "thread:responses:rendered", =>
+        @nav.updateSidebar()
+
+    navigateToThread: (thread_id) =>
+      thread = @discussion.get(thread_id)
+      @navigate("#{thread.get("commentable_id")}/threads/#{thread_id}", trigger: true)
+
+    navigateToAllThreads: =>
+      console.log "navigating"
+      @navigate("", trigger: true)

lms/static/coffee/src/discussion/main.coffee

-DiscussionApp =
-  start: (elem)->
-    # TODO: Perhaps eliminate usage of global variables when possible
-    element = $(elem)
-    window.$$course_id = element.data("course-id")
-    user_info = element.data("user-info")
-    threads = element.data("threads")
-    content_info = element.data("content-info")
-    window.user = new DiscussionUser(user_info)
-    Content.loadContentInfos(content_info)
-    discussion = new Discussion(threads)
-    new DiscussionRouter({discussion: discussion})
-    Backbone.history.start({pushState: true, root: "/courses/#{$$course_id}/discussion/forum/"})
+if Backbone?
+  DiscussionApp =
+    start: (elem)->
+      # TODO: Perhaps eliminate usage of global variables when possible
+      element = $(elem)
+      window.$$course_id = element.data("course-id")
+      user_info = element.data("user-info")
+      threads = element.data("threads")
+      content_info = element.data("content-info")
+      window.user = new DiscussionUser(user_info)
+      Content.loadContentInfos(content_info)
+      discussion = new Discussion(threads)
+      new DiscussionRouter({discussion: discussion})
+      Backbone.history.start({pushState: true, root: "/courses/#{$$course_id}/discussion/forum/"})
 
-$ ->
-  $("section.discussion").each (index, elem) ->
-    DiscussionApp.start(elem)
+  $ ->
+    $("section.discussion").each (index, elem) ->
+      DiscussionApp.start(elem)

lms/static/coffee/src/discussion/models/discussion_user.coffee

-class @DiscussionUser extends Backbone.Model
-    following: (thread) ->
-        _.include(@get('subscribed_thread_ids'), thread.id)
+if Backbone?
+  class @DiscussionUser extends Backbone.Model
+      following: (thread) ->
+          _.include(@get('subscribed_thread_ids'), thread.id)
 
-    voted: (thread) ->
-        _.include(@get('upvoted_ids'), thread.id)
+      voted: (thread) ->
+          _.include(@get('upvoted_ids'), thread.id)
 
-    vote: (thread) ->
-        @get('upvoted_ids').push(thread.id)
-        thread.vote()
+      vote: (thread) ->
+          @get('upvoted_ids').push(thread.id)
+          thread.vote()
 
-    unvote: (thread) ->
-        @set('upvoted_ids', _.without(@get('upvoted_ids'), thread.id))
-        thread.unvote()
+      unvote: (thread) ->
+          @set('upvoted_ids', _.without(@get('upvoted_ids'), thread.id))
+          thread.unvote()

lms/static/coffee/src/discussion/user_profile.coffee

-class @DiscussionUserProfileView extends Backbone.View
-  toggleModeratorStatus: (event) ->
-    confirmValue = confirm("Are you sure?")
-    if not confirmValue then return
-    $elem = $(event.target)
-    if $elem.hasClass("sidebar-promote-moderator-button")
-      isModerator = true
-    else if $elem.hasClass("sidebar-revoke-moderator-button")
-      isModerator = false
-    else
-      console.error "unrecognized moderator status"
-      return
-    url = DiscussionUtil.urlFor('update_moderator_status', $$profiled_user_id)
-    DiscussionUtil.safeAjax
-      $elem: $elem
-      url: url
-      type: "POST"
-      dataType: 'json'
-      data:
-        is_moderator: isModerator
-      error: (response, textStatus, e) ->
-        console.log e
-      success: (response, textStatus) =>
-        parent = @$el.parent()
-        @$el.replaceWith(response.html)
-        view = new DiscussionUserProfileView el: parent.children(".user-profile")
+if Backbone?
+  class @DiscussionUserProfileView extends Backbone.View
+    toggleModeratorStatus: (event) ->
+      confirmValue = confirm("Are you sure?")
+      if not confirmValue then return
+      $elem = $(event.target)
+      if $elem.hasClass("sidebar-promote-moderator-button")
+        isModerator = true
+      else if $elem.hasClass("sidebar-revoke-moderator-button")
+        isModerator = false
+      else
+        console.error "unrecognized moderator status"
+        return
+      url = DiscussionUtil.urlFor('update_moderator_status', $$profiled_user_id)
+      DiscussionUtil.safeAjax
+        $elem: $elem
+        url: url
+        type: "POST"
+        dataType: 'json'
+        data:
+          is_moderator: isModerator
+        error: (response, textStatus, e) ->
+          console.log e
+        success: (response, textStatus) =>
+          parent = @$el.parent()
+          @$el.replaceWith(response.html)
+          view = new DiscussionUserProfileView el: parent.children(".user-profile")
 
