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todos.js

An example Backbone application contributed by Jérôme Gravel-Niquet. This demo uses a simple LocalStorage adapter to persist Backbone models within your browser.

 
             		           
                               
                            
                                
               
Load the application once the DOM is ready, using jQuery.ready:
             		                            
$(function(){
             		           
                               
                            
                                
               
Todo Model
             		                            
             		           
                               
                            
                                
               
Our basic Todo model has text, order, and done attributes.
             		                            
  window.Todo = Backbone.Model.extend({
             		           
                               
                            
                                
               
Default attributes for a todo item.
             		                            
    defaults: function() {
      return {
        done:  false,
        order: Todos.nextOrder()
      };
    },
             		           
                               
                            
                                
               
Toggle the done state of this todo item.
             		                            
    toggle: function() {
      this.save({done: !this.get("done")});
    }

  });
             		           
                               
                            
                                
               
Todo Collection
             		                            
             		           
                               
                            
                                
               
The collection of todos is backed by localStorage instead of a remote
server.
             		                            
  window.TodoList = Backbone.Collection.extend({
             		           
                               
                            
                                
               
Reference to this collection's model.
             		                            
    model: Todo,
             		           
                               
                            
                                
               
Save all of the todo items under the "todos" namespace.
             		                            
    localStorage: new Store("todos"),
             		           
                               
                            
                                
               
Filter down the list of all todo items that are finished.
             		                            
    done: function() {
      return this.filter(function(todo){ return todo.get('done'); });
    },
             		           
                               
                            
                                
               
Filter down the list to only todo items that are still not finished.
             		                            
    remaining: function() {
      return this.without.apply(this, this.done());
    },
             		           
                               
                            
                                
               
We keep the Todos in sequential order, despite being saved by unordered
GUID in the database. This generates the next order number for new items.
             		                            
    nextOrder: function() {
      if (!this.length) return 1;
      return this.last().get('order') + 1;
    },
             		           
                               
                            
                                
               
Todos are sorted by their original insertion order.
             		                            
    comparator: function(todo) {
      return todo.get('order');
    }

  });
             		           
                               
                            
                                
               
Create our global collection of Todos.
             		                            
  window.Todos = new TodoList;
             		           
                               
                            
                                
               
Todo Item View
             		                            
             		           
                               
                            
                                
               
The DOM element for a todo item...
             		                            
  window.TodoView = Backbone.View.extend({
             		           
                               
                            
                                
               
... is a list tag.
             		                            
    tagName:  "li",
             		           
                               
                            
                                
               
Cache the template function for a single item.
             		                            
    template: _.template($('#item-template').html()),
             		           
                               
                            
                                
               
The DOM events specific to an item.
             		                            
    events: {
      "click .check"              : "toggleDone",
      "dblclick div.todo-text"    : "edit",
      "click span.todo-destroy"   : "clear",
      "keypress .todo-input"      : "updateOnEnter"
    },
             		           
                               
                            
                                
               
The TodoView listens for changes to its model, re-rendering.
             		                            
    initialize: function() {
      this.model.bind('change', this.render, this);
      this.model.bind('destroy', this.remove, this);
    },
             		           
                               
                            
                                
               
Re-render the contents of the todo item.
             		                            
    render: function() {
      $(this.el).html(this.template(this.model.toJSON()));
      this.setText();
      return this;
    },
             		           
                               
                            
                                
               
To avoid XSS (not that it would be harmful in this particular app),
we use jQuery.text to set the contents of the todo item.
             		                            
    setText: function() {
      var text = this.model.get('text');
      this.$('.todo-text').text(text);
      this.input = this.$('.todo-input');
      this.input.bind('blur', _.bind(this.close, this)).val(text);
    },
             		           
                               
                            
                                
               
Toggle the "done" state of the model.
             		                            
    toggleDone: function() {
      this.model.toggle();
    },
             		           
                               
                            
                                
               
