lib/router/index.js
function sendOptionsResponse(res, options, next) {
  try {
    var body = options.join(',');
    res.set('Allow', body);
    res.send(body);
  } catch (err) {
    next(err);
  }
}
function sendOptionsResponse(res, options, next) {
  try {
    var body = options.join(',');
    res.set('Allow', body);
    res.send(body);
  } catch (err) {
    next(err);
  }
}
function sendOptionsResponse ( res , options , next ) { try { var body = options . join ( ',' ) ; res . set ( 'Allow' , body ) ; res . send ( body ) ; } catch ( err ) { next ( err ) ; } }
send an OPTIONS response
send an OPTIONS response