masylum/backbone.subset

Provides a collection-like constructor that allows you create a collection that is subset from a parent one

backbone.subset's Issues

Backbone.Subset does not correctly extend Backbone.Collection

If you create a new instance of a Backbone.Subset, it does not act as an instance of a Backbone.Collection:

!(mySubset instanceof Backbone.Collection) === true

This is a problem because it means you can't always substitute a Subset for a Collection. Knockback, for instance, can't make a collectionObservable around a Subset because it does an instanceof safety check.

parent() called in constructor, but impossible to set from constructor

As seen here: https://github.com/masylum/Backbone.Subset/blob/master/backbone.subset.js#L23-26

Backbone.Subset = function Subset(models, options) {
    options = options || {};

    this.model = this.parent().model;

The trouble with this is it effectively turns instances of Backbone.Subset into singletons, you have to define:

SomeSubset.prototype.parent = function() { /*....*/ }

In such a way that it is very aware of the program implemented around it.

The data inside the instances of a class ought to be passed into the constructor, not the implementation of the class itself.

recalculate bug?

In the reduce function of Subset.recalculate, short-circuit evaluation is causing the right side of:

return changed || self._updateModelMembership(model, {silent: true})

to never be eval'd once changed becomes true. This causes sieve to not be called on each element.

Most likely want:

return self._updateModelMembership(model, {silent: true}) || changed;

`_reset` is called before Collection Constructor

It may be a documentation issue, or it may be a bug, I can't tell.

Line 59 results in an error because this.models (usually set in the Backbone.Collection constructor) hasn't been set yet. I'm not 100% sure what solution to suggest (thus why it's not a pull request) since I'm not really sure if it's a bug or documentation issue. Either way it's worth fixing because this is a very handy, well written tool.

Steps to Reproduce:

coll = new Backbone.Collection([], {})
new Backbone.Subset([], {parent: coll, sieve: function(m) { return true; }})

This happens whether or not you pass in the undocumented no_reset option. If no_reset is true the error fires at line 152

_byCid and inheritance

It appears this repo has gone dormant. I've been using this plugin for awhile, and fixed a couple bugs.

1. Since _byCid was deprecated, the _updateModelMembership function broke. This has been fixed.

2. When extending from a parent collection, the subset was not inheriting any extra properties that may have been set on it. This has also bee fixed.

Fork is here: https://github.com/sarink/Backbone.Subset - I will try to keep updating Pau's code as necessary because I still like this little subset library!