backbone/toggle

(function(){
  var Task = Backbone.Model.extend({
  	defaults: {
  		title: "sample",
  		completed: false
  	},
  	toggle: function(){
  		this.set("completed", !this.get("completed"));
  	}
  });
  
  var task1 = new Task({
  	completed: true
  });
  console.log(task1.toJSON());
  task1.toggle();
  console.log(task1.toJSON());
})();