Caching - Passing Context to HTTP Interceptors

cache-interceptor.ts

const CACHE_IT = new HttpContextToken<boolean>(() => false);

export function cacheIt() {
  return new HttpContext().set(CACHE_IT, true);
}

@Injectable()
export class CacheInterceptor implements HttpInterceptor {

  intercept(request: HttpRequest, next: HttpHandler): Observable<HttpEvent> {
    
    if(request.context.get(CACHE_IT)) {
       return;
    }
       
    return next.handle(request);
  }
}

users-service-cache.ts

import { cacheIt } from './cache.interceptor';

@Injectable()
export class UsersService {
  constructor(private http: HttpClient) {}
  
  getUsers() {
    return this.http.get('....', {
      context: cacheIt()
    })
  }
}