-import { Injectable, Injector } from '@angular/core';
-import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest, HttpResponse } from '@angular/common/http';
-import { Observable, of } from 'rxjs';
+import { Injectable } from '@angular/core';
+import { HttpErrorResponse, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
+import { Observable } from 'rxjs';
+import { catchError } from 'rxjs/operators';
+import { throwError } from 'rxjs';
+import { NotificationService } from './services/ui/notification.service';