What is the convention of separating APIs as modules in NodeJS? - node.js

Question

Here is how my app.js looks like...
I want to know how do I separate this single file into multiple files for better code quality. How do we do that?
My idea is to have the below files...
server.js -> for server related properties
serve.js -> this becomes the main file in the package.json
apis -> this shall be the file with apis, I shd be able to separate apis depending upon the modules too...
What is the preferred convention in NodeJS? I am sure that we do not want to write all apis in one single file.
const express = require('express') // import express module
const app = express() // initiate express app
app.use(express.json()) // not sure what this is but without it POST cant read the JSON parameters from the body
const host = 'localhost' // host
const port = process.env.PORT || 1338 // pick port
const routePrefix = '/' + 'api' + '/' // this is the route prefix used from where the APIs will be accesssed
const routes = { // define routes
root: routePrefix + 'root',
test: routePrefix + 'test',
items: routePrefix + 'items',
item: routePrefix + 'items/:id'
}
// print details
function printDetails(currentRoute, requestMethod, requestParams,
requestQuetyString) {
console.log(currentRoute, requestMethod, requestParams, requestQuetyString);
}
// get root
app.get(routes.root, (req, res) => {
printDetails(routes.root, req.method, req.params, req.query)
res.send(routes.root)
})
// get test route
app.get(routes.test, (req, res) => {
printDetails(routes.test, req.method, req.params, req.query)
res.send(routes.test)
})
// for the web server
app.use(express.static('../public')) // this is where static files reside and need to be served to for the clientside app
// start the API server and Web server
app.listen(port, () => {
console.log(`
\nExpress Server started on port ${port}..
APIs can be accessed at http://${host}:${port}${routePrefix}
Web Server started on port http://${host}:${port}
`)
})
I have tried it on my own and the respective files look like this. However, I am unable to run this.
server.js
const express = require('express') // import express module
const app = express() // initiate express app
app.use(express.json()) // not sure what this is but without it POST cant read the JSON parameters from the body
//const api = require('./apis')
//const app = api.app
const host = 'localhost' // host
const port = process.env.PORT || 1338 // pick port
const routePrefix = '/' + 'api' + '/' // this is the route prefix used from where the APIs will be accesssed
const routes = { // define routes
root: routePrefix + 'root',
test: routePrefix + 'test',
items: routePrefix + 'items',
item: routePrefix + 'items/:id'
}
// for the web server
app.use(express.static('../public')) // this is where static files reside and need to be served to for the clientside app
module.exports = {
app: app,
host: host,
port: port,
routePrefix: routePrefix,
routes: routes
}
serve.js
const server = require('./server') // import server module
//const app = server.app
// start the API server and Web server
server.app.listen(server.port, () => {
console.log(`
\nExpress Server started on port ${server.port}..
APIs can be accessed at http://${server.host}:${server.port}${server.routePrefix}
Web Server started on port http://${server.host}:${server.port}
`)
})
api.js
'use strict'
const server = require('./server') // import sever module
const app = server.app
// get test route
app.get(server.routes.test, (req, res) => {
printDetails(server.routes.test, req.method, req.params, req.query)
res.send(server.routes.test)
})
module.exports = {
}
The problem I am facing is how do I use module.exports and what do I need to export from what module. My requirement is when I run "node serve.js", I should be able to run the APIs and they should be available for the client. How do I achieve this?

Answer 1

I think that the following structure is much more maintainable and easier to understand (also this is the more commonly used structure in new web apps in node):
├───client <-- Your web client application directory
│ └───assets
├───common <-- Common (shared) files between client and server
└───server <-- Your SugoiJS server directory
├───config <-- Build config (environment, webpack)
│ └───webpack
└───src <-- Your server app source code
├───app <-- Bootstrap module, Server initialize and listener files, 'authorization' class(optional)
│ └───classes
├───config <-- Server configuration (services, paths, etc.)
└───modules <-- All of you application modules
└───index <-- Single module
├───controllers <-- Modules' controllers
├───models <-- Modules' models(optional)
└───services <-- Modules' services
This is taken from SugoiJS framework.
https://wiki.sugoijs.com/get-started
Then basically all the routes you are writing will be controllers :)

Answer 2

There are many ways to split up JS code into files, the simplest way (that is still quite efficient) is to require modules. Here's a full guide, and here's a minimal demo:
// lib.js
module.exports = {
x: 10,
y: () => 20
}
// index.js
const lib = require('./lib');
console.log(lib.x); // 10
console.log(lib.y()); // 20
To keep the code clear, simple and efficient, requiring a module should not have any side effects (ie deleting a file, or making requests): for example, define a Class inside a module, and export it.
There are other ways to split up code between files, such as import/export.