Interceptor for 401 errors

error-interceptor.ts

import { AuthService } from './../services/auth.service';

import { Injectable } from '@angular/core';

import {

  HttpRequest,

  HttpHandler,

  HttpEvent,

  HttpInterceptor,

} from '@angular/common/http';

import { Observable, throwError } from 'rxjs';

import { catchError } from 'rxjs/operators';

@Injectable()

export class ErrorInterceptor implements HttpInterceptor {

  constructor(private authenticationService: AuthService) {}

  intercept(

    request: HttpRequest<any>,

    next: HttpHandler

  ): Observable<HttpEvent<any>> {

    return next.handle(request).pipe(

      catchError((err) => {

        console.log(err);

        if (err.status === 401) {

          // auto logout if 401 response returned from api

          this.authenticationService.logout();

        }

        const error = err.error.messages || err.statusText;

        return throwError(error);

      })

    );

  }

}