Fixed error being thrown by ChannelHeader when switching teams (#4619)

* Fixed error being thrown by ChannelHeader when switching teams

* Close SidebarHeaderDropdown after switching teams

webapp/components/channel_header.jsx

@@ -69,7 +69,7 @@ export default class ChannelHeader extends React.Component {
         const users = UserStore.getProfileListInChannel(this.props.channelId);
 
         let otherUserId = null;
-        if (channel.type === 'D') {
+        if (channel && channel.type === 'D') {
             otherUserId = Utils.getUserIdFromChannelName(channel);
         }
 

webapp/components/sidebar_header_dropdown.jsx

@@ -45,6 +45,7 @@ export default class SidebarHeaderDropdown extends React.Component {
         this.showGetTeamInviteLinkModal = this.showGetTeamInviteLinkModal.bind(this);
         this.showTeamMembersModal = this.showTeamMembersModal.bind(this);
         this.hideTeamMembersModal = this.hideTeamMembersModal.bind(this);
+        this.handleSwitchTeams = this.handleSwitchTeams.bind(this);
 
         this.onTeamChange = this.onTeamChange.bind(this);
         this.openAccountSettings = this.openAccountSettings.bind(this);
@@ -131,6 +132,11 @@ export default class SidebarHeaderDropdown extends React.Component {
         });
     }
 
+    handleSwitchTeams() {
+        // The actual switching of teams is handled by the react-router Link
+        this.setState({showDropdown: false});
+    }
+
     componentDidMount() {
         TeamStore.addChangeListener(this.onTeamChange);
         document.addEventListener('keydown', this.openAccountSettings);
@@ -367,6 +373,7 @@ export default class SidebarHeaderDropdown extends React.Component {
                             <li key={'team_' + team.name}>
                                 <Link
                                     to={'/' + team.name + '/channels/town-square'}
+                                    onClick={this.handleSwitchTeams}
                                 >
                                     <FormattedMessage
                                         id='navbar_dropdown.switchTo'