-  events:
-    "click .sidebar-toggle-moderator-button": "toggleModeratorStatus"
+    events:
+      "click .sidebar-toggle-moderator-button": "toggleModeratorStatus"

lms/static/coffee/src/discussion/views/discussion_content_view.coffee

-class @DiscussionContentView extends Backbone.View
-
-  attrRenderer:
-    endorsed: (endorsed) ->
-      if endorsed
-        @$(".action-endorse").addClass("is-endorsed")
-      else
-        @$(".action-endorse").removeClass("is-endorsed")
-
-    closed: (closed) ->
-      return if not @$(".action-openclose").length
-      return if not @$(".post-status-closed").length
-      if closed
-        @$(".post-status-closed").show()
-        @$(".action-openclose").html(@$(".action-openclose").html().replace("Close", "Open"))
-        @$(".discussion-reply-new").hide()
-      else
-        @$(".post-status-closed").hide()
-        @$(".action-openclose").html(@$(".action-openclose").html().replace("Open", "Close"))
-        @$(".discussion-reply-new").show()
-
-    voted: (voted) ->
-
-    votes_point: (votes_point) ->
-
-    comments_count: (comments_count) ->
-
-    subscribed: (subscribed) ->
-      if subscribed
-        @$(".dogear").addClass("is-followed")
-      else
-        @$(".dogear").removeClass("is-followed")
-
-    ability: (ability) ->
-      for action, selector of @abilityRenderer
-        if not ability[action]
-          selector.disable.apply(@)
+if Backbone?
+  class @DiscussionContentView extends Backbone.View
+
+    attrRenderer:
+      endorsed: (endorsed) ->
+        if endorsed
+          @$(".action-endorse").addClass("is-endorsed")
+        else
+          @$(".action-endorse").removeClass("is-endorsed")
+
+      closed: (closed) ->
+        return if not @$(".action-openclose").length
+        return if not @$(".post-status-closed").length
+        if closed
+          @$(".post-status-closed").show()
+          @$(".action-openclose").html(@$(".action-openclose").html().replace("Close", "Open"))
+          @$(".discussion-reply-new").hide()
+        else
+          @$(".post-status-closed").hide()
+          @$(".action-openclose").html(@$(".action-openclose").html().replace("Open", "Close"))
+          @$(".discussion-reply-new").show()
+
+      voted: (voted) ->
+
+      votes_point: (votes_point) ->
+
+      comments_count: (comments_count) ->
+
+      subscribed: (subscribed) ->
+        if subscribed
+          @$(".dogear").addClass("is-followed")
         else
-          selector.enable.apply(@)
-
-  abilityRenderer:
-    editable:
-      enable: -> @$(".action-edit").closest("li").show()
-      disable: -> @$(".action-edit").closest("li").hide()
-    can_delete:
-      enable: -> @$(".action-delete").closest("li").show()
-      disable: -> @$(".action-delete").closest("li").hide()
-    can_endorse:
-      enable: -> @$(".action-endorse").css("cursor", "auto")
-      disable: -> @$(".action-endorse").css("cursor", "default")
-    can_openclose:
-      enable: -> @$(".action-openclose").closest("li").show()
-      disable: -> @$(".action-openclose").closest("li").hide()
-
-  renderPartialAttrs: ->
-    for attr, value of @model.changedAttributes()
