NgRx Effect behavior during concurrent 401 Unauthorized responses

In an Angular application using NgRx, the standard pattern for handling expired credentials involves an HTTP Interceptor that dispatches a logout action upon receiving a 401 Unauthorized response. This action is then handled by an NgRx Effect to clear the store and redirect the user.

When multiple concurrent API requests fail simultaneously due to token expiration, the interceptor may dispatch multiple identical logout actions in rapid succession. This creates uncertainty regarding the execution flow of the associated Effect, as the store state may be cleared by the first action while subsequent actions are still in the pipeline.

Constraints

• The solution must prevent redundant redirect cycles.
• The state must be cleared atomically to avoid inconsistent UI states during the logout sequence.

Which NgRx Effect operator is most effective for suppressing duplicate logout sequences caused by concurrent 401 errors? How can the state be synchronized to ensure only one authentication reset occurs regardless of the number of failing requests?