interceptors.ts

@Injectable()
export class I1 implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        const modified = req.clone({setHeaders: {'Custom-Header-1': '1'}});
        return next.handle(modified);
    }
}

@Injectable()
export class I2 implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        const modified = req.clone({setHeaders: {'Custom-Header-2': '2'}});
        return next.handle(modified);
    }
}