/**
 * Removes the parameters of an authorization response that cannot belong to this application.
 *
 * keycloak-js treats a URL as its own callback only when it carries `state` alongside `code` or
 * `error`, and strips the response parameters from the address bar when it does. A response
 * without `state` was never requested by this application — keycloak-js always sends one — so it
 * goes unrecognized and the parameters are left behind. They would then be sent as the
 * `redirect_uri` of the next authorization request made from the page, which the server rejects
 * for carrying OIDC response parameters, leaving the page unable to log in at all.
 *
 * @param url the current URL
 * @returns the URL with the response parameters removed, or `undefined` if it should be left as
 * it is, either because it carries no response or because the response belongs to this
 * application and keycloak-js will deal with it.
 */
export declare function stripForeignAuthResponse(url: string): string | undefined;