add try-catch, return copy ov values

projects/nshmp-apps/src/app/gmm/spectra/services/app.service.ts

@@ -287,10 +287,20 @@ export class AppService
 
     this.nshmpService
       .callServices$<GmmSpectraResponse>(urls)
-      .pipe(catchError((error: Error) => this.nshmpService.throwError$(error)))
+      .pipe(
+        catchError((error: Error) => {
+          spinnerRef.close();
+          return this.nshmpService.throwError$(error);
+        }),
+      )
       .subscribe(serviceResponses => {
-        this.handleServiceResponses(serviceResponses);
-        spinnerRef.close();
+        try {
+          this.handleServiceResponses(serviceResponses);
+          spinnerRef.close();
+        } catch (error) {
+          spinnerRef.close();
+          this.nshmpService.throwError$(error as Error);
+        }
       });
   }
 
@@ -521,7 +531,7 @@ export class AppService
       })
       .sort((a, b) => a - b);
 
-    return xValues;
+    return [...xValues];
   }
 
   private handleServiceResponses(serviceResponses: GmmSpectraResponse[]): void {