/**
 * A Plaid link token is scoped to exactly one country at mint time, and the
 * OAuth leg of Plaid Link requires the *same* token the session started with.
 * So the token has to be cached, which makes it easy to hand a session a token
 * minted for the wrong rail — a US-scoped token opens the US institution list
 * no matter which country the caller asked for.
 *
 * Caching the country alongside the token lets a reader refuse a token that was
 * not minted for the rail it needs.
 */
export interface CachedLinkToken {
    token: string;
    /** Absent for flows that do not choose a rail, and for legacy cache entries. */
    country?: string;
}
export declare function serializeCachedLinkToken(cached: CachedLinkToken): string;
/**
 * Reads a cache entry, tolerating the bare-token strings written before the
 * country was recorded. Those have unknown provenance, so they come back with
 * no country and `canReuseLinkToken` will refuse them for a specific rail.
 */
export declare function parseCachedLinkToken(raw: string | null | undefined): CachedLinkToken | null;
/**
 * True when a cached token may be handed to a session for `country`.
 *
 * A caller that names a country needs a token minted for that same country;
 * anything else (a different rail, or an entry whose rail we never recorded)
 * has to be re-minted. A caller that names no country takes what is cached,
 * which is what the OAuth leg does when resuming a session already in flight.
 */
export declare function canReuseLinkToken({ cached, country, }: {
    cached: CachedLinkToken | null;
    country?: string;
}): boolean;