Redo how rendering of list items is done. Better memory, faster rendering.

lms/static/coffee/src/discussion/content.coffee

@@ -454,19 +454,17 @@ if Backbone?
 
     follow: ->
       @set('subscribed', true)
-      @trigger "thread:follow"
 
     unfollow: ->
       @set('subscribed', false)
-      @trigger "thread:unfollow"
 
     vote: ->
       @get("votes")["up_count"] = parseInt(@get("votes")["up_count"]) + 1
-      @trigger "change"
+      @trigger "change", @
 
     unvote: ->
       @get("votes")["up_count"] = parseInt(@get("votes")["up_count"]) - 1
-      @trigger "change"
+      @trigger "change", @
 
     display_body: ->
       if @has("highlighted_body")

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

@@ -7,6 +7,7 @@ class @DiscussionThreadListView extends Backbone.View
     "click .sort-bar a": "sortThreads"
     "click .browse-topic-drop-menu": "filterTopic"
     "click .browse-topic-drop-search-input": "ignoreClick"
+    "click .post-list a": "threadSelected"
 
   initialize: ->
     @displayedCollection = new Discussion(@collection.models)
@@ -14,9 +15,14 @@ class @DiscussionThreadListView extends Backbone.View
     @sidebar_padding = 10
     @sidebar_header_height = 87
 
-  reloadDisplayedCollection: =>
-    @displayedCollection.reset(@collection.models)
-    @updateSidebar()
+  reloadDisplayedCollection: (thread) =>
+    thread_id = thread.get('id')
+    content = @renderThread(thread)
+    current_el = @$("a[data-id=#{thread_id}]")
+    active = current_el.hasClass("active")
+    current_el.replaceWith(content)
+    if active
+      @setActiveThread(thread_id)
 
   updateSidebar: =>
 
@@ -71,9 +77,25 @@ class @DiscussionThreadListView extends Backbone.View
 
   renderThreads: =>
     @$(".post-list").html("")
-    @displayedCollection.each @renderThreadListItem
+    rendered = $("<div></div>")
+    for thread in @displayedCollection.models
+      content = @renderThread(thread)
+      rendered.append content
+      content.wrap("<li data-id='#{thread.get('id')}' />")
+
+    @$(".post-list").html(rendered.html())
     @trigger "threads:rendered"
 
+  renderThread: (thread) =>
+    content = $(_.template($("#thread-list-item-template").html())(thread.toJSON()))
+    if thread.get('subscribed')
+      content.addClass("followed")
+    @highlight(content)
+
+
+  highlight: (el) ->
+    el.html(el.html().replace(/&lt;mark&gt;/g, "<mark>").replace(/&lt;\/mark&gt;/g, "</mark>"))
+
   renderThreadListItem: (thread) =>
     view = new ThreadListItemView(model: thread)
     view.on "thread:selected", @threadSelected
@@ -81,15 +103,17 @@ class @DiscussionThreadListView extends Backbone.View
     view.render()
     @$(".post-list").append(view.el)
 
-  threadSelected: (thread_id) =>
+  threadSelected: (e) =>
+    thread_id = $(e.target).closest("a").data("id")
     @setActiveThread(thread_id)
     @trigger("thread:selected", thread_id)
+    false
 
   threadRemoved: (thread_id) =>
     @trigger("thread:removed", thread_id)
 
   setActiveThread: (thread_id) ->
-    @$(".post-list a").removeClass("active")
+    @$("a[data-id!='#{thread_id}']").removeClass("active")
     @$("a[data-id='#{thread_id}']").addClass("active")
 
   showSearch: ->
@@ -175,7 +199,7 @@ class @DiscussionThreadListView extends Backbone.View
     firstShownIndex = $($(".browse-topic-drop-menu-wrapper a").not('.hidden')[0]).parent().index()
 
     if event.which == 40
-      index = index + 1      
+      index = index + 1
     else if event.which == 38
       index = index - 1
       while $(".browse-topic-drop-menu-wrapper li").eq(index).find('a').hasClass('hidden')
@@ -189,5 +213,3 @@ class @DiscussionThreadListView extends Backbone.View
     $(".browse-topic-drop-menu-wrapper .focused").removeClass("focused")
     $(".browse-topic-drop-menu-wrapper li").eq(index).find('a').addClass("focused")
     $(".browse-topic-drop-menu-wrapper").attr("data-focused", index)
-
-

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

@@ -103,7 +103,7 @@ class @DiscussionThreadView extends DiscussionContentView
       type: "POST"
       success: (response, textStatus) =>
         if textStatus == 'success'
-          @model.set(response)
+          @model.set(response, {silent: true})
 
   unvote: ->
     window.user.unvote(@model)
@@ -114,7 +114,7 @@ class @DiscussionThreadView extends DiscussionContentView
       type: "POST"
       success: (response, textStatus) =>
         if textStatus == 'success'
-          @model.set(response)
+          @model.set(response, {silent: true})
 
   submitComment: (event) ->
     event.preventDefault()

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

-class @ThreadListItemView extends Backbone.View
-  tagName: "li"
-  template: _.template($("#thread-list-item-template").html())
-
-  events:
-    "click a": "threadSelected"
-
-  initialize: ->
-    @model.on "change", @render
-    @model.on "thread:remove", @threadRemoved
-    @model.on "thread:follow", @follow
-    @model.on "thread:unfollow", @unfollow
-    @model.on "comment:add", @addComment
-    @model.on "comment:remove", @removeComment
-
-  render: =>
-    @$el.html(@template(@model.toJSON()))
-    if window.user.following(@model)
-      @follow()
-    @highlight @$(".title")
-    @
-
-  threadSelected: (event) ->
-    event.preventDefault()
-    @trigger("thread:selected", @model.id)
-
-  threadRemoved: =>
-    @trigger("thread:removed", @model.id)
-
-  follow: =>
-    @$("a").addClass("followed")
-
-  unfollow: =>
-    @$("a").removeClass("followed")
-
-  addComment: (comment) =>
-    @$(".comments-count").html(@model.get('comments_count'))
-
-  removeComment: (comment) =>
-    @$(".comments-count").html(@model.get('comments_count'))
-
-  #addComment: =>
-  #  @$(".comments-count").html(parseInt(@$(".comments-count").html()) + 1)
-
-  highlight: (el) ->
-    el.html(el.html().replace(/&lt;mark&gt;/g, "<mark>").replace(/&lt;\/mark&gt;/g, "</mark>"))