empty array if not topics in catgory

src/categories.js

@@ -93,23 +93,23 @@ var db = require('./database'),
 				topics.getTopicsByTids(tids, cid, uid, next);
 			},
 			function(topics, next) {
-				if (topics && topics.length > 0) {
-					db.sortedSetRevRank('categories:' + cid + ':tid', topics[topics.length - 1].tid, function(err, rank) {
-						if(err) {
-							return next(err);
-						}
-
-						next(null, {
-							topics: topics,
-							nextStart: parseInt(rank, 10) + 1
-						});
+				if (!topics || !topics.length) {
+					return next(null, {
+						topics: [],
+						nextStart: 1
 					});
-				} else {
+				}
+
+				db.sortedSetRevRank('categories:' + cid + ':tid', topics[topics.length - 1].tid, function(err, rank) {
+					if(err) {
+						return next(err);
+					}
+
 					next(null, {
 						topics: topics,
-						nextStart: 1
+						nextStart: parseInt(rank, 10) + 1
 					});
-				}
+				});
 			}
 		], callback);
 	};