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