async function asyncAdd(left) {
  return left + (await right);
}

function asyncAdd(left) {
    return new Promise(($return, $error) =>
      Promise.resolve(right).then($await_1 => {
        try {
            return $return(left + $await_1);
        } catch ($boundEx) {
            return $error($boundEx);
        }
      }, $error)
    );
}