Configure axios to refresh access token

If you are working with an API which uses OAuth for authentication then you need to some way of refreshing your access token when it is expired to make sure a uninterrupted user experience. And for front-end application it is very important. Axios is a promise based HTTP client which comes with a lot of great feature. Interceptors is one of the great feature we are going to talk about. It gives you the ability to intercept requests or responses before they are handled by then or catch block. That means you can easily modify it before they reach their destination.

In your react app create a config file named axiosConfig.js and add these codes below.

You can go through the documentation for further enquiry about interceptors.

import axios from 'axios'

const instance = axios.create({
	baseURL: `${process.env.REACT_APP_API_URL}`
});

instance.interceptors.request.use(
	async config => {
    	// get your token from your local storage or cookie
		const token = getToken();
		if (token) {
        	// you can set your content-type or other parameter here
			config.headers['Authorization'] = 'Bearer ' + token;
		}
		return config;
	},
	error => {
		Promise.reject(error)
	});

instance.interceptors.response.use((response) => {
    // Any status code that lie within the range of 2xx cause this function to trigger
	return response
},
	async function (error) {
		var originalRequest = error.config;

		if (error.response.status === 401 && !originalRequest._retry) {

			originalRequest._retry = true;

			const refreshToken = getRefreshToken()

			/**if only refresh token is removed somehow from your local storage
			 * remove auth token and return original request
			 * otherwise it will try to authenticate with the invalid authToken
			 * and will get invalid response each time which will be a fail attempt to login
			 * */
			if (refreshToken === undefined) {
				removeToken()
				return instance(originalRequest);
			}

			return instance.post(`/token/refresh`, { refreshToken })
				.then(response => {

					setToken({ authToken: response.data.token, refreshToken: response.data.refreshToken })

					const newAuthToken = getToken();

					instance.defaults.headers.common['Authorization'] = 'Bearer ' + newAuthToken;

					originalRequest.headers['Authorization'] = 'Bearer ' + newAuthToken;

					return instance(originalRequest);

				}).catch(error => {
					removeToken()
					redirectTo("/login")
                    return Promise.reject(error);
				})
		}
		return Promise.reject(error);
	});

export default instance;

You can even further modify the code to your needs. If you need to add some additional headers or retry a request for other statuses you can do that.