Save flow diagram preference to localStorage

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

@@ -110,6 +110,7 @@ export class StateService {
 
   blockScrolling$: Subject<boolean> = new Subject<boolean>();
   timeLtr: BehaviorSubject<boolean>;
+  hideFlow: BehaviorSubject<boolean>;
 
   constructor(
     @Inject(PLATFORM_ID) private platformId: any,
@@ -159,6 +160,16 @@ export class StateService {
     this.timeLtr.subscribe((ltr) => {
       this.storageService.setValue('time-preference-ltr', ltr ? 'true' : 'false');
     });
+
+    const savedFlowPreference = this.storageService.getValue('flow-preference');
+    this.hideFlow = new BehaviorSubject<boolean>(savedFlowPreference === 'hide');
+    this.hideFlow.subscribe((hide) => {
+      if (hide) {
+        this.storageService.setValue('flow-preference', hide ? 'hide' : 'show');
+      } else {
+        this.storageService.removeItem('flow-preference');
+      }
+    });
   }
 
   setNetworkBasedonUrl(url: string) {

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

@@ -46,4 +46,12 @@ export class StorageService {
       console.log(e);
     }
   }
+
+  removeItem(key: string): void {
+    try {
+      localStorage.removeItem(key);
+    } catch (e) {
+      console.log(e);
+    }
+  }
 }