Collections In Backbone.js

• Backbone.js Collections are ordered sets of models.
• They represent a group of related data items.
• Collections provide a rich API for working with groups of models, including filtering, sorting, and querying.

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1. What are Backbone.js Collections?

In Backbone.js, collections are used to represent ordered sets of models. They provide a convenient way to work with groups of related data items, such as a list of books or a collection of user comments.

Example:

// Example Backbone.js Collection
var BookCollection = Backbone.Collection.extend({
  model: Book
});

In this example, a Backbone.js collection called BookCollection is defined to manage a collection of Book models.

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2. Creating Backbone.js Collections

To create a Backbone.js collection, you can use the extend() method provided by Backbone.js. You define the collection's properties, including the model property, which specifies the type of model that the collection will contain.

Example:

// Creating a Backbone.js Collection
var TodoList = Backbone.Collection.extend({
  model: Todo
});

In this example, a Backbone.js collection called TodoList is created to manage a collection of Todo models.

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3. Working with Backbone.js Collections

Once created, Backbone.js collections can be used to manage groups of models. You can add, remove, fetch, and manipulate models within the collection. Collections also provide a rich set of methods for querying and filtering data.

Example:

// Using Backbone.js Collection
var todos = new TodoList([
  { title: 'Learn Backbone.js', completed: false },
  { title: 'Build an app', completed: true }
]);

todos.add({ title: 'Write documentation', completed: false });

var completedTodos = todos.where({ completed: true });
var firstTodo = todos.at(0);

In this example, a new instance of the TodoList collection is created and manipulated by adding new models, querying for completed todos, and accessing individual todos by index.

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4. Conclusion

Understanding Backbone.js Collections is essential for managing groups of related data items in your application. By creating and working with collections, developers can easily organize and manipulate sets of models, enabling efficient data management and manipulation.