fix: backward compatibility with the plotter app

Signed-off-by: Akos Kitta <[email protected]>

Author: Akos Kitta

arduino-ide-extension/src/node/monitor-service.ts

@@ -739,6 +739,17 @@ export class MonitorService extends CoreClientAware implements Disposable {
         settings.monitorUISettings.connectionStatus
       );
     }
+    if (
+      typeof settings.monitorUISettings?.connected === 'boolean' &&
+      !('connectionStatus' in settings.monitorUISettings)
+    ) {
+      // Set the connectionStatus if the message was sent by the plotter which does not handle the new protocol. Assuming that the plotter can send anything.
+      // https://github.com/arduino/arduino-serial-plotter-webapp#monitor-settings
+      settings.monitorUISettings.connectionStatus = settings.monitorUISettings
+        .connected
+        ? 'connected'
+        : 'not-connected';
+    }
     const command: Monitor.Message = {
       command: Monitor.MiddlewareCommand.ON_SETTINGS_DID_CHANGE,
       data: settings,