Filtering a Backbone Collection returns an array of Models

问题

Sample Code:

this.books = this.getBooksFromDatabase();
this.publishedBooks = this.books.filter(function(book) {
  return book.get("isPublished") === "1";
});

Here lies the problem:

this.books.filter, returns an array of the models. I've tried wrapping the array, as such:

var publishedBooks = _( this.books.filter(function(book) {
  return book.get("isPublished") === "1";
}))

as recommended by this post: https://github.com/documentcloud/backbone/issues/120

But i still can't run things like: publishedBooks.each(...), or publishedBooks.get(...)

What am I missing? Is there a way to convert the returned array into a collection?

回答1:

You could either instantiate a new backbone collection and pass in the array.

var myPublishedBooks = new MyBooksCollection(publishedBooks);

Or you could refresh your original collection.

this.books.refresh(publishedBooks)

---

Note that the 0.5.0 release in July 2011 renamed refresh to reset, so you can achieve this in newer versions of Backbone with;

this.books.reset(publishedBooks)

回答2:

var collection = new Backbone.collection(yourArray)

回答3:

I often do something like this:

var collection = new MySpecialCollection([...]);
//And later...
var subset = new collection.constructor(collection.filter(...));

This will create an instance of the same type as your original collection, with the filtered models, so you can continue with the collection methods (each, filter, find, pluck, etc).

来源：https://stackoverflow.com/questions/6414976/filtering-a-backbone-collection-returns-an-array-of-models