Pass item to render method of RosterView instead of looping over each item on...

Pass item to render method of RosterView instead of looping over each item on every render call, Inverted visibility logic for contact titles in order to avoid multiple show and hide

converse.js

@@ -1537,16 +1537,16 @@
                         this.model.remove(item.id);
                     }, this);
                 }
-                this.render();
+                this.render(item);
             }, this);
 
             this.model.on('change', function (item) {
-                this.render();
+                this.render(item);
             }, this);
 
             this.model.on("remove", function (item) {
                 delete this.rosteritemviews[item.id];
-                this.render();
+                this.render(item);
             }, this);
 
             this.$el.html(this.template());
@@ -1556,20 +1556,19 @@
                             '<dt id="xmpp-contacts">My contacts</dt>' +
                             '<dt id="pending-xmpp-contacts">Pending contacts</dt>'),
 
-        render: function () {
-            var models = this.model.sort().models,
-                children = $(this.el).children(),
-                $my_contacts = this.$el.find('#xmpp-contacts').hide(),
-                $contact_requests = this.$el.find('#xmpp-contact-requests').hide(),
-                $pending_contacts = this.$el.find('#pending-xmpp-contacts').hide(),
+        render: function (item) {
+            if (!item) {
+                return this;
+            }
+            var
+                $my_contacts = this.$el.find('#xmpp-contacts').show(),
+                $contact_requests = this.$el.find('#xmpp-contact-requests').show(),
+                $pending_contacts = this.$el.find('#pending-xmpp-contacts').show(),
                 $count, num;
-
-            for (var i=0; i<models.length; i++) {
-                var model = models[i],
-                    user_id = Strophe.getNodeFromJid(model.id),
-                    view = this.rosteritemviews[model.id],
-                    ask = model.get('ask'),
-                    subscription = model.get('subscription'),
+            var user_id = Strophe.getNodeFromJid(item.id),
+                    view = this.rosteritemviews[item.id],
+                    ask = item.get('ask'),
+                    subscription = item.get('subscription'),
                     crit = {order:'asc'};
 
                 if (ask === 'subscribe') {
@@ -1586,11 +1585,10 @@
                     $my_contacts.after($my_contacts.siblings('dd.current-xmpp-contact.busy').tsort('a', crit));
                     $my_contacts.after($my_contacts.siblings('dd.current-xmpp-contact.online').tsort('a', crit));
                 } 
-            }
             // Hide the headings if there are no contacts under them
             _.each([$my_contacts, $contact_requests, $pending_contacts], function (h) {
-                if (h.nextUntil('dt').length > 0) {
-                    h.show();
+                if (!h.nextUntil('dt').length) {
+                    h.hide();
                 }
             });
             $count = $('#online-count');