-      if @attrRenderer[attr]
-        @attrRenderer[attr].apply(@, [value])
-
-  renderAttrs: ->
-    for attr, value of @model.attributes
-      if @attrRenderer[attr]
-        @attrRenderer[attr].apply(@, [value])
-
-  $: (selector) ->
-    @$local.find(selector)
-
-  initLocal: ->
-    @$local = @$el.children(".local")
-    if not @$local.length
-      @$local = @$el
-    @$delegateElement = @$local
-
-  makeWmdEditor: (cls_identifier) =>
-    if not @$el.find(".wmd-panel").length
-      DiscussionUtil.makeWmdEditor @$el, $.proxy(@$, @), cls_identifier
-
-  getWmdEditor: (cls_identifier) =>
-    DiscussionUtil.getWmdEditor @$el, $.proxy(@$, @), cls_identifier
-
-  getWmdContent: (cls_identifier) =>
-    DiscussionUtil.getWmdContent @$el, $.proxy(@$, @), cls_identifier
-
-  setWmdContent: (cls_identifier, text) =>
-    DiscussionUtil.setWmdContent @$el, $.proxy(@$, @), cls_identifier, text
-
-  initialize: ->
-    @initLocal()
-    @model.bind('change', @renderPartialAttrs, @)
+          @$(".dogear").removeClass("is-followed")
+
+      ability: (ability) ->
+        for action, selector of @abilityRenderer
+          if not ability[action]
+            selector.disable.apply(@)
+          else
+            selector.enable.apply(@)
+
+    abilityRenderer:
+      editable:
+        enable: -> @$(".action-edit").closest("li").show()
+        disable: -> @$(".action-edit").closest("li").hide()
+      can_delete:
+        enable: -> @$(".action-delete").closest("li").show()
+        disable: -> @$(".action-delete").closest("li").hide()
+      can_endorse:
+        enable: -> @$(".action-endorse").css("cursor", "auto")
+        disable: -> @$(".action-endorse").css("cursor", "default")
+      can_openclose:
+        enable: -> @$(".action-openclose").closest("li").show()
+        disable: -> @$(".action-openclose").closest("li").hide()
+
+    renderPartialAttrs: ->
+      for attr, value of @model.changedAttributes()
+        if @attrRenderer[attr]
+          @attrRenderer[attr].apply(@, [value])
+
+    renderAttrs: ->
+      for attr, value of @model.attributes
+        if @attrRenderer[attr]
+          @attrRenderer[attr].apply(@, [value])
+
+    $: (selector) ->
+      @$local.find(selector)
+
+    initLocal: ->
+      @$local = @$el.children(".local")
+      if not @$local.length
+        @$local = @$el
+      @$delegateElement = @$local
+
+    makeWmdEditor: (cls_identifier) =>
+      if not @$el.find(".wmd-panel").length
+        DiscussionUtil.makeWmdEditor @$el, $.proxy(@$, @), cls_identifier
+
+    getWmdEditor: (cls_identifier) =>
+      DiscussionUtil.getWmdEditor @$el, $.proxy(@$, @), cls_identifier
+
+    getWmdContent: (cls_identifier) =>
+      DiscussionUtil.getWmdContent @$el, $.proxy(@$, @), cls_identifier
+
+    setWmdContent: (cls_identifier, text) =>
+      DiscussionUtil.setWmdContent @$el, $.proxy(@$, @), cls_identifier, text
+
+    initialize: ->
+      @initLocal()
+      @model.bind('change', @renderPartialAttrs, @)

lms/static/coffee/src/discussion/views/discussion_thread_view.coffee

-class @DiscussionThreadView extends DiscussionContentView
+if Backbone?
+  class @DiscussionThreadView extends DiscussionContentView
 
