Properly override clone about backbone.virtualcollection HOT 5 CLOSED

That's a good question @wilfriedvanasten. It brings to light the fact that I didn't really design this with inheritance in mind. Like you mentioned, cloning with all the options can have unintended side effects (in particular you lose control over the close_with option).

Can you tell me a little more about your usecase? What are you trying to achieve?

from backbone.virtualcollection.

Well the mentioned issue actually arose from using a BackGrid Extension for filtering that relied on clone to provide a cloned collection to do the filtering on. I now realize that my proposed implementation would actually result in disaster since the extension would likely use the clone to either 1) maintain the original collection or 2) to represent the filtered contents. Since it would be modifying the collection using virtual collection in either case would result in modification to the underlying collection which is totally wrong. So I will not use that extension and instead write something that works with virtual collection's filtering capabilities instead.

It does however show an interesting apparently expected behaviour of clone: That the resulting collection be completely independent of the original collection. By being bound to the underlying collection this would be hard for a "natural clone" of a virtual collection to provide. So in that sense the best approximation would actually be for clone to return a new Backbone.Collection based on the virtual collections models instead. However than the filtering behaviour would not be maintained which someone who calls VirtualCollection.clone might expect. This issue is more hairy then I initially thought.

from backbone.virtualcollection.

Yep, I get your point.

I think what would make most sense is to return a Backbone.Collection and be done with it. If what you want is a dynamic virtual collection with the same filter, we'll leave it up to the user. Because you'll need to manage the listener lifespan as well, etc. It's really not complicated, but it varies depending on your implementation.

I think it's just a matter of changing return new this.constructor for return new this.collection.constructor. But if you make a PR with tests I'll be happy to merge it.

from backbone.virtualcollection.

Ok, I'm not sure this is terribly useful, but I added support for clone. At least it doesn't throw an error.

from backbone.virtualcollection.

2e5e2fd

from backbone.virtualcollection.