Switch this view into "editing" mode, displaying the input field.
             		                            
    edit: function() {
      $(this.el).addClass("editing");
      this.input.focus();
    },
             		           
                               
                            
                                
               
Close the "editing" mode, saving changes to the todo.
             		                            
    close: function() {
      this.model.save({text: this.input.val()});
      $(this.el).removeClass("editing");
    },
             		           
                               
                            
                                
               
If you hit enter, we're through editing the item.
             		                            
    updateOnEnter: function(e) {
      if (e.keyCode == 13) this.close();
    },
             		           
                               
                            
                                
               
Remove this view from the DOM.
             		                            
    remove: function() {
      $(this.el).remove();
    },
             		           
                               
                            
                                
               
Remove the item, destroy the model.
             		                            
    clear: function() {
      this.model.destroy();
    }

  });
             		           
                               
                            
                                
               
The Application
             		                            
             		           
                               
                            
                                
               
Our overall AppView is the top-level piece of UI.
             		                            
  window.AppView = Backbone.View.extend({
             		           
                               
                            
                                
               
Instead of generating a new element, bind to the existing skeleton of
the App already present in the HTML.
             		                            
    el: $("#todoapp"),
             		           
                               
                            
                                
               
Our template for the line of statistics at the bottom of the app.
             		                            
    statsTemplate: _.template($('#stats-template').html()),
             		           
                               
                            
                                
               
Delegated events for creating new items, and clearing completed ones.
             		                            
    events: {
      "keypress #new-todo":  "createOnEnter",
      "keyup #new-todo":     "showTooltip",
      "click .todo-clear a": "clearCompleted"
    },
             		           
                               
                            
                                
               
At initialization we bind to the relevant events on the Todos
collection, when items are added or changed. Kick things off by
loading any preexisting todos that might be saved in localStorage.
             		                            
    initialize: function() {
      this.input    = this.$("#new-todo");

      Todos.bind('add',   this.addOne, this);
      Todos.bind('reset', this.addAll, this);
      Todos.bind('all',   this.render, this);

      Todos.fetch();
    },
             		           
                               
                            
                                
               
Re-rendering the App just means refreshing the statistics -- the rest
of the app doesn't change.
             		                            
    render: function() {
      this.$('#todo-stats').html(this.statsTemplate({
        total:      Todos.length,
        done:       Todos.done().length,
        remaining:  Todos.remaining().length
      }));
    },
             		           
                               
                            
                                
               
Add a single todo item to the list by creating a view for it, and
appending its element to the <ul>.
             		                            
    addOne: function(todo) {
      var view = new TodoView({model: todo});
      $("#todo-list").append(view.render().el);
    },
             		           
                               
                            
                                
               
Add all items in the Todos collection at once.
             		                            
    addAll: function() {
      Todos.each(this.addOne);
    },
             		           
                               
                            
                                
               
If you hit return in the main input field, and there is text to save,
create new Todo model persisting it to localStorage.
             		                            
    createOnEnter: function(e) {
      var text = this.input.val();
      if (!text || e.keyCode != 13) return;
      Todos.create({text: text});
      this.input.val('');
    },
             		           
                               
                            
                                
               
Clear all done todo items, destroying their models.
             		                            
    clearCompleted: function() {
      _.each(Todos.done(), function(todo){ todo.destroy(); });
      return false;
    },
             		           
                               
                            
                                
               
Lazily show the tooltip that tells you to press enter to save
a new todo item, after one second.
             		                            
    showTooltip: function(e) {
      var tooltip = this.$(".ui-tooltip-top");
      var val = this.input.val();
      tooltip.fadeOut();
      if (this.tooltipTimeout) clearTimeout(this.tooltipTimeout);
      if (val == '' || val == this.input.attr('placeholder')) return;
      var show = function(){ tooltip.show().fadeIn(); };
      this.tooltipTimeout = _.delay(show, 1000);
    }

  });
             		           
                               
                            
                                
               
Finally, we kick things off by creating the App.
             		                            
  window.App = new AppView;

});