-  events:
-    "click .discussion-submit-post": "submitComment"
+    events:
+      "click .discussion-submit-post": "submitComment"
 
-  template: _.template($("#thread-template").html())
+    template: _.template($("#thread-template").html())
 
-  $: (selector) ->
-    @$el.find(selector)
+    $: (selector) ->
+      @$el.find(selector)
 
-  initialize: ->
-    super()
-    @showView = new DiscussionThreadShowView(model: @model)
-    @showView.bind "thread:delete", @delete
-    @showView.bind "thread:edit", @edit
+    initialize: ->
+      super()
+      @showView = new DiscussionThreadShowView(model: @model)
+      @showView.bind "thread:delete", @delete
+      @showView.bind "thread:edit", @edit
 
-  render: ->
-    @$el.html(@template(@model.toJSON()))
-    @delegateEvents()
+    render: ->
+      @$el.html(@template(@model.toJSON()))
+      @delegateEvents()
 
-    @showView.setElement(@$('.thread-content-wrapper'))
-    @showView.render()
-    @showView.delegateEvents()
+      @showView.setElement(@$('.thread-content-wrapper'))
+      @showView.render()
+      @showView.delegateEvents()
 
-    @renderAttrs()
-    @$("span.timeago").timeago()
-    @makeWmdEditor "reply-body"
-    @renderResponses()
-    @
+      @renderAttrs()
+      @$("span.timeago").timeago()
+      @makeWmdEditor "reply-body"
+      @renderResponses()
+      @
 
-  renderResponses: ->
-    DiscussionUtil.safeAjax
-      url: "/courses/#{$$course_id}/discussion/forum/#{@model.get('commentable_id')}/threads/#{@model.id}"
-      success: (data, textStatus, xhr) =>
-        @$el.find(".loading").remove()
-        Content.loadContentInfos(data['annotated_content_info'])
-        comments = new Comments(data['content']['children'])
-        comments.each @renderResponse
-        @trigger "thread:responses:rendered"
+    renderResponses: ->
+      DiscussionUtil.safeAjax
+        url: "/courses/#{$$course_id}/discussion/forum/#{@model.get('commentable_id')}/threads/#{@model.id}"
+        success: (data, textStatus, xhr) =>
+          @$el.find(".loading").remove()
+          Content.loadContentInfos(data['annotated_content_info'])
+          comments = new Comments(data['content']['children'])
+          comments.each @renderResponse
+          @trigger "thread:responses:rendered"
 
-  renderResponse: (response) =>
-      response.set('thread', @model)
-      view = new ThreadResponseView(model: response)
-      view.on "comment:add", @addComment
-      view.on "comment:endorse", @endorseThread
-      view.render()
-      @$el.find(".responses").append(view.el)
+    renderResponse: (response) =>
+        response.set('thread', @model)
+        view = new ThreadResponseView(model: response)
+        view.on "comment:add", @addComment
+        view.on "comment:endorse", @endorseThread
+        view.render()
+        @$el.find(".responses").append(view.el)
 
-  addComment: =>
-    @model.comment()
+    addComment: =>
+      @model.comment()
 
-  endorseThread: (endorsed) =>
-    is_endorsed = @$el.find(".is-endorsed").length
-    @model.set 'endorsed', is_endorsed
+    endorseThread: (endorsed) =>
+      is_endorsed = @$el.find(".is-endorsed").length
+      @model.set 'endorsed', is_endorsed
 
-  submitComment: (event) ->
-    event.preventDefault()
-    url = @model.urlFor('reply')
-    body = @getWmdContent("reply-body")
-    return if not body.trim().length
-    @setWmdContent("reply-body", "")
-    comment = new Comment(body: body, created_at: (new Date()).toISOString(), username: window.user.get("username"), votes: { up_count: 0 }, endorsed: false, user_id: window.user.get("id"))
-    comment.set('thread', @model.get('thread'))
-    @renderResponse(comment)
-    @model.addComment()
+    submitComment: (event) ->
+      event.preventDefault()
+      url = @model.urlFor('reply')
+      body = @getWmdContent("reply-body")
+      return if not body.trim().length
+      @setWmdContent("reply-body", "")
+      comment = new Comment(body: body, created_at: (new Date()).toISOString(), username: window.user.get("username"), votes: { up_count: 0 }, endorsed: false, user_id: window.user.get("id"))
+      comment.set('thread', @model.get('thread'))
+      @renderResponse(comment)
+      @model.addComment()
 
