Add option to opt out of unread notification markers (#15842)

Fixes #15133

app/javascript/mastodon/features/notifications/components/column_settings.js

@@ -55,6 +55,16 @@ export default class ColumnSettings extends React.PureComponent {
           <ClearColumnButton onClick={onClear} />
         </div>
 
+        <div role='group' aria-labelledby='notifications-unread-markers'>
+          <span id='notifications-unread-markers' className='column-settings__section'>
+            <FormattedMessage id='notifications.column_settings.unread_markers.category' defaultMessage='Unread notification markers' />
+          </span>
+
+          <div className='column-settings__row'>
+            <SettingToggle id='unread-notification-markers' prefix='notifications' settings={settings} settingPath={['showUnread']} onChange={onChange} label={filterShowStr} />
+          </div>
+        </div>
+
         <div role='group' aria-labelledby='notifications-filter-bar'>
           <span id='notifications-filter-bar' className='column-settings__section'>
             <FormattedMessage id='notifications.column_settings.filter_bar.category' defaultMessage='Quick filter bar' />

app/javascript/mastodon/features/notifications/index.js

@@ -60,8 +60,8 @@ const mapStateToProps = state => ({
   isUnread: state.getIn(['notifications', 'unread']) > 0 || state.getIn(['notifications', 'pendingItems']).size > 0,
   hasMore: state.getIn(['notifications', 'hasMore']),
   numPending: state.getIn(['notifications', 'pendingItems'], ImmutableList()).size,
-  lastReadId: state.getIn(['notifications', 'readMarkerId']),
-  canMarkAsRead: state.getIn(['notifications', 'readMarkerId']) !== '0' && getNotifications(state).some(item => item !== null && compareId(item.get('id'), state.getIn(['notifications', 'readMarkerId'])) > 0),
+  lastReadId: state.getIn(['settings', 'notifications', 'showUnread']) ? state.getIn(['notifications', 'readMarkerId']) : '0',
+  canMarkAsRead: state.getIn(['settings', 'notifications', 'showUnread']) && state.getIn(['notifications', 'readMarkerId']) !== '0' && getNotifications(state).some(item => item !== null && compareId(item.get('id'), state.getIn(['notifications', 'readMarkerId'])) > 0),
   needsNotificationPermission: state.getIn(['settings', 'notifications', 'alerts']).includes(true) && state.getIn(['notifications', 'browserSupport']) && state.getIn(['notifications', 'browserPermission']) === 'default' && !state.getIn(['settings', 'notifications', 'dismissPermissionBanner']),
 });
 

app/javascript/mastodon/reducers/settings.js

@@ -45,6 +45,7 @@ const initialState = ImmutableMap({
     }),
 
     dismissPermissionBanner: false,
+    showUnread: true,
 
     shows: ImmutableMap({
       follow: true,