How to include route handlers in multiple files in Express? [duplicate]

Question

If you want to put the routes in a separate file, for example routes.js, you can create the routes.js file in this way:

module.exports = function(app){

    app.get('/login', function(req, res){
        res.render('login', {
            title: 'Express Login'
        });
    });

    //other routes..
}

And then you can require it from app.js passing the app object in this way:

require('./routes')(app);

Have a look at these examples: https://github.com/visionmedia/express/tree/master/examples/route-separation

In Express 4.x you can get an instance of the router object and import another file that contains more routes. You can even do this recursively so your routes import other routes allowing you to create easy-to-maintain URL paths.

For example, if I have a separate route file for my /tests endpoint already and want to add a new set of routes for /tests/automated I may want to break these /automated routes out into a another file to keep my /test file small and easy to manage. It also lets you logically group routes together by URL path which can be really convenient.

Contents of ./app.js:

var express = require('express'),
    app = express();

var testRoutes = require('./routes/tests');

// Import my test routes into the path '/test'
app.use('/tests', testRoutes);

Contents of ./routes/tests.js:

var express = require('express'),
    router = express.Router();

var automatedRoutes = require('./testRoutes/automated');

router
  // Add a binding to handle '/tests'
  .get('/', function(){
    // render the /tests view
  })

  // Import my automated routes into the path '/tests/automated'
  // This works because we're already within the '/tests' route 
  // so we're simply appending more routes to the '/tests' endpoint
  .use('/automated', automatedRoutes);
 
module.exports = router;

Contents of ./routes/testRoutes/automated.js:

var express = require('express'),
    router = express.Router();

router
   // Add a binding for '/tests/automated/'
  .get('/', function(){
    // render the /tests/automated view
  })

module.exports = router;

Building on @ShadowCloud 's example I was able to dynamically include all routes in a sub directory.

routes/index.js

var fs = require('fs');

module.exports = function(app){
    fs.readdirSync(__dirname).forEach(function(file) {
        if (file == "index.js") return;
        var name = file.substr(0, file.indexOf('.'));
        require('./' + name)(app);
    });
}

Then placing route files in the routes directory like so:

routes/test1.js

module.exports = function(app){

    app.get('/test1/', function(req, res){
        //...
    });

    //other routes..
}

Repeating that for as many times as I needed and then finally in app.js placing

require('./routes')(app);

And build yet more on the previous answer, this version of routes/index.js will ignore any files not ending in .js (and itself)

var fs = require('fs');

module.exports = function(app) {
    fs.readdirSync(__dirname).forEach(function(file) {
        if (file === "index.js" || file.substr(file.lastIndexOf('.') + 1) !== 'js')
            return;
        var name = file.substr(0, file.indexOf('.'));
        require('./' + name)(app);
    });
}

Full recursive routing of all .js files inside /routes folder, put this in app.js.

// Initialize ALL routes including subfolders
var fs = require('fs');
var path = require('path');

function recursiveRoutes(folderName) {
    fs.readdirSync(folderName).forEach(function(file) {

        var fullName = path.join(folderName, file);
        var stat = fs.lstatSync(fullName);

        if (stat.isDirectory()) {
            recursiveRoutes(fullName);
        } else if (file.toLowerCase().indexOf('.js')) {
            require('./' + fullName)(app);
            console.log("require('" + fullName + "')");
        }
    });
}
recursiveRoutes('routes'); // Initialize it

in /routes you put whatevername.js and initialize your routes like this:

module.exports = function(app) {
    app.get('/', function(req, res) {
        res.render('index', { title: 'index' });
    });

    app.get('/contactus', function(req, res) {
        res.render('contactus', { title: 'contactus' });
    });
}

If you're using express-4.x with TypeScript and ES6, this would be the best template to use:

src/api/login.ts

import express, { Router, Request, Response } from "express";

const router: Router = express.Router();
// POST /user/signin
router.post('/signin', async (req: Request, res: Response) => {
    try {
        res.send('OK');
    } catch (e) {
        res.status(500).send(e.toString());
    }
});

export default router;

src/app.ts

import express, { Request, Response } from "express";
import compression from "compression";  // compresses requests
import expressValidator from "express-validator";
import bodyParser from "body-parser";
import login from './api/login';

const app = express();

app.use(compression());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(expressValidator());

app.get('/public/hc', (req: Request, res: Response) => {
  res.send('OK');
});

app.use('/user', login);

app.listen(8080, () => {
    console.log("Press CTRL-C to stop\n");
});

Much cleaner than using var and module.exports.

I am trying to update this answer with "express": "^4.16.3". This answer is similar to the one from ShortRound1911.

server.js:

const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
const db = require('./src/config/db');
const routes = require('./src/routes');
const port = 3001;

const app = new express();

//...use body-parser
app.use(bodyParser.urlencoded({ extended: true }));

//...fire connection
mongoose.connect(db.url, (err, database) => {
  if (err) return console.log(err);

  //...fire the routes
  app.use('/', routes);

  app.listen(port, () => {
    console.log('we are live on ' + port);
  });
});

/src/routes/index.js:

const express = require('express');
const app = express();

const siswaRoute = require('./siswa_route');

app.get('/', (req, res) => {
  res.json({item: 'Welcome ini separated page...'});
})
.use('/siswa', siswaRoute);

module.exports = app;

/src/routes/siswa_route.js:

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.json({item: 'Siswa page...'});
});

module.exports = app;