{"action":"opened","issue":{"url":"https://api.github.com/repos/jashkenas/backbone/issues/3853","labels_url":"https://api.github.com/repos/jashkenas/backbone/issues/3853/labels{/name}","comments_url":"https://api.github.com/repos/jashkenas/backbone/issues/3853/comments","events_url":"https://api.github.com/repos/jashkenas/backbone/issues/3853/events","html_url":"https://github.com/jashkenas/backbone/issues/3853","id":115771351,"number":3853,"title":"More information for 'update' event on collection","user":{"login":"Mordentware","id":7100708,"avatar_url":"https://avatars.githubusercontent.com/u/7100708?v=3","gravatar_id":"","url":"https://api.github.com/users/Mordentware","html_url":"https://github.com/Mordentware","followers_url":"https://api.github.com/users/Mordentware/followers","following_url":"https://api.github.com/users/Mordentware/following{/other_user}","gists_url":"https://api.github.com/users/Mordentware/gists{/gist_id}","starred_url":"https://api.github.com/users/Mordentware/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Mordentware/subscriptions","organizations_url":"https://api.github.com/users/Mordentware/orgs","repos_url":"https://api.github.com/users/Mordentware/repos","events_url":"https://api.github.com/users/Mordentware/events{/privacy}","received_events_url":"https://api.github.com/users/Mordentware/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-11-09T00:11:10Z","updated_at":"2015-11-09T00:11:10Z","closed_at":null,"body":"In both instances where `update` is triggered on a collection (within `remove` method and within `set` method) the code has access to all of the following information:\r\n\r\n* what models were added to the collection (none in `remove` method, the local variable `toAdd` in `set` method)\r\n* what models were removed from the collection (the local variable `removed` in `remove` method, the local variable `toRemove` in `set` method)\r\n* what models were changed in the collection (none in `remove` method, the local variable `set` minus those in `toAdd` in `set` method)\r\n\r\nJust as `previousModels` is included in the options for a `reset` event, would it be possible/sensible to have the above information included on an `update` to allow for some more optimised bulk operations rather than having to do them on `add`, `remove` and `change` respectively?"}}