Load Dynamic Routes Recursively in ExpressJS App

book.js

// A file in `routes/` folder
module.exports = (function(app, router){
  
  router
    .route('/books')
    .get((req, res, next)=>{
      if(err){
        next(err);
        // send it to error handler
      }
      else{
        res.json({"books": ["book1", "book2", "bookn"]});
      }
    });
  
  router
    .route('book/:id')
    .get((req, res, next) => { /* Custom Functionality for getting specific book */})
    .put((req, res, next) => { /* Custom Functionality for updateing specific book record in DB */});
  
})(app, router);

server.js

// routes     
processRoutePath(__dirname + "/routes");

function processRoutePath(route_path) {
    fs.readdirSync(route_path).forEach(function(file) {
        var filepath = route_path + '/' + file;
        fs.stat(filepath, function(err,stat) {
            if (stat.isDirectory()) {
                processRoutePath(filepath);
            } else {
                let router = express.Router();
                console.info('Loading route: ' + filepath);
                require(filepath)(app, router);
                app.use("/" + filepath, router);
            }
        });
    });
}