Handle onMessage errors when client is not connected

Reviewed By: lblasa

Differential Revision: D47397641

fbshipit-source-id: ac9c057050a3bac0c5149f5ce2998657fededb61

desktop/flipper-frontend-core/src/AbstractClient.tsx

@@ -218,6 +218,7 @@ export default abstract class AbstractClient extends EventEmitter {
 
   // get the plugins, and update the UI
   async refreshPlugins() {
+    try {
       const oldBackgroundPlugins = this.backgroundPlugins;
       await this.loadPlugins('refresh');
       await Promise.all(
@@ -242,6 +243,13 @@ export default abstract class AbstractClient extends EventEmitter {
         }
       });
       this.emit('plugins-change');
+    } catch (e) {
+      if (this.connected) {
+        throw e;
+      } else {
+        console.warn(e);
+      }
+    }
   }
 
   onMessage(msg: string) {