How to handle 401 (Authentication Error) in axios and react?

If you want to use interceptors to handle 401 error here is code snippet.

axios.interceptors.response.use(response => {   return response;}, error => {  if (error.response.status === 401) {   //place your reentry code  }  return error;});

I got it working with following code

import axios from 'axios';import config from '../../configuration.json';import qs from 'qs';const baseURL = config['baseUrl_local'];let authTokenRequest;/**  * @description axios instance for ajax requests*/ var client = axios.create({baseURL: baseURL,headers: {    appID: 8,    version: "1.1.0",    empID: localStorage.getItem('empID'),    token: localStorage.getItem('accessToken')}});/** * @description this method calls a requestNewToken method to issue a  new token to the client*/  function getAuthToken() {   if (!authTokenRequest) {   authTokenRequest = requestNewToken();   authTokenRequest.then(resetAuthTokenRequest, resetAuthTokenRequest); } return authTokenRequest; }/**  * @description this method requests the server to issue a new token,   the server response is updated in local storage accessToken*/ function requestNewToken() {  var newToken = request({  method: "post",  url: '/sign-in',  data:  qs.stringify({         "userName":localStorage.getItem('userName'),         "password":localStorage.getItem('password')         })    }).then((res)=>{  if(res.status == "success"){    localStorage.setItem('accessToken',res.data.accessToken);    //if featureArray is present in response object, update the     featureArray in local storage    if(res.data.features){      localStorage.setItem(      'featureArray',     JSON.stringify(res.data.features));    }    client = axios.create({     baseURL: baseURL,     headers: {          appID: 8,          version: "1.1.0",          empID: localStorage.getItem('empID'),          token: localStorage.getItem('accessToken')      }   }); } else {  window.location = "/logout"; }}); return newToken;}function resetAuthTokenRequest() {  authTokenRequest = null; }/**  * @description if any of the API gets 401 status code, this method    calls getAuthToken method to renew accessToken  * updates the error configuration and retries all failed requests   again*/ client.interceptors.response.use(undefined, err => {  const error = err.response;  // if error is 401   if (error.status===401 && error.config &&   !error.config.__isRetryRequest) {  // request for a new token  return getAuthToken().then(response => {   // update the error config with new token   error.config.__isRetryRequest = true;   error.config.headers.token= localStorage.getItem("accessToken");   return client(error.config);  }); } });/** * @description wrapper for making ajax requests * @param {object} object with method,url,data etc.*/ const request = function(options) {  const onSuccess = function(response) {    return response.data;  } const onError = function(error) {  //console.error('Request Failed:', error.config);   if (error.response) {  //console.error('Status:',  error.response.status);  //console.error('Data:',    error.response.data);  //console.error('Headers:', error.response.headers);  } else {  console.error('Error Message:', error.message);  } return Promise.reject(error.response || error.message); }return client(options)        .then(onSuccess)        .catch(onError);        options}export default request;

[EDIT] Its 2019, Here is yet another implementation for the same. The above solution is great but does not work well with multiple failed request, in turn it calls getToken with the updated token as well.

 import axios from "axios"; /* @internal */ import config from "../config"; import TokenService from "./token_service";class Request {    constructor() {        this.baseURL = config.baseUrl;        this.isRefreshing = false;        this.failedRequests = [];        this.tokenService = new TokenService();        this.client = axios.create({            baseURL: config.apiServerBaseUrl,            headers: {               clientSecret: this.clientSecret,            },        });        this.beforeRequest = this.beforeRequest.bind(this);        this.onRequestFailure = this.onRequestFailure.bind(this);        this.processQueue = this.processQueue.bind(this);        this.client.interceptors.request.use(this.beforeRequest);        this.client.interceptors.response.use(this.onRequestSuccess, this.onRequestFailure);}beforeRequest(request) {    const token = TokenService.getAccessToken();    request.headers.Authorization = `Token ${token}`;    return request;}static onRequestSuccess(response) {    return response.data;}async onRequestFailure(err) {    const { response } = err;    if (response.status === 401 && err && err.config && !err.config.__isRetryRequest) {        if (this.isRefreshing) {            try {                const token = await new Promise((resolve, reject) => {                    this.failedRequests.push({ resolve, reject });                });                err.config.headers.Authorization = `Bearer ${token}`;                return this.client(err.config);            }            catch (e) {                return e;            }        }        this.isRefreshing = true;        err.config.__isRetryRequest = true;        return new Promise((resolve, reject) => {            this.tokenService.refreshAccessToken().then((token) => {                this.tokenService.setAccessToken(token);                err.config.headers.Authorization = `Bearer ${token}`;                this.isRefreshing = false;                this.processQueue(null, token);                resolve(this.client(err.config));            }).catch((e) => {                this.processQueue(e, null);                reject(err.response);            });        });    }    throw response;}processQueue(error, token = null) {    this.failedRequests.forEach((prom) => {        if (error) {            prom.reject(error);        } else {            prom.resolve(token);        }       });        this.failedRequests = [];    }}const request = new Request();export default request.client;

This works:

// Add a 401 response interceptorwindow.axios.interceptors.response.use(function (response) {    return response;}, function (error) {    if (401 === error.response.status) {        // handle error: inform user, go to login, etc    } else {        return Promise.reject(error);    }});

Extracted from:https://gist.github.com/yajra/5f5551649b20c8f668aec48549ef5c1f

I had this extra issue:

"Network Error" without any response

tl;dr - It was a problem with CORS and how it was setup, so axios never got the information back from the browser. You have to sort it out from the server side.

Description

if you have a similar problem, you'll see it in the browser console. The browser will prevent you from accessing a different url over ajax.

In my particular case (node.js - express) was the order of the filter, the CORS filter (dev environment) was added after the handler for this particular request, so the server wasn't sending the proper CORS headers at the time and thus the browser wasn't even allowing the request to take place (there was no call to the server whatsoever, thus no error object got returned).