Another way in which several of the Underscore methods can be used is by extracting a specific Model or Models from a Collection. The simplest way to do this is with the where and findWhere methods, which return all the (or in the case of findWhere, the first) Models that match a provided attributes object. For example, if you want to extract all the books in a Collection, which have exactly one hundred pages, you can use the where method, as shown here:
var books = new Backbone.Collection([
{
pages: 100, title: "Backbone Essentials 5: The Essentials Return"
}, {
pages: 100, title: "Backbone Essentials 6: We're Not Done Yet?"
},{
pages: 25, title: "Completely Fake Title"
}
]);
var hundredPageBooks = books.where({pages: 100});
// hundredPageBooks array of all of the books except Completely Fake Title
var firstHundredPageBook = books.findWhere({pages: 100});
firstHundredPageBook; // Backbone Essentials 5: The...