/**
 * Detect whether a whole string matches a Texas State Net ID
 */
export declare function isNetID(netid: string): boolean;
/**
 * If an input could be either a NetID or a federated NetID (e.g.
 * abc123@txstate.edu), this function will return the bare NetID
 * (e.g. abc123)
 *
 * If it does not look like either one, returns undefined
 */
export declare function extractNetIDFromFederated(login: string | undefined | null): string | undefined;
export declare function federatedFromNetID(netid: string): string;
/**
 * Detect whether a string is a valid email address on the
 * txstate.edu domain
 */
export declare function isTxStEmail<T extends string | undefined | null>(email: T): email is Exclude<T, undefined | null>;