-    DiscussionUtil.safeAjax
-      $elem: $(event.target)
-      url: url
-      type: "POST"
-      dataType: 'json'
-      data:
-        body: body
-      success: (data, textStatus) =>
-        comment.updateInfo(data.annotated_content_info)
-        comment.set(data.content)
+      DiscussionUtil.safeAjax
+        $elem: $(event.target)
+        url: url
+        type: "POST"
+        dataType: 'json'
+        data:
+          body: body
+        success: (data, textStatus) =>
+          comment.updateInfo(data.annotated_content_info)
+          comment.set(data.content)
 
-  edit: ->
+    edit: ->
 
-  delete: (event) ->
-    url = @model.urlFor('delete')
-    if not @model.can('can_delete')
-      return
-    if not confirm "Are you sure to delete thread \"#{@model.get('title')}\"?"
-      return
-    @model.remove()
-    @$el.empty()
-    $elem = $(event.target)
-    DiscussionUtil.safeAjax
-      $elem: $elem
-      url: url
-      type: "POST"
-      success: (response, textStatus) =>
+    delete: (event) ->
+      url = @model.urlFor('delete')
+      if not @model.can('can_delete')
+        return
+      if not confirm "Are you sure to delete thread \"#{@model.get('title')}\"?"
+        return
+      @model.remove()
+      @$el.empty()
+      $elem = $(event.target)
+      DiscussionUtil.safeAjax
+        $elem: $elem
+        url: url
+        type: "POST"
+        success: (response, textStatus) =>

