====== Express JS ======

====== Basic ======

==== Installing ====
  - Create a packages.json: ''$ npm init''
  - Install Express and save it in packages: ''$ npm install express --save''

==== Basic app ====
<code>
var express = require('express');

var app = express();

app.listen(3000, function() {
  console.log("server started on Port 3000");
})
</code>

=== Routes ===
Take the get to de home (using request and the response):
<code>
app.get('/', fucntion(req, res) {
  res.send('Hello world');
});
</code>
<code>
app.post('/users/add', function(req, res){
  console.log(req.body.firstName);
  res.redirect('/');
});
</code>
<code>
app.delete('/users/:id', function(req, res) {
  console.log(req.params.id);
});
</code>

=== Things to do with the response ===
Return a variable in its json format: ''res.json(person);''

==== Special functions ====
''use'' is important to put it before any request.
<code>
var logger = function (req, res, next){
  console.log('Logging');
  next();
}
app.use(logger);
</code>

Set the view engine
<code>
app.set('view engine', 'ejs');
// with this we can render views:
res.render('index');
</code>

Set the views folder:
<code>
app.set('views', path.join(__dirname, 'views');
</code>

Set global variables
<code>
app.use(function(req, res, next) {
  res.locals.errors = null;
  next();
});
</code>

=== Static path ===
Add a "public" path:
<code>
var path = require('path');
app.use(express.static(path.join(__dirname, 'public'));
</code>

===== Notes =====

==== Modular applications ====

I generally use 1 file per route and put all my routing files in a routes folder and leverage the Router available in express.

A route file could look like this:
<code>
var express = require('express');
var router = express.Router();
router.get('/', function (req, res) {
    res.send('Hello World!');
});

module.exports = router;
</code>
Then in the app file, simply add:
<code>
var example = require('./routes/example');
app.use('/', example);
</code>
The routes in the routing file are relative to the route you declare in app.use.