Fix error message on leaving channel

web/react/stores/socket_store.jsx

@@ -160,7 +160,7 @@ function handleNewPostEvent(msg) {
         if (window.isActive) {
             AsyncClient.updateLastViewedAt(true);
         }
-    } else {
+    } else if (UserStore.getCurrentId() !== msg.user_id || post.type !== Constants.POST_TYPE_JOIN_LEAVE) {
         AsyncClient.getChannel(msg.channel_id);
     }
 

web/react/utils/async_client.jsx

@@ -132,7 +132,7 @@ export function getChannel(id) {
     callTracker['getChannel' + id] = utils.getTimestamp();
 
     client.getChannel(id,
-        function getChannelSuccess(data, textStatus, xhr) {
+        (data, textStatus, xhr) => {
             callTracker['getChannel' + id] = 0;
 
             if (xhr.status === 304 || !data) {
@@ -145,7 +145,7 @@ export function getChannel(id) {
                 member: data.member
             });
         },
-        function getChannelFailure(err) {
+        (err) => {
             callTracker['getChannel' + id] = 0;
             dispatchError(err, 'getChannel');
         }

web/react/utils/constants.jsx

@@ -98,6 +98,7 @@ module.exports = {
     POST_LOADING: 'loading',
     POST_FAILED: 'failed',
     POST_DELETED: 'deleted',
+    POST_TYPE_JOIN_LEAVE: 'join_leave',
     RESERVED_TEAM_NAMES: [
         'www',
         'web',