Backbone.js

Arquitetura sólida para aplicações web

Henrique Antonini Silvério

Analista Front-End na Finch Soluções

  • Twitter: @RikeSilverio
  • Github: github.com/HenriqueSilverio

Backbone.js gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface.

O que é Backbone?

"

"

backbonejs.org

Biblioteca MV*

  • Event
  • Model
  • Collection
  • View
  • Router
  • History
  • Sync

Por que escolher Backbone?

  • Pequeno e robusto.
  • Foco em manipular e consultar dados.
  • Liberdade para escolher qualquer engine de templates.
  • Não te obriga a injetar lógica da aplicação no HTML.
  • Compatível com jQuery e outros.
  • Há mais do que uma única maneira de fazer as coisas.

Quem já utiliza Backbone?

Dependências

Underscore ~ underscorejs.org

jQuery ~ jquery.com

#mimimi não use jQuery... ( http://goo.gl/QR8e13 )

Alternativas:

Lo-Dash ~ lodash.com

Zepto ~ zeptojs.com

Model

Models are the heart of any JavaScript application, containing the interactive data as well as a large part of the logic surrounding it: conversions, validations, computed properties, and access control.

http://backbonejs.org/#Model


  var Book = Backbone.Model.extend({
      defaults: {
          title: '',
          author: ''
      }
  });

  var Book = Backbone.Model.extend({});

Definindo um Model personalizado

Instanciando e Manipulando um Model


  var book1 = new Book({ title: 'Full Stack Web Development with Backbone.js' });

  console.log( book1.get('title') );
  // => 'Full Stack Web Development with Backbone.js'

  book1.set('title', 'Backbone.js Cookbook');

  console.log( book1.get('title') );
  // => 'Backbone.js Cookbook'

  book1.set({
      title: 'Building Backbone Plugins',
      author: 'Derick Bailey'
  });

  book1.toJSON();
  // => Object {title: "Building Backbone Plugins", author: "Derick Bailey"}

Collection

Collections are ordered sets of models.

http://backbonejs.org/#Collection


  var Library = Backbone.Collection.extend({
      model: Book
  });

Declarando uma Collection personalizada

Instanciando e populando:


  var MyLibrary = new Library([
      { title: 'Developing Backbone.js Applications', author: 'Addy Osmani' },
      { title: 'Full Stack Web Development with Backbone.js ', author: 'Patrick Mulder' },
      { title: 'Building Backbone Plugins', author: 'Derick Bailey' }
  ]);

Manipulando uma Collection


  MyLibrary.at(0).toJSON();
  // => 'Developing Backbone.js Applications'

  MyLibrary.pluck('author');
  // => Array [ "Addy Osmani", "Patrick Mulder", "Derick Bailey" ]

  MyLibrary.where({ author: 'Addy Osmani' });
  // => 'Developing Backbone.js Applications'

  MyLibrary.length
  // => 3

View

Organize your interface into logical views, backed (or not) by models...

http://backbonejs.org/#View

Declarando uma View personalizada


  var BookView = Backbone.View.extend({
      tagName: 'div',

      className: 'book-item',

      events: {
          'click .open': 'openClicked'
      },

      initialize: function() {
          console.log('The View has created!');
      },

      openClicked: function(e) {
          console.log( $(e.target) );
      }
  });

  var theBook = new BookView();

  // => 'The View has created!'

View !== Template

Templates entram em ação


  var BookView = Backbone.View.extend({
      // ... tagName, className, events ...
  
      template: _.template( [
          '<b>Title:</b> <%= title %> <br>',
          '<b>Author:</b> <%= author %> <hr>' 
      ].join('') ),
  
      render: function() {
          var data = this.model.toJSON();
          this.$el.html( this.template( data ) );
          return this;
      },

      // ... initialize and other methods ...
  });

Instanciando e Renderizando uma View


  var theBookView = new BookView({ model: theBookModel });

  $('body').html( theBookView.render().el );

  var theBookModel = new Book({ 
      title: 'Backbone.Marionette.js: A Gentle Introduction', 
      author: 'David Sulc' 
  });

Surge a CollectionView

  1. Fazer um loop na `collection`
  2. Criar e renderizar uma `view` para cada model
  3. Inserir o HTML da `CollectionView` no DOM

Interessante... show me the code!


  var LibraryView = Backbone.View.extend({
      tagName: 'ul',

      className: 'books-list',

      render: function() {
          this.collection.each(function(book) {
              var bookItemView = new BookView({ model: book });
              this.$el.append( bookItemView.render().el );
          }, this);

          return this;
      }
  });

Declarando uma CollectionView

Instanciando e Renderizando uma Collection


  var BooksCollection = new Library([
      { title: 'Developing Backbone.js Applications', author: 'Addy Osmani' },
      { title: 'Full Stack Web Development with Backbone.js ', author: 'Patrick Mulder' },
      { title: 'Building Backbone Plugins', author: 'Derick Bailey' },
      { title: 'Backbone.Marionette.js: A Gentle Introduction', author: 'David Sulc' }
  ]);
  
  var theLibraryView = new LibraryView({ collection: BooksCollection });
  
  $('body').html( theLibraryView.render().el );

CollectionView exibida no browser

Events

Events is a module that can be mixed in to any object, giving the object the ability to bind and trigger custom named events.

http://backbonejs.org/#Events

Promove o baixo acoplamento entre os diversos componentes do sistema.

Ex: Views podem "escutar" eventos disparados por Models e Collections e reagir de acordo.


  var Library = Backbone.Collection.extend({

      model: Book,

      resetSelected: function() {
          this.each(function(model) {
              model.set({ selected: false });
          });
      },

      selectByCID: function(cid) {
          this.resetSelected();

          var book = this.get(cid);
          book.set('selected', true);

          return book.cid;
      }
  });

Modificando a Collection e a View


  var BookView = Backbone.View.extend({
      events: {
          'click': 'selectBook'
      },

      initialize: function() {
          this.listenTo( this.model, 'change:selected', this.render );
      },

      render: function() {
          var data = this.model.toJSON();

          this.$el.html( this.template( data ) );
          this.$el.toggleClass( 'selected', this.model.get('selected') );
          
          return this;
      },
      selectBook: function(e) {
          if(!this.model.get('selected')) {
              this.model.collection.resetSelected();
              this.model.collection.selectByCID( this.model.cid );
          }
      }
  });
      // ... tagName, className, template ...

Click!

Change de View!

Router

Backbone.Router provides methods for routing client-side pages, and connecting them to actions and events.

http://backbonejs.org/#Router

Declarando um Router

  
  var AppRouter = Backbone.Router.extend({
      routes: {
          '': 'showHome',
          'book/:id' : 'showBook'
      },
      showBook: function(id) {
          // ... get the book by id
          // ... create and render a view
          // etc
      }
  });
  
  $(function() {
      var appRouter = new AppRouter();
      Backbone.history.start();
  });

Vale a pena conferir também

Quer saber mais?

Backbone.js Resources

A curated compilation of resources to master Backbone.js development.

Backbone.js - Arquitetura sólida para aplicações web

By Henrique Silvério

Backbone.js - Arquitetura sólida para aplicações web

Slides do Workshop ministrado no 4º Encontro FDG Interior, dia 31 de Janeiro de 2015.

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