import type { Request } from 'express';
export declare function getNanoTimestamp(): bigint;
export declare const randomBytesAsync: (arg1: number) => Promise<NonSharedBuffer>;
export declare const isValidInteger: (num: any) => num is number;
export declare const checkInt: (num?: string) => number | false;
export declare const getIP: (req: Request) => string | undefined;
export declare const getIPv4: (req: Request) => string | undefined;
export declare const getBase64DataUri: (filePath: string, mimeType: "image/png" | "image/svg+xml") => Promise<string>;
export declare const b64decode: (str: string) => string;
export declare const throttledForEach: <T, U>(array: T[], delayMS: number, fn: (item: T) => PromiseLike<U> | U) => Promise<U[]>;
export declare const withRetries: <T>(func: () => Promise<T>, delayDuration?: number, retries?: number) => Promise<T>;
/**
 * Useful when you want to avoid having to manually parse the key
 * or when need order guarantees while iterating the keys.
 */
export declare const groupByMap: <K, V>(entries: V[], iteratee: (item: V) => K) => Map<K, V[]>;
export declare const getBodyOrQueryParam: <R extends Request, P extends (keyof R["body"] | keyof R["query"]) & string, D = undefined>(req: R, paramName: P, defaultValue?: D) => Exclude<(P extends keyof R["body"] ? R["body"][P] : never) | (P extends keyof R["query"] ? R["query"][P] : never), null> | D;