Node.js is a JavaScript runtime built on Chrome's JavaScript engine for building fast and scalable network applications. It uses non-blocking I/O and event-driven architecture, making it suitable for real-time applications with many simultaneous connections. The document provides an example of an HTTP server in Node.js and discusses key aspects of the platform like the event loop, modules, and package management with npm. It also introduces Express.js as a popular web framework built on Node.js that simplifies building web servers.

1. NodeJS, CS y ExpressJS
Como programar solo en JavaScript
y no morir en el intento.

2. “es una plataforma construida sobre el
Javascript runtime de Chrome, con el fin de
construir aplicaciones de red rápidas y
escalables.”

3. Esencialmente
I/O

4. - http
- net(tcp)
- udp
- fs
- dns
- etc...
Muchos modulos

5. HTTP Server de ejemplo
var http = require('http');
http.createServer(function (request, response) {
response.writeHead(200, {'Content-Type': 'text/plain'});
response.end('Hello Worldn');
}).listen(8124);
console.log('Server running at http://127.0.0.1:8124/');

6. - single threaded
- todo I/O es no bloqueante
- muchos callbacks
- no bloquear el reactor
Event Loop

7. Require()
//mate.js
var mate = {
cuadrado: function(x) {
return x * x
},
cubo: function(x) {
return x * cuadrado(x);
}
};
module.exports = math;
//otro.js
var express = require('express')
var mate = require('./mate.js')
mate.cuadrado(2);
mate.cubo(2);

8. - Instalar modulos:
Node Package Manager
npm install express
- Manejar dependencias (definidas en package.json):
npm install
gem install sinatra
bundle install
- Congelar dependencias:
npm shrinkwrap Gemfile.lock

9. package.json
{
"name": "TicTacToeNODE",
"version": "1.0.0",
"description": "",
"main": "app.js",
"engines": {
"node": "~1.4.28"
},
"dependencies": {
"body-parser": "^1.10.1",
"express": "^4.10.7",
"express-session": "^1.10.0",
"mongodb": "^1.4.28"
},
"devDependencies": {
"coffee-script": "^1.8.0"
},
"author": "",
"license": "ISC"
}

10. Dato Curioso
rubyGems: 94,343 gems (desde 2003).
npm: 116,873 packages (desde 20011).

11. - lenguaje que compila a javascript.
- es directamente compatible con librerías.
javascript (y vice-versa).
- sintaxis bonita. :D
- tiene su propia consola para node.

12. numero = 15
numeros = [1, 2, 3]
nombres = [
'Santi'
'Miguel'
'Mati'
]
cuadrado = (x) ->
x * x
mate =
cuadrado: (x) ->
x * x
cubo: (x) ->
x * cuadrado x
if numero > 10
console.log "Un numero: #{numero}"
console.log("Un numero: #{numero}") if numero > 10
var numero = 15;
var numeros = [1, 2, 3];
var nombres = ['Santi',
'Miguel',
'Mati'];
var cuadrado = function(x) {
return x * x
};
var mate = {
cuadrado: function(x) {
return x * x
},
cubo: function(x) {
return x * cuadrado(x);
}
};
if (numero > 10) {
console.log("Un numero: " + numero);
};
Javascript Coffeescript

13. Clases
class WinConditionRow
constructor: (rowNumber) ->
@rowNumber = rowNumber
hasWon: (board, player) ->
board[@rowNumber].every (cell) ->
cell == player
winCondition = new WinConditionRow(1)
winCondition.hasWon(board, player)
class Persona
constructor: (nombre, apellido) ->
@nombre = nombre
@apellido = apellido
obtenerNombreCompleto: ->
"#{@nombre} #{@apellido}"
class Doctor extends Persona
obtenerNombreCompleto: ->
"Dr. #{super()}"

14. Listas y bucles
num for num in [1..10]
game.getId() for game in games when game.isFinished()
for game in games
do (game) ->
game.play player, 0, 0
console.log game.getBoard()

15. ExpressJS
- framework web similar a Sinatra.
- super minimalista y modular.
express = require 'express'
app = express()
app.get '/', (req, res) ->
res.send 'Hello World!'
app.listen 3000

16. get '/match_ups' do
currentPlayerId = session[:player_id]
{player_id: currentPlayerId,
match_ups_pending_id: getPendingMatchUpsFor(currentPlayerId),
match_ups_finished_id: getFinishedMatchUpsFor(currentPlayerId)
}.to_json
end
app.get '/match_ups', (req, res) ->
currentPlayerId = req.session.playerId
resJSON =
player_id: currentPlayerId
match_ups_pending_id: pendingMatchUpIdsBy currentPlayerId
match_ups_finished_id: finishedMatchUpIdsBy currentPlayerId
res.send resJSON
express
Sinatra

17. session = require 'express-session'
bodyParser = require 'body-parser'
app.use express.static("#{__dirname}/public")
app.use bodyParser.json()
app.use session(cookieConfig)
app.post '/play_match_up/:match_up_id', (req, res) ->
gameId = parseInt req.params.match_up_id
i = parseInt req.body.i
j = parseInt req.body.j
game = getGameById(gameId)
game.play req.session.playerId, i, j
res.sendStatus 200

18. Conclusiones