crash

course

Node.js

agenda

[
    "Kick Off",
    "Hands-On Coding",
    "Review & Next Steps"
]

HOW DOES node.js WORK?

what is node?

why node?

Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

nodejs.org

"

"

non-blocking

i/o

Database (MongoDB, CouchDB, Redis)

Third-party APIs (Twitter, Facebook, APNS)

Websockets (real-time)

Files (image resizer, video editor)

read data from Facebook API
process data
send data to the client

tasks

callbacks

non-linear thinking

pseudocode

callbacks

non-linear thinking

var data = load(...)
var info = process(data)
send(info)

What would happen if we ran this in Node?

node

callbacks

non-linear thinking

load(function loaded(data) {
    process(data, function processed(info) {
        send(info)
    })
})

Node follows the 'observer' pattern

frontend

node

target.addEventListener('click', function(e) {...});

response.on('data', function(d) {...});

events

One-to-one dependency

callbacks

events

comparison

Many-to-many "subscription" API

command line

node

...is the package manager for node

npm

(pedantic note: npm does not stand for node package manager)

(duh)

...live at

... & express, grunt-cli, etc.

/usr/local/bin

command line

...is the version manager for node

nvm

(side note: this is more important now that io.js exists)

modules

third-party

connect is

built-in

express is connect plus templating

http.Server

plus static

plus over 130,000 more

(disclaimer: over-simplification)

http(s), fs, url, events

modules

how modules work

// model.js
var User = function(name, email) {
  this.name = name;
  this.email = email;
};

// someRoute.js
var Model = require('./model');
var u = new Model.User();

module.exports.User = User;

how modules work

// user.js
var User = function(name, email) {
  this.name = name;
  this.email = email;
};

// someRoute.js
var User = require('./user');
var u = new User();

module.exports = User;

(see the difference?)

folders as modules

organizing your code

index.js

package.json

(1)

(2)

how modules work

one more thing...

require()

modules that you

are cached

based on file name

modules

a few favorites...

async

for tasks in a series or in parallel

lodash

for "functional"

/

underscore

tasks like mapping and filtering

passport

for managing authentication

express

A QUICK DETOUR...

REST

GET

retrieves a resource or collection

POST

creates member(s) of a collection

(disclaimer: over-simplification)

REST

GET

http://.../api/coll

...to retrieve a collection

GET

http://.../api/coll/1

...to retrieve specific resource

A QUICK DETOUR...

(disclaimer: over-simplification)

REST

http://.../api/coll

POST

...to create or update a resource

{ 
    "someKey": "someValue"
}

A QUICK DETOUR...

(disclaimer: over-simplification)

express

// app.js
var express = require('express');
var app = express();
app.listen(1337);

node app.js

npm install express --save

(1)

(2)

(3)

express

your app

// app.js
var express = require('express');
var app = express();

app.listen(1337);

// app.js
var express = require('express');
var app = express();

app.listen(1337);

routing logic

where do requests go?

app.get('/', function(req, res, next) {
    res.status(200).send('hello world');
})

// app.js
var express = require('express');
var app = express();

app.listen(1337);

routing logic

using regular expressions

app.get('/:id([A-Za-z0-9]{10})', function(req, res, next) {
    res.status(200).send('hello ' + req.params.id);
});

app.all('/*', function(req, res, next) {
    res.status(200).send('hello world');
});

// app.js
var express = require('express');
var app = express();

app.listen(1337);

routing logic

chaining

app.all('/*', function(req, res, next) {
    // authentication logic => 401 or...
    next();
});

app.get('/*', function(req, res, next) {
    res.status(200).send('hello world');
});

routing logic

advanced topics

vhost

for routing to subdomains

express.Router

to make your

routing logic modular, given a path

Request

function(req, res, next) { ... }

an incoming object

middleware

response

function(req, res, next) { ... }

the outgoing response

middleware

coming up

function(req, res, next) { ... }

go to the next handler, but...

middleware

middleware

// app.js
var express = require('express');
var app = express();

app.listen(1337);

where does it fit in?

app.get('/', function(req, res, next) {
    /* this is middleware */
});

middleware

which came first?

// app.js
var express = require('express');
var app = express();

app.listen(1337);

app.get(/** 404 middleware **/);

app.get(/** static middleware **/);

rendering with templates

templates

using jade

// base.jade
html
  head
    title Hello World
    link(rel='stylesheet', href='/css/base.css')
    block head
  body
    block body
    script(src='/js/base.js')

// index.jade
extends base
append body
  h1 #{message}

templates

using jade

// app.js
var express = require('express');
var jade = require('jade');
var app = express();

app.listen(1337);

app.set('views', './views');
app.set('view engine', 'jade');

app.get('/', function (req, res) {
  res.render('index', { message: 'Hello world!'});
});

hands-on

bitly.com/thinkful-media-app