authenticator.js

function login (socket, access_token, cb) {
  Token.get(access_token).nodeify(function (err, token) {
    if (err)
      return cb(err)

    if (!token)
      return cb(Error.Unauthorized('Invalid credentials'))

    if (token.expire_date) {
      const expirey = new Date(token.expire_date)

      if (expirey < (new Date()).getTime()) {
        return cb(Error.Unauthorized('Token expired'))
      }
    }

    if (token.type !== 'access')
      return cb(Error.Unauthorized('Invalid credentials'))

    User.get(token.user_id, function (err, user) {
      if (err)
        return cb(err)

      if (!user)
        return cb(Error.ResourceNotFound('Unknown user'))

      process.domain.user = user
      socket.user = user
      socket.client_id = token.client_id

      joinRooms(socket, cb)
    })
  })
}

nodeifier.js

const nodeify = promise => {
  let callback

  const resolve = res => {
    callback(null, res)
  }

  const reject = err => {
    callback(err)
  }

  promise
  .then(resolve)
  .catch(reject)

  return cb => {
    callback = cb
  }
}

Promise.prototype.nodeify = function(cb) {
  return nodeify(this)(cb)
}

Token.js

Token.get = async token => {
  const res = await db.query.promise('token/get', [token])

  if (res.rows.length < 1)
    throw Error.ResourceNotFound(`Token ${token} not found`)

  return res.rows[0]
}