example.js

const {response} = require("spirit").node

(handler) => {
  return async (request) => {

    const userExists = await calltoDB(request.user)
    if (!userExists) return response("you have to login!")

    return handler(request)
  }
}

// manual way, mostly equivalent to the above without using response()
(handler) => {
  return async (request) => {

    const userExists = await calltoDB(request.user)
    if (!userExists) return { status: 200, headers: {}, body: "you have to login!" }

    return handler(request)
  }
}