all-in-one/backend/expressJS/README.md

[TOC]

# Create Express JS project

[Home](../../README.md)

[Reference](https://expressjs.com/en/starter)

Create a project skeleton

Option1 :  Using basic `npm` step 

```sh
$ mkdir myapp
$ cd myapp

$ npm init

$ npm install express --save

```



Option2 : Using `npx` express application generator. 

```sh
$ mkdir myapp
$ cd myappnpm
$ npx express-generator
$ npm install
```



Bootstrapped project folders

```sh
C:.
|   app.js
|   package-lock.json
|   package.json
|
+---bin
|       www
|
+---public
|   +---images
|   +---javascripts
|   \---stylesheets
|           style.css
|
+---routes
|       index.js
|       users.js
|
\---views
        error.jade
        index.jade
        layout.jade
```



Launch `vscode` IDE

```sh
$ code .
```



Validate the `./bin/www.js`. By default, server serve at port 3000

```javascript

var port = normalizePort(process.env.PORT || '3000');
app.set('port', port);

```



Add new route in `app.js` for *helloworld* routing

```javascript
var helloworldRouter = require('./routes/helloworld');
//...
app.use('/', indexRouter);
app.use('/users', usersRouter);
// new routing to helloworld
app.use('/helloworld', helloworldRouter);
```



Create new routing for `./routes/helloworld.js`

```javascript
var express = require('express');
var router = express.Router();

// GET method
router.get('/', function (req, res) {
    res.send('Hello World!')
  })
  
// POST method
router.post('/', function (req, res) {
    res.send('Got a POST request')
})

// PUT method
router.put('/user', function (req, res) {
    res.send('Got a PUT request at helloworld/user')
})
  
module.exports = router;
```



Run the server

```sh
$ npm start
...
> expressjs@0.0.0 start C:\dev\playground\expressJS
> node ./bin/www
```



Browse [localhost](http://localhost:3000). You should see the text in browser

```text
Express
Welcome to Express
```



Use *Postman* to execute 'POST', 'PUT' methods

[Postman json](./postman_collection.json)

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