faster getTeasers

got rid of getPostIndices

src/database/mongo/sorted.js

@@ -203,7 +203,7 @@ module.exports = function(db, module) {
 
 	module.sortedSetCard = function(key, callback) {
 		if (!key) {
-			return callback();
+			return callback(null, 0);
 		}
 		db.collection('objects').count({_key: key}, function(err, count) {
 			count = parseInt(count, 10);

src/topics.js

@@ -193,6 +193,9 @@ var async = require('async'),
 			var cids = mapFilter(topics, 'cid');
 
 			async.parallel({
+				teasers: function(next) {
+					Topics.getTeasers(tids, uid, next);
+				},
 				users: function(next) {
 					user.getMultipleUserFields(uids, ['uid', 'username', 'userslug', 'picture'], next);
 				},
@@ -205,9 +208,6 @@ var async = require('async'),
 				isAdminOrMod: function(next) {
 					privileges.categories.isAdminOrMod(cids, uid, next);
 				},
-				teasers: function(next) {
-					Topics.getTeasers(tids, uid, next);
-				},
 				tags: function(next) {
 					Topics.getTopicsTagsObjects(tids, next);
 				}
@@ -346,20 +346,29 @@ var async = require('async'),
 	};
 
 	Topics.getTeasers = function(tids, uid, callback) {
-		if(!Array.isArray(tids)) {
+		if(!Array.isArray(tids) || !tids.length) {
 			return callback(null, []);
 		}
 
+		async.parallel({
+			counts: function(next) {
+				async.map(tids, function(tid, next) {
+					db.sortedSetCard('tid:' + tid + ':posts', next);
+				}, next);
+			},
+			pids: function(next) {
 				async.map(tids, function(tid, next) {
 					db.getSortedSetRevRange('tid:' + tid + ':posts', 0, 0, function(err, data) {
 						next(err, Array.isArray(data) && data.length ? data[0] : null);
 					});
-		}, function(err, pids) {
+				}, next);
+			}
+		}, function(err, results) {
 			if (err) {
 				return callback(err);
 			}
 
-			var postKeys = pids.filter(Boolean).map(function(pid) {
+			var postKeys = results.pids.filter(Boolean).map(function(pid) {
 				return 'post:' + pid;
 			});
 
@@ -374,26 +383,20 @@ var async = require('async'),
 					return array.indexOf(uid) === index;
 				});
 
-				async.parallel({
-					users: function(next) {
-						user.getMultipleUserFields(uids, ['uid', 'username', 'userslug', 'picture'], next);
-					},
-					indices: function(next) {
-						posts.getPostIndices(postData, uid, next);
-					}
-				}, function(err, results) {
+
+				user.getMultipleUserFields(uids, ['uid', 'username', 'userslug', 'picture'], function(err, usersData) {
 					if (err) {
 						return callback(err);
 					}
 
 					var users = {};
-					results.users.forEach(function(user) {
+					usersData.forEach(function(user) {
 						users[user.uid] = user;
 					});
 					var tidToPost = {};
 					postData.forEach(function(post, index) {
 						post.user = users[post.uid];
-						post.index = results.indices[index] + 1;
+						post.index = results.counts[index] + 1;
 						post.timestamp = utils.toISOString(post.timestamp);
 						tidToPost[post.tid] = post;
 					});