Middleware for redirecting based on locale

middleware.js

module.exports = {
  ...
  middleware(self, options) {
    return {
      checkLanguage(req, res, next) {
        // if you are only doing this for the homepage, check that is the page being requested
        // possibly using req.originalUrl or the url property
        // https://v3.docs.apostrophecms.org/reference/module-api/module-overview.html#middleware-self
        // make sure 
        // if not a page you need to redirect just return next()
        let redirectLanguage = '';
        
        // get the browser languages
        const language = req.headers['accept-language'];
        // the browser languages are a word salad of country codes and 
        // preference indications
        // parse out the preferred language, but you might want to use the `locale` package
        // and (I think) locale.default
        const preferredLanguage = <the value you parsed out>;
        // store the value you got back
        if (sessionStorage.getItem('preferredLanguage') === null) {
          sessionStorage.setItem('preferredLanguage', preferredLanguage);
          redirectLanguage = preferredLanguage;
        } else {
          redirectLanguage = sessionStorage.getItem('preferredLanguage');
        }
        // add logic to figure out what page needs to be delivered set to correctUrl
        // then test to see if a redirect is needed and set notCorrectPage to true
        if (notCorrectPage) {
          // you might want to think about an alert asking the person if they want a redirect
          // instead of just redirecting
          return res.send(correctUrl);
        }
        return next();
      }
    };
  },
    ...
};