you could make this easier to read if it was structured like this

```javascript
var SUCCEEDED = ['2xx'],
    FAILED = ['3xx', '4xx', '5xx'];

var succeeded = this.get('statusRollupFilterSucceeