Handle case where chat content is empty

src/converse-muc-views.js

@@ -1429,11 +1429,11 @@
                 showLeaveNotification (occupant) {
                     const nick = occupant.get('nick'),
                           stat = occupant.get('status'),
-                          last_el = this.content.lastElementChild,
-                          last_msg_date = last_el.getAttribute('data-isodate');
+                          last_el = this.content.lastElementChild;
 
-                    if (_.includes(_.get(last_el, 'classList', []), 'chat-info') &&
-                            moment(last_msg_date).isSame(new Date(), "day") &&
+                    if (last_el &&
+                            _.includes(_.get(last_el, 'classList', []), 'chat-info') &&
+                            moment(last_el.getAttribute('data-isodate')).isSame(new Date(), "day") &&
                             _.get(last_el, 'dataset', {}).join === `"${nick}"`) {
 
                         let message;
@@ -1462,7 +1462,8 @@
                             'extra_classes': 'chat-event',
                             'data': `data-leave="${nick}"`
                         }
-                        if (_.includes(_.get(last_el, 'classList', []), 'chat-info') &&
+                        if (last_el &&
+                            _.includes(_.get(last_el, 'classList', []), 'chat-info') &&
                             _.get(last_el, 'dataset', {}).leavejoin === `"${nick}"`) {
 
                             last_el.outerHTML = tpl_info(data);