According to the Backbone.js docs

> The changed property is the internal hash containing all the attributes that have changed since the last set. Please do not update changed directly since its state is internally maintained by set. A copy of changed can be acquired from changedAttributes.

The `changed` property is involved in decisions about whether or not a collection should be resorted when it is updated. If you modify it manually, you can break the resorting of the collection.

## Noncompliant Code Example

    myModel.changed = { myProperty: 1 }; // Non-compliant