Feat: converting || to ?? to preserve valid falsy values instead of unintentionally overriding

Author: RahwaZeslusHaile

custom-middlewares/middleware/extractUsername.js

@@ -1,6 +1,6 @@
 function extractUsername(req, res, next) {
   const username = req.get("X-Username");
-  req.username = username || null;
+  req.username = username ?? null;
   next();
 }
 module.exports = extractUsername;