fix websocket connection state observable

frontend/src/app/dashboard/dashboard.component.ts

@@ -1,6 +1,6 @@
 import { AfterViewInit, ChangeDetectionStrategy, Component, OnDestroy, OnInit } from '@angular/core';
 import { combineLatest, merge, Observable, of, Subscription } from 'rxjs';
-import { filter, map, scan, share, switchMap, tap } from 'rxjs/operators';
+import { catchError, filter, map, scan, share, switchMap, tap } from 'rxjs/operators';
 import { BlockExtended, OptimizedMempoolStats } from '../interfaces/node-api.interface';
 import { MempoolInfo, TransactionStripped, ReplacementInfo } from '../interfaces/websocket.interface';
 import { ApiService } from '../services/api.service';
@@ -171,7 +171,11 @@ export class DashboardComponent implements OnInit, OnDestroy, AfterViewInit {
     this.mempoolStats$ = this.stateService.connectionState$
       .pipe(
         filter((state) => state === 2),
-        switchMap(() => this.apiService.list2HStatistics$()),
+        switchMap(() => this.apiService.list2HStatistics$().pipe(
+          catchError((e) => {
+            return of(null);
+          })
+        )),
         switchMap((mempoolStats) => {
           return merge(
             this.stateService.live2Chart$
@@ -186,10 +190,14 @@ export class DashboardComponent implements OnInit, OnDestroy, AfterViewInit {
           );
         }),
         map((mempoolStats) => {
-          return {
-            mempool: mempoolStats,
-            weightPerSecond: this.handleNewMempoolData(mempoolStats.concat([])),
-          };
+          if (mempoolStats) {
+            return {
+              mempool: mempoolStats,
+              weightPerSecond: this.handleNewMempoolData(mempoolStats.concat([])),
+            };
+          } else {
+            return null;
+          }
         }),
         share(),
       );

frontend/src/app/services/websocket.service.ts

@@ -113,7 +113,7 @@ export class WebsocketService {
           this.stateService.connectionState$.next(2);
         }
 
-        if (this.stateService.connectionState$.value === 1) {
+        if (this.stateService.connectionState$.value !== 2) {
           this.stateService.connectionState$.next(2);
         }