Question

What’s the best way to handle JWT token expiration in Angular applications?

I'm building an Angular application and need to handle JWT token expiration. What’s the best way to detect and refresh expired tokens?

Answer 1

To handle JWT token expiration in Angular applications effectively, you can implement an interceptor that automatically refreshes tokens when they expire. Here’s an overview of the approach:

Create an HTTP Interceptor:

Intercept all HTTP requests and responses.

Check if the response status is 401 Unauthorized.

If so, invoke a token refresh function.

Token Refresh Logic:

Use a flag (isRefreshing) to prevent multiple concurrent refresh attempts.

Manage requests with an RxJS Subject to queue and retry them once the token is refreshed.

Error Handling:

If the refresh token itself is invalid (e.g., 403 Forbidden), log the user out and redirect them to the login page.

Asynchronous Handling:

Use RxJS operators like switchMap, catchError, and filter to synchronize the token refresh process with queued requests.