angular-interceptors

What problem does it solve?

Intercepts and modifies Angular HttpClient requests and responses to centralize concerns like authentication, header injection, response transformation, caching flags, logging, and unified error handling so individual services remain thin and consistent.

Core Features & Use Cases

• Functional Interceptors: Use HttpInterceptorFn to implement auth token attachment, header normalization, or request transformation without class boilerplate.
• Registration and Composition: Register ordered interceptors via provideHttpClient with withInterceptors to ensure predictable processing order for logging, auth, and error handling.
• Per-request Flags: Use HttpContext and HttpContextToken to enable caching or special handling on a per-request basis.
• Error Handling and Navigation: Catch HttpErrorResponse in interceptors to trigger centralized retry, logout, or route navigation workflows.
• Use Case: Attach a Bearer token to outgoing API calls, log request/response timings, and route to login on 401 responses while preserving a cache bypass flag per request.

Quick Start

Implement a functional auth interceptor that injects the current user's Bearer token, handle 401 errors by navigating to /login, and register it with provideHttpClient using withInterceptors.