freeCodeCamp/server/utils/middleware.js

export function ifNoUserRedirectTo(url, message, type = 'errors') {
  return function(req, res, next) {
    const { path } = req;
    if (req.user) {
      return next();
    }

    req.flash(type, {
      msg: message || `You must be signed in to access ${path}`
    });

    return res.redirect(url);
  };
}

export function ifNoUserSend(sendThis) {
  return function(req, res, next) {
    if (req.user) {
      return next();
    }
    return res.status(200).send(sendThis);
  };
}

export function ifNoUser401(req, res, next) {
  if (req.user) {
    return next();
  }
  return res.status(401).end();
}