angular retrive headers form error code example

Example: angular http error handling

// src/app/services/interceptor.service.ts
    import { Injectable } from '@angular/core';
    import {
    HttpInterceptor, HttpRequest,
    HttpHandler, HttpEvent, HttpErrorResponse
    } from '@angular/common/http';
    import { Observable, throwError } from 'rxjs';
    import { catchError } from 'rxjs/operators';
    @Injectable({
    providedIn: 'root'
    })
    export class InterceptorService implements HttpInterceptor{
     constructor() { }
     handleError(error: HttpErrorResponse){
      console.log("lalalalalalalala");
      return throwError(error);
     }
    intercept(req: HttpRequest<any>, next: HttpHandler):
    Observable<HttpEvent<any>>{
     return next.handle(req)
     .pipe(
      catchError(this.handleError)
     )
     };
    }