NodeJS: Lessons learned
#whoami
Join us!
Let's start?
Once upon a time...
Forgot!
Design Patterns
not only Object Oriented Programming
A lot of referencies
#NOT
Async
Design Patterns
We need be more specific sometimes
function async() {
setTimeout(function(){
console.log(' async!');
});
}
async();
console.log('Think');Async is more than this
Async is...
Proactor
Or your nickname "Promise"
var promise = new Promise(function(resolve, reject) {
resolve(3);
});
Promise.all([true, promise]).then(function(values) {
console.log(values); // # [true, 3];
});
Observers
&
Event Emitter
var events = require('events');
var eventEmitter = new events.EventEmitter();
var five = require('johnny-five');
var board = new five.Board();
var ringBell = function ringBell() {
// Creates a piezo object and defines the pin to be used for the signal
var piezo = new five.Piezo(3);
// Injects the piezo into the repl
board.repl.inject({
piezo: piezo
});
piezo.play({
// The first argument is the note (null means "no note")
song: [
// Array of arrays with song data
],
tempo: 100
});
// Plays the same song with a string representation
piezo.play({
// song is composed by a string of notes
song: "C D F D A - A A A A G G G G - - C D F D G - G G G G F F F F - -",
beats: 1 / 4,
tempo: 100
});
}
eventEmitter.on('doorOpen', ringBell);
...
eventEmitter.emit('doorOpen');Factory
function BaseClass(options) {
this.options = options;
};
function create(options) {
return new BaseClass(options);
};
module.exports = {
create: create
}; Streams
@substack likes this part
process.stdin.on('readable', function () {
var buf = process.stdin.read(3);
console.dir(buf);
});
$ (echo abc; sleep 1; echo def; sleep 1; echo ghi) | node consume.js
<Buffer 61 62 63>
<Buffer 0a 64 65>
<Buffer 66 0a 67>https://github.com/substack/stream-handbook
Would like to know more about it?
Middlewares
MIDDLE...WHAT?
var BASIC_AUTH = [
{
name: process.env.BASIC_AUTH_USERNAME,
pass: process.env.BASIC_AUTH_PASSWORD
},
{
name: process.env.BASIC_AUTH_USERNAME2,
pass: process.env.BASIC_AUTH_PASSWORD2
}
];
var callbackHandlerGet = function(req, res) {
// ... your magic code =)
}
var basicAuthMultipleCredentials = require('./basic-auth-multiple-credentials');
router.get('/multiple-credential-check',
basicAuthMultipleCredentials(BASIC_AUTH),
callbackHandlerGet); var auth = require('basic-auth');
module.exports = function(usersAndPasswords) {
if (!(usersAndPasswords instanceof Array)) {
usersAndPasswords = [usersAndPasswords];
}
return function(req, res, next) {
var credentials = auth(req);
var authenticated = function(credentials){
return usersAndPasswords.filter(function(registeredUser) {
return credentials.name === registeredUser.name &&
credentials.pass === registeredUser.pass;
}).length === 1;
};
if (!credentials || !authenticated(credentials)) {
res.statusCode = 401;
res.setHeader('WWW-Authenticate', 'Basic realm="example"');
res.end('Access denied');
} else {
next();
}
};
};Why, if this way is so simple?
Middlewares
===
Reusability
Try use small modules when you can
++ @substack likes this part
https://www.quora.com/What-are-some-best-architecture-practices-when-designing-a-nodejs-system
How
To
Learn
U.M.R.U.M. - #NKO2013
NOT BAD
Real Time
doesn't
exist
LESSONS LEARNED
Know about it
!==
use all
The micro* way
Microservices, microframeworks, micro-whatever...
Microservice +
+ Mobile App
+ Desktop App
+ WebApp
Microservice +
- Resource
- Monilithic apps
Modularizing everything
Be lazy, guy
... And don't forget this, ok? Or ...
Functional Programming
Making our life easy
Reactive Functional Programming
Making our life MUCH easier
Proactor?
Promises?
Monads
// Example in http://codepen.io/willmendesneto/pen/Iguor
$.get('http://worldcup.sfg.io/matches', function(data){
var playgame = '';
data.forEach(function(item){
if (item.status === 'completed') {
playgame = item.home_team.country +
' ' + item.home_team.goals +
' x ' + item.away_team.country +
' ' + item.away_team.goals;
console.log(playgame);
}
});
}, 'json');
$.get('http://worldcup.sfg.io/matches', function(data){
var completePlays = [],
playgame = '';
data.filter(function(item, i){
if (item.status === 'completed') {
return item;
}
}, []).sort(function(a,b){
return new Date(a.datetime) - new Date(b.datetime);
}).forEach(function(item, i){
playgame = item.location +
': ' + item.home_team.country +
' ' + item.home_team.goals +
' x ' + item.away_team.country +
' ' + item.away_team.goals;
completePlays.push(playgame);
});
console.log(completePlays.join(''));
}); function WorldCup(){
this.completePlays = [];
this.url = 'http://worldcup.sfg.io/matches';
}
var playgame = '';
WorldCup.prototype.loadData = function() {
var self = this
$.get(this.url, function(data){
data = self.filterData(data);
self.listsPlays(data);
console.log(self.completePlays.join('\n'));
});
};
WorldCup.prototype.listsPlays = function(data) {
var self = this;
data.forEach(function(item, i){
playgame = item.location +
': ' + item.home_team.country +
' ' + item.home_team.goals +
' x ' + item.away_team.country +
' ' + item.away_team.goals;
self.completePlays.push(playgame);
});
};
var WorldCup = new WorldCup();
WorldCup.loadData();Javascript everywhere
why not?
#codetime
Build checker
One idea?
Always bet on JS
#thanks
Wilson Mendes
@willmendesneto