If you are building a web application using Angular 4 or Angular 5 there’s a good chance that you might be working with JWT tokens. Luckily, implementing token interceptor and retry in Angular 4 and beyond is very easy thanks to the new HTTP Interceptors. Using this, we can add an authorization header to every outbound request while also implementing a retry mechanism for requests that fail due to an expired token. Let’s walk through the code.
App Module
The first thing that you need to do is implement the interceptors in the App module.