/**
 * Generate cryptographically-secure string id.
 * Powered by `nanoid`.
 */
export declare function stringId(length?: number, alphabet?: string): string;
/**
 * Generate a string id of Base62 alphabet (same as "alphanumeric": A-Za-z0-9)
 *
 * Length is 16 (non-configurable currently).
 */
export declare const stringIdBase62: () => string;
/**
 * Generate a string id of Base64 alphabet: A-Za-z0-9+/
 *
 * Default length is 16.
 * Length should be dividable by 4 (otherwise unexpected length will be produced).
 *
 * Dividable by 4 lengths produce ids with no padding `=` characters, which is optimal.
 */
export declare function stringIdBase64(size?: number): string;
/**
 * Generate a string id of Base64url alphabet: A-Za-z0-9-_
 *
 * Default length is 16.
 * Length should be dividable by 4 (otherwise unexpected length will be produced).
 *
 * Base64url always produces strings without a padding character `=`, by design.
 */
export declare function stringIdBase64Url(size?: number): string;