dont search empty string, get 20 tags instead of 10

public/src/client/tags.js

@@ -14,6 +14,11 @@ define('forum/tags', ['forum/infinitescroll'], function(infinitescroll) {
 				clearTimeout(timeoutId);
 				timeoutId = 0;
 			}
+
+			if (!$('#tag-search').val().length) {
+				return;
+			}
+
 			timeoutId = setTimeout(function() {
 				socket.emit('topics.searchAndLoadTags', {query: $('#tag-search').val()}, function(err, results) {
 					if (err) {

src/socket.io/topics.js

@@ -521,6 +521,12 @@ SocketTopics.search = function(socket, data, callback) {
 };
 
 SocketTopics.searchAndLoadTags = function(socket, data, callback) {
+	if (!data) {
+		return callback(new Error('[[error:invalid-data]]'));
+	}
+	if (!data.query || !data.query.length) {
+		return callback(null, []);
+	}
 	topics.searchTags(data, function(err, tags) {
 		if (err) {
 			return callback(err);

src/topics/tags.js

@@ -222,14 +222,15 @@ module.exports = function(Topics) {
 				return callback(null, tags);
 			}
 			data.query = data.query.toLowerCase();
+
 			var matches = [];
 			for(var i=0; i<tags.length; ++i) {
-				if (tags[i].toLowerCase().indexOf(data.query) === 0) {
+				if (tags[i].toLowerCase().startsWith(data.query)) {
 					matches.push(tags[i]);
 				}
 			}
 
-			matches = matches.slice(0, 10).sort(function(a, b) {
+			matches = matches.slice(0, 20).sort(function(a, b) {
 				return a > b;
 			});