/**
 * The utilities in this file are based on the NPM module `istextorbinary`.
 *
 * The implementation is copied here to reduce dependency overhead
 * and improve compatibility with NodeJS compilers like `@vercel/ncc`.
 *
 * @see the `LICENSE` file at the root of this source tree:
 *   https://github.com/bevry/istextorbinary/blob/master/source/index.ts
 */
/// <reference types="node" />
/**
 * Determine if the filename and/or buffer is binary.
 *
 * Determined by extension checks first (if filename is available), otherwise if
 * the extension is unrecognized or no filename is provided, will perform a
 * slower buffer encoding detection.
 *
 * Extension checks are quicker.
 * Encoding checks cannot guarantee accuracy for chars between utf8 and utf16.
 *
 * The extension checks are performed using the following resources:
 *   - https://github.com/bevry/textextensions
 *   - https://github.com/bevry/binaryextensions
 *
 * @param filename The filename for the file/buffer if available
 * @param buffer The buffer for the file if available
 * @returns Will be `null` if neither `filename` nor `buffer` were provided. Otherwise will be a `boolean` value with the detection result.
 */
export declare function isBinary(filename?: string | null, buffer?: Buffer | null): boolean | null;