import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';
import * as i0 from "@angular/core";
export declare class EtagInterceptor implements HttpInterceptor {
    /**
     * Bộ nhớ đệm lưu ETag + body cho mỗi URL GET.
     * Tự động giải phóng khi Angular app bị reload (SPA).
     */
    private cache;
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>>;
    static ɵfac: i0.ɵɵFactoryDeclaration<EtagInterceptor, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<EtagInterceptor>;
}