error handling with http interceptor not working in Angular code example

Example 1: interceptor error handling angular 9

import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';
export class HttpErrorInterceptor implements HttpInterceptor {
  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(request)
      .pipe(
        catchError((error: HttpErrorResponse) => {
          let errorMsg = '';
          if (error.error instanceof ErrorEvent) {
            console.log('this is client side error');
            errorMsg = `Error: ${error.error.message}`;
          }
          else {
            console.log('this is server side error');
            errorMsg = `Error Code: ${error.status},  Message: ${error.message}`;
          }
          console.log(errorMsg);
          return throwError(errorMsg);
        })
      )
  }
}

Example 2: angularjs interceptor

// register the interceptor as a service
$provide.factory('myHttpInterceptor', function($q, dependency1, dependency2) {
  return {
    // optional method
    'request': function(config) {
      // do something on success
      return config;
    },

    // optional method
   'requestError': function(rejection) {
      // do something on error
      if (canRecover(rejection)) {
        return responseOrNewPromise
      }
      return $q.reject(rejection);
    },



    // optional method
    'response': function(response) {
      // do something on success
      return response;
    },

    // optional method
   'responseError': function(rejection) {
      // do something on error
      if (canRecover(rejection)) {
        return responseOrNewPromise
      }
      return $q.reject(rejection);
    }
  };
});

$httpProvider.interceptors.push('myHttpInterceptor');


// alternatively, register the interceptor via an anonymous factory
$httpProvider.interceptors.push(function($q, dependency1, dependency2) {
  return {
   'request': function(config) {
       // same as above
    },

    'response': function(response) {
       // same as above
    }
  };
});