client/src/utils/language.js

   1 // TODO: adapt for client side https://stackoverflow.com/a/4079798
   2 // ==> Each translation file should be loaded dynamically
   3 // (each rules definition too, + modal welcome)
   4
   5 // Select a language based on browser preferences, or cookie
   6 module.exports = function(req, res)
   7 {
   8     // If preferred language already set:
   9     if (!!req.cookies["lang"])
  10         return req.cookies["lang"];
  11
  12     // Else: search and set it
  13     const supportedLang = ["en","es","fr"];
  14     const langString = req.headers["accept-language"];
  15     let langArray = langString
  16         .replace(/;q=[0-9.]+/g, "") //priority
  17         .replace(/-[A-Z]+/g, "") //region (skipped for now...)
  18         .split(",") //may have some duplicates, but removal is too costly
  19     let bestLang = "en"; //default: English
  20     for (let lang of langArray)
  21     {
  22         if (supportedLang.includes(lang))
  23         {
  24             bestLang = lang;
  25             break;
  26         }
  27     }
  28     // Cookie expires in 183 days (expressed in milliseconds)
  29     res.cookie('lang', bestLang, { maxAge: 183*24*3600*1000 });
  30     return bestLang;
  31 }