export = fetch;

/**
 * Node-style callback as used by {@link util.fetch}.
 * @typedef FetchCallback
 * @type {function}
 * @param {?Error} error Error, if any, otherwise `null`
 * @param {string} [contents] File contents, if there hasn't been an error
 * @returns {undefined}
 */
type FetchCallback = (error: Error, contents?: string) => void;

/**
 * Options as used by {@link util.fetch}.
 * @typedef FetchOptions
 * @type {Object}
 * @property {boolean} [binary=false] Whether expecting a binary response
 * @property {boolean} [xhr=false] If `true`, forces the use of XMLHttpRequest
 */

interface FetchOptions {
    binary?: boolean;
    xhr?: boolean
}

/**
 * Fetches the contents of a file.
 * @memberof util
 * @param {string} filename File path or url
 * @param {FetchOptions} options Fetch options
 * @param {FetchCallback} callback Callback function
 * @returns {undefined}
 */
declare function fetch(filename: string, options: FetchOptions, callback: FetchCallback): void;

/**
 * Fetches the contents of a file.
 * @name util.fetch
 * @function
 * @param {string} path File path or url
 * @param {FetchCallback} callback Callback function
 * @returns {undefined}
 * @variation 2
 */
declare function fetch(path: string, callback: FetchCallback): void;

/**
 * Fetches the contents of a file.
 * @name util.fetch
 * @function
 * @param {string} path File path or url
 * @param {FetchOptions} [options] Fetch options
 * @returns {Promise<string|Uint8Array>} Promise
 * @variation 3
 */
declare function fetch(path: string, options?: FetchOptions): Promise<(string|Uint8Array)>;