Adding attributes to Collections?

[yanneves]

I've looked through the closed 'enhancements' flagged for Backbone, and couldn't find anything on this specific subject, but am wondering whether attributes for Collections is something that's been investigated?

Personally, I could see plenty of utility in being able to provide a small selection of meta data to a collection.

For example, say we have an Album collection of song models:

var Album = Backbone.Collection.extend({
    model: song,
    properties: {
        name: "Greatest Hits",
        publisher: "Sony"
    }
});

the properties attribute could allow something like this:

Album.prop("name"); // "Greatest Hits"
Album.prop("publisher"); // "Sony"

Album.pluck("title"); // "Song1,Song2,Song3..."

Otherwise, at the moment we would have something like this, which relies on that collection being populated:

Album.first().get("albumName"); // "Greatest Hits"

I discovered a similar (old) topic on Stack Overflow: Setting attributes on a collection - backbone js.

Where I can't rely on data being available in a collection, I'm actually having to wrap the collection in a model (model -> collection -> model) to be able to support these meta data attributes.

[braddunbar]

Hi @Aaunel, thanks for your issue! You can certainly accomplish what you're describing without any extra support.

var Album = Backbone.Collection.extend({
  model: Song,
  initialize: function(models, options) {
    _.extend(this, _.pick(options, 'name', 'publisher'));
  }
});
var album = new Album([], {name: 'Greatest Hits', publisher: 'Sony'});
console.log(album.name, album.publisher);  // Greatest Hits, Sony

However, it sounds like what you want is a separate model for storing album attributes. For instance:

var album = new Backbone.Model({name: 'Greatest Hits', publisher: 'Sony'});
album.songs = new Backbone.Collection(...);

I think you'll have more success with that pattern. Hope it helps!

[yanneves]

@braddunbar Thanks for the response. I'm currently wrapping anything that needs these attributes (as well as multi-collection data structures) in models. If that's not considered bad-practice, I'll carry on that way?

Otherwise, that solution above would work perfectly for small selections of metadata.

Cheers!

[jaseemabid]

👍 @braddunbar , the answer helped :)