FIX: Progress wasn't docking properly

app/assets/javascripts/discourse/models/post_stream.js

@@ -64,6 +64,15 @@ Discourse.PostStream = Em.Object.extend({
 
   firstPostNotLoaded: Em.computed.not('firstPostLoaded'),
 
+  /**
+    Returns the id of the last post in the set
+
+    @property lastPostId
+  **/
+  lastPostId: function() {
+    return _.last(this.get('stream'));
+  }.property('stream.@each'),
+
   /**
     Have we loaded the last post in the stream?
 
@@ -71,8 +80,8 @@ Discourse.PostStream = Em.Object.extend({
   **/
   lastPostLoaded: function() {
     if (!this.get('hasLoadedData')) { return false; }
-    return !!this.get('posts').findProperty('id', _.last(this.get('stream')));
+    return !!this.get('posts').findProperty('id', this.get('lastPostId'));
-  }.property('hasLoadedData', 'posts.[]', 'stream.@each'),
+  }.property('hasLoadedData', 'posts.[]', 'lastPostId'),
 
   lastPostNotLoaded: Em.computed.not('lastPostLoaded'),
 

app/assets/javascripts/discourse/templates/topic.js.handlebars

@@ -39,7 +39,7 @@
     <div class="row">
       <section class="topic-area" id='topic' data-topic-id='{{unbound id}}'>
         <div class='posts-wrapper'>
-          <div id='topic-progress-wrapper'>
+          <div id='topic-progress-wrapper' {{bindAttr class="dockedCounter:docked"}}>
             <nav id='topic-progress' title="{{i18n topic.progress.title}}" {{bindAttr class="hideProgress:hidden"}}>
               <button id='jump-top' title="{{i18n topic.progress.jump_top}}" {{bindAttr disabled="jumpTopDisabled"}} {{action jumpTop}}><i class="icon-circle-arrow-up"></i></button>
               <div class='nums'>

app/assets/javascripts/discourse/views/topic_view.js

@@ -162,9 +162,7 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
   },
 
   resetExamineDockCache: function() {
-    this.docAt = null;
+    this.set('docAt', false);
-    this.dockedTitle = false;
-    this.dockedCounter = false;
   },
 
   updateDock: function(postView) {
@@ -239,37 +237,25 @@ Discourse.TopicView = Discourse.View.extend(Discourse.Scrolling, {
     }
 
     var offset = window.pageYOffset || $('html').scrollTop();
-    var firstLoaded = topic.get('postStream.firstPostLoaded');
+    if (!this.get('docAt')) {
-    if (!this.docAt) {
       var title = $('#topic-title');
       if (title && title.length === 1) {
-        this.docAt = title.offset().top;
+        this.set('docAt', title.offset().top);
       }
     }
 
     var headerController = this.get('controller.controllers.header');
-    if (this.docAt) {
+    if (this.get('docAt')) {
-      headerController.set('showExtraInfo', offset >= this.docAt || !firstLoaded);
+      headerController.set('showExtraInfo', offset >= this.get('docAt') || topic.get('postStream.firstPostNotLoaded'));
     } else {
-      headerController.set('showExtraInfo', !firstLoaded);
+      headerController.set('showExtraInfo', topic.get('postStream.firstPostNotLoaded'));
     }
 
-    // there is a whole bunch of caching we could add here
+    // Dock the counter if necessary
-    var $lastPost = $('.last-post');
+    var $lastPost = $('article[data-post-id=' + topic.get('postStream.lastPostId') + "]");
     var lastPostOffset = $lastPost.offset();
-    if (!lastPostOffset) return;
+    if (!lastPostOffset) { return; }
-
+    this.set('controller.dockedCounter', (offset >= (lastPostOffset.top + $lastPost.height()) - $(window).height()));
-    if (offset >= (lastPostOffset.top + $lastPost.height()) - $(window).height()) {
-      if (!this.dockedCounter) {
-        $('#topic-progress-wrapper').addClass('docked');
-        this.dockedCounter = true;
-      }
-    } else {
-      if (this.dockedCounter) {
-        $('#topic-progress-wrapper').removeClass('docked');
-        this.dockedCounter = false;
-      }
-    }
   },
 
   topicTrackingState: function() {

test/javascripts/models/post_stream_test.js

@@ -22,6 +22,8 @@ test('defaults', function() {
 test('appending posts', function() {
   var postStream = buildStream(4567, [1, 3, 4]);
 
+  equal(postStream.get('lastPostId'), 4, "the last post id is 4");
+
   ok(!postStream.get('hasPosts'), "there are no posts by default");
   ok(!postStream.get('firstPostLoaded'), "the first post is not loaded");
   ok(!postStream.get('lastPostLoaded'), "the last post is not loaded");
@@ -29,7 +31,6 @@ test('appending posts', function() {
 
   postStream.appendPost(Discourse.Post.create({id: 2, post_number: 2}));
   ok(!postStream.get('firstPostLoaded'), "the first post is still not loaded");
-  ok(!postStream.get('lastPostLoaded'), "the last post is still not loaded");
   equal(postStream.get('posts.length'), 1, "it has one post in the stream");
 
   postStream.appendPost(Discourse.Post.create({id: 4, post_number: 4}));