Function wrap

packages/socket.io-client/test/support/util.ts:13–27

(fn: (done: (err?: Error) => void) => void)

 * @param fn
 */
export function wrap(fn: (done: (err?: Error) => void) => void) {
  let once = true;
  return new Promise<void>((resolve, reject) => {
    fn((err) => {
      if (!once) {
        throw "done() was called multiple times";
      } else if (err) {
        reject(err);
      } else {
        once = false;
        resolve();
      }
    });
  });
}

export function success(done, socket) {
  socket.disconnect();