///
import * as querystring from 'querystring';
export declare function normalize(optionsOrCallback?: T | U, cb?: U): {
options: T;
callback: U;
};
/**
* Flatten an object into an Array of arrays, [[key, value], ..].
* Implements Object.entries() for Node.js <8
* @internal
*/
export declare function objectEntries(obj: {
[key: string]: T;
}): Array<[string, T]>;
/**
* Encode `str` with encodeURIComponent, plus these
* reserved characters: `! * ' ( )`.
*
* @see [MDN: fixedEncodeURIComponent]{@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent}
*
* @param {string} str The URI component to encode.
* @return {string} The encoded string.
*/
export declare function fixedEncodeURIComponent(str: string): string;
/**
* URI encode `uri` for generating signed URLs, using fixedEncodeURIComponent.
*
* Encode every byte except `A-Z a-Z 0-9 ~ - . _`.
*
* @param {string} uri The URI to encode.
* @param [boolean=false] encodeSlash If `true`, the "/" character is not encoded.
* @return {string} The encoded string.
*/
export declare function encodeURI(uri: string, encodeSlash: boolean): string;
/**
* Serialize an object to a URL query string using util.encodeURI(uri, true).
* @param {string} url The object to serialize.
* @return {string} Serialized string.
*/
export declare function qsStringify(qs: querystring.ParsedUrlQueryInput): string;
export declare function objectKeyToLowercase(object: {
[key: string]: T;
}): {
[key: string]: T;
};
/**
* JSON encode str, with unicode \u+ representation.
* @param {object} obj The object to encode.
* @return {string} Serialized string.
*/
export declare function unicodeJSONStringify(obj: object): string;