lms/static/coffee/src/discussion/views/new_post_inline_vew.coffee

-class @NewPostInlineView extends Backbone.View
-
-  initialize: () ->
-
-    @topicId    = @$(".topic").first().data("discussion-id")
-
-    @maxNameWidth = 100
-
-    DiscussionUtil.makeWmdEditor @$el, $.proxy(@$, @), "new-post-body"
-    @$(".new-post-tags").tagsInput DiscussionUtil.tagsInputOptions()
-
-  events:
-    "submit .new-post-form":            "createPost"
-
-  # Because we want the behavior that when the body is clicked the menu is
-  # closed, we need to ignore clicks in the search field and stop propagation.
-  # Without this, clicking the search field would also close the menu.
-  ignoreClick: (event) ->
-    event.stopPropagation()
-
-  createPost: (event) ->
-    event.preventDefault()
-    title   = @$(".new-post-title").val()
-    body    = @$(".new-post-body").find(".wmd-input").val()
-    tags    = @$(".new-post-tags").val()
-
-    anonymous = false || @$("input.discussion-anonymous").is(":checked")
-    follow    = false || @$("input.discussion-follow").is(":checked")
-
-    url = DiscussionUtil.urlFor('create_thread', @topicId)
-
-    DiscussionUtil.safeAjax
-      $elem: $(event.target)
-      $loading: $(event.target) if event
-      url: url
-      type: "POST"
-      dataType: 'json'
-      async: false # TODO when the rest of the stuff below is made to work properly..
-      data:
-        title: title
-        body: body
-        tags: tags
-        anonymous: anonymous
-        auto_subscribe: follow
-      error: DiscussionUtil.formErrorHandler(@$(".new-post-form-errors"))
-      success: (response, textStatus) =>
-        # TODO: Move this out of the callback, this makes it feel sluggish
-        thread = new Thread response['content']
-        DiscussionUtil.clearFormErrors(@$(".new-post-form-errors"))
-        @$el.hide()
-        @$(".new-post-title").val("").attr("prev-text", "")
-        @$(".new-post-body textarea").val("").attr("prev-text", "")
-        @$(".new-post-tags").val("")
-        @$(".new-post-tags").importTags("")
-        @collection.add thread
+if Backbone?
+  class @NewPostInlineView extends Backbone.View
+
+    initialize: () ->
+
+      @topicId    = @$(".topic").first().data("discussion-id")
+
+      @maxNameWidth = 100
+
+      DiscussionUtil.makeWmdEditor @$el, $.proxy(@$, @), "new-post-body"
+      @$(".new-post-tags").tagsInput DiscussionUtil.tagsInputOptions()
+
+    events:
+      "submit .new-post-form":            "createPost"
+
+    # Because we want the behavior that when the body is clicked the menu is
+    # closed, we need to ignore clicks in the search field and stop propagation.
+    # Without this, clicking the search field would also close the menu.
+    ignoreClick: (event) ->
+      event.stopPropagation()
+
+    createPost: (event) ->
+      event.preventDefault()
+      title   = @$(".new-post-title").val()
+      body    = @$(".new-post-body").find(".wmd-input").val()
+      tags    = @$(".new-post-tags").val()
+
+      anonymous = false || @$("input.discussion-anonymous").is(":checked")
+      follow    = false || @$("input.discussion-follow").is(":checked")
+
+      url = DiscussionUtil.urlFor('create_thread', @topicId)
+
+      DiscussionUtil.safeAjax
+        $elem: $(event.target)
+        $loading: $(event.target) if event
+        url: url
+        type: "POST"
+        dataType: 'json'
+        async: false # TODO when the rest of the stuff below is made to work properly..
+        data:
+          title: title
+          body: body
+          tags: tags
+          anonymous: anonymous
+          auto_subscribe: follow
+        error: DiscussionUtil.formErrorHandler(@$(".new-post-form-errors"))
+        success: (response, textStatus) =>
+          # TODO: Move this out of the callback, this makes it feel sluggish
+          thread = new Thread response['content']
+          DiscussionUtil.clearFormErrors(@$(".new-post-form-errors"))
+          @$el.hide()
+          @$(".new-post-title").val("").attr("prev-text", "")
+          @$(".new-post-body textarea").val("").attr("prev-text", "")
+          @$(".new-post-tags").val("")
+          @$(".new-post-tags").importTags("")
+          @collection.add thread

lms/static/coffee/src/discussion/views/response_comment_view.coffee

-class @ResponseCommentView extends DiscussionContentView
-  tagName: "li"
-  template: _.template($("#response-comment-template").html())
-  initLocal: ->
-    # TODO .response-local is the parent of the comments so @$local is null, not sure what was intended here...
-    @$local = @$el.find(".response-local")
-    @$delegateElement = @$local
+if Backbone?
+  class @ResponseCommentView extends DiscussionContentView
+    tagName: "li"
+    template: _.template($("#response-comment-template").html())
+    initLocal: ->
+      # TODO .response-local is the parent of the comments so @$local is null, not sure what was intended here...
+      @$local = @$el.find(".response-local")
+      @$delegateElement = @$local
 
-  render: ->
-    @$el.html(@template(@model.toJSON()))
-    @initLocal()
-    @delegateEvents()
-    @renderAttrs()
-    @$el.find(".timeago").timeago()
-    @convertMath()
-    @
-  convertMath: ->
-    body = @$el.find(".response-body")
-    body.html DiscussionUtil.postMathJaxProcessor DiscussionUtil.markdownWithHighlight body.html()
-    # This removes paragraphs so that comments are more compact
-    body.children("p").each (index, elem) ->
-      $(elem).replaceWith($(elem).html())
-    MathJax.Hub.Queue ["Typeset", MathJax.Hub, body[0]]
+    render: ->
+      @$el.html(@template(@model.toJSON()))
+      @initLocal()
+      @delegateEvents()
+      @renderAttrs()
+      @$el.find(".timeago").timeago()
+      @convertMath()
+      @
+    convertMath: ->
+      body = @$el.find(".response-body")
+      body.html DiscussionUtil.postMathJaxProcessor DiscussionUtil.markdownWithHighlight body.html()
+      # This removes paragraphs so that comments are more compact
+      body.children("p").each (index, elem) ->
+        $(elem).replaceWith($(elem).html())
+      MathJax.Hub.Queue ["Typeset", MathJax.Hub, body[0]]

