Always separate app and server files !

This is considered one of the best-practices of working with node/express
Most of us we just combine them in one single file declaration like follows

const express = require('express');

const app = express();
app.use(express.json());
// parse requests of content-type - application/json
app.use(express.json());
// parse requests of content-type - application/x-www-form-urlencoded
app.use(express.urlencoded({ extended: true }));
const httpServer = require('http').createServer(app);

httpServer.listen(PORT, () => {
  console.log(`listening on *:${process.env.PORT}`);
});

Well that's not the best we can do

Otherwise: Your API will be accessible for testing via HTTP calls only (slower and much harder to generate coverage reports). It probably won't be a big pleasure to maintain hundreds of lines of code in a single file.

So what's the alternative?

The api declaration and the the network related configuration should be separated to gain us :

testing the API in-process without having to perform the network calls
Faster testing execution
Getting wider coverage metrics of the code
Allows deploying the same API under flexible and different network conditions
Better separation of concerns and cleaner code

How to do it ?

API declaration should reside in app.js:

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);

Server network declaration, should reside in /bin/www
const app = require('../app');
const http = require('http');


// Get port from environment and store in Express.
const port = normalizePort(process.env.PORT || '3000');
app.set('port', port);

// Create HTTP server.
const server = http.createServer(app);

And the global project structure should be like follows

I hope this was helpful to develop more good habits and best practices !

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Always separate app and server files !

nermineslimane

Well that's not the best we can do

So what's the alternative?

How to do it ?

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