closes #3227

src/categories/recentreplies.js

@@ -56,9 +56,10 @@ module.exports = function(Categories) {
 				}
 			},
 			function(posts, next) {
-				categoryData.forEach(function(category) {
-					assignPostsToCategory(category, posts);
-				});
+				assignPostsToCategories(categoryData, posts);
+
+				bubbleUpChildrenPosts(categoryData);
+
 				next();
 			}
 		], callback);
@@ -87,13 +88,33 @@ module.exports = function(Categories) {
 		], callback);
 	}
 
-	function assignPostsToCategory(category, posts) {
+	function bubbleUpChildrenPosts(categoryData) {
+		categoryData.forEach(function(category) {
+			if (category.posts.length) {
+				return;
+			}
+			var latestPost;
+			category.children.forEach(function(children) {
+				if (children.posts.length && (!latestPost || (latestPost && latestPost.timestamp < children.posts[0].timestamp))) {
+					latestPost = children.posts[0];
+				}
+			});
+
+			if (latestPost) {
+				category.posts = [latestPost];
+			}
+		});
+	}
+
+	function assignPostsToCategories(categories, posts) {
+		categories.forEach(function(category) {
 			category.posts = posts.filter(function(post) {
 				return post.category && (parseInt(post.category.cid, 10) === parseInt(category.cid, 10) ||
 					parseInt(post.category.parentCid, 10) === parseInt(category.cid, 10));
 			}).sort(function(a, b) {
 				return b.timestamp - a.timestamp;
 			}).slice(0, parseInt(category.numRecentReplies, 10));
+		});
 	}
 
 	function getRecentTopicPids(category, callback) {

src/controllers/categories.js

@@ -191,7 +191,9 @@ categoriesController.get = function(req, res, next) {
 			});
 		},
 		function(categoryData, next) {
-			categories.getRecentTopicReplies(categoryData.children, req.uid, function(err) {
+			var allCategories = [];
+			categories.flattenCategories(allCategories, [categoryData]);
+			categories.getRecentTopicReplies(allCategories, req.uid, function(err) {
 				next(err, categoryData);
 			});
 		},