lms/static/coffee/src/discussion/views/thread_response_view.coffee

-class @ThreadResponseView extends DiscussionContentView
-  tagName: "li"
-  template: _.template($("#thread-response-template").html())
+if Backbone?
+  class @ThreadResponseView extends DiscussionContentView
+    tagName: "li"
+    template: _.template($("#thread-response-template").html())
 
-  events:
-      "click .vote-btn": "toggleVote"
-      "submit .comment-form": "submitComment"
-      "click .action-endorse": "toggleEndorse"
-      "click .action-delete": "delete"
+    events:
+        "click .vote-btn": "toggleVote"
+        "submit .comment-form": "submitComment"
+        "click .action-endorse": "toggleEndorse"
+        "click .action-delete": "delete"
 
-  render: ->
-    @$el.html(@template(@model.toJSON()))
-    @initLocal()
-    @delegateEvents()
-    if window.user.voted(@model)
-      @$(".vote-btn").addClass("is-cast")
-    @renderAttrs()
-    @$el.find(".posted-details").timeago()
-    @convertMath()
-    @renderComments()
-    @
+    render: ->
+      @$el.html(@template(@model.toJSON()))
+      @initLocal()
+      @delegateEvents()
+      if window.user.voted(@model)
+        @$(".vote-btn").addClass("is-cast")
+      @renderAttrs()
+      @$el.find(".posted-details").timeago()
+      @convertMath()
+      @renderComments()
+      @
 
-  convertMath: ->
-    element = @$(".response-body")
-    element.html DiscussionUtil.postMathJaxProcessor DiscussionUtil.markdownWithHighlight element.html()
-    MathJax.Hub.Queue ["Typeset", MathJax.Hub, element[0]]
+    convertMath: ->
+      element = @$(".response-body")
+      element.html DiscussionUtil.postMathJaxProcessor DiscussionUtil.markdownWithHighlight element.html()
+      MathJax.Hub.Queue ["Typeset", MathJax.Hub, element[0]]
 
-  renderComments: ->
-    @model.get("comments").each @renderComment
+    renderComments: ->
+      @model.get("comments").each @renderComment
 
-  renderComment: (comment) =>
-    comment.set('thread', @model.get('thread'))
-    view = new ResponseCommentView(model: comment)
-    view.render()
-    @$el.find(".comments li:last").before(view.el)
+    renderComment: (comment) =>
+      comment.set('thread', @model.get('thread'))
+      view = new ResponseCommentView(model: comment)
+      view.render()
+      @$el.find(".comments li:last").before(view.el)
 
-  toggleVote: (event) ->
-    event.preventDefault()
-    @$(".vote-btn").toggleClass("is-cast")
-    if @$(".vote-btn").hasClass("is-cast")
-      @vote()
-    else
-      @unvote()
+    toggleVote: (event) ->
+      event.preventDefault()
+      @$(".vote-btn").toggleClass("is-cast")
+      if @$(".vote-btn").hasClass("is-cast")
+        @vote()
+      else
+        @unvote()
 
-  vote: ->
-    url = @model.urlFor("upvote")
-    @$(".votes-count-number").html(parseInt(@$(".votes-count-number").html()) + 1)
-    DiscussionUtil.safeAjax
-      $elem: @$(".discussion-vote")
-      url: url
-      type: "POST"
-      success: (response, textStatus) =>
-        if textStatus == 'success'
-          @model.set(response)
+    vote: ->
+      url = @model.urlFor("upvote")
+      @$(".votes-count-number").html(parseInt(@$(".votes-count-number").html()) + 1)
+      DiscussionUtil.safeAjax
+        $elem: @$(".discussion-vote")
+        url: url
+        type: "POST"
+        success: (response, textStatus) =>
+          if textStatus == 'success'
+            @model.set(response)
 
-  unvote: ->
-    url = @model.urlFor("unvote")
-    @$(".votes-count-number").html(parseInt(@$(".votes-count-number").html()) - 1)
-    DiscussionUtil.safeAjax
-      $elem: @$(".discussion-vote")
-      url: url
-      type: "POST"
-      success: (response, textStatus) =>
-        if textStatus == 'success'
-          @model.set(response)
+    unvote: ->
+      url = @model.urlFor("unvote")
+      @$(".votes-count-number").html(parseInt(@$(".votes-count-number").html()) - 1)
+      DiscussionUtil.safeAjax
+        $elem: @$(".discussion-vote")
+        url: url
+        type: "POST"
+        success: (response, textStatus) =>
+          if textStatus == 'success'
+            @model.set(response)
 
-  submitComment: (event) ->
-    event.preventDefault()
-    url = @model.urlFor('reply')
-    body = @$(".comment-form-input").val()
-    if not body.trim().length
-      return
-    comment = new Comment(body: body, created_at: (new Date()).toISOString(), username: window.user.get("username"), user_id: window.user.get("id"))
-    @renderComment(comment)
-    @trigger "comment:add", comment
-    @$(".comment-form-input").val("")
+    submitComment: (event) ->
+      event.preventDefault()
+      url = @model.urlFor('reply')
+      body = @$(".comment-form-input").val()
+      if not body.trim().length
+        return
+      comment = new Comment(body: body, created_at: (new Date()).toISOString(), username: window.user.get("username"), user_id: window.user.get("id"))
+      @renderComment(comment)
+      @trigger "comment:add", comment
+      @$(".comment-form-input").val("")
 
-    DiscussionUtil.safeAjax
-      $elem: $(event.target)
-      url: url
-      type: "POST"
-      dataType: 'json'
-      data:
-        body: body
+      DiscussionUtil.safeAjax
+        $elem: $(event.target)
+        url: url
+        type: "POST"
+        dataType: 'json'
+        data:
+          body: body
 
-  delete: (event) ->
-    event.preventDefault()
-    if not @model.can('can_delete')
-      return
-    console.log $(event.target)
-    url = @model.urlFor('delete')
-    if not confirm "Are you sure to delete this response? "
-      return
-    @model.remove()
-    @$el.remove()
-    $elem = $(event.target)
-    DiscussionUtil.safeAjax
-      $elem: $elem
-      url: url
-      type: "POST"
-      success: (response, textStatus) =>
+    delete: (event) ->
+      event.preventDefault()
+      if not @model.can('can_delete')
+        return
+      console.log $(event.target)
+      url = @model.urlFor('delete')
+      if not confirm "Are you sure to delete this response? "
+        return
+      @model.remove()
+      @$el.remove()
+      $elem = $(event.target)
+      DiscussionUtil.safeAjax
+        $elem: $elem
+        url: url
+        type: "POST"
+        success: (response, textStatus) =>
 
-  toggleEndorse: (event) ->
-    event.preventDefault()
-    if not @model.can('can_endorse')
-      return
-    $elem = $(event.target)
-    url = @model.urlFor('endorse')
-    endorsed = @model.get('endorsed')
-    data = { endorsed: not endorsed }
-    @model.set('endorsed', not endorsed)
-    @trigger "comment:endorse", not endorsed
-    DiscussionUtil.safeAjax
-      $elem: $elem
-      url: url
-      data: data
-      type: "POST"
+    toggleEndorse: (event) ->
+      event.preventDefault()
+      if not @model.can('can_endorse')
+        return
+      $elem = $(event.target)
+      url = @model.urlFor('endorse')
+      endorsed = @model.get('endorsed')
+      data = { endorsed: not endorsed }
+      @model.set('endorsed', not endorsed)
+      @trigger "comment:endorse", not endorsed
+      DiscussionUtil.safeAjax
+        $elem: $elem
+        url: url
+        data: data
+        type: "POST"