Function ftruncate

lib/fs.js:1321–1336

* Truncates the file descriptor. * @param {number} fd * @param {number} [len] * @param {(err?: Error) => any} callback * @returns {void}

(fd, len = 0, callback)

 * @returns {void}
 */
function ftruncate(fd, len = 0, callback) {
  if (typeof len === 'function') {
    callback = len;
    len = 0;
  }
  validateInteger(len, 'len');
  len = MathMax(0, len);
  callback = makeCallback(callback);

  const h = vfsState.handlers;
  if (h !== null && vfsVoid(h.ftruncate(fd, len), callback)) return;

  const req = new FSReqCallback();
  req.oncomplete = callback;
  binding.ftruncate(fd, len, req);
}

/**
 * Synchronously truncates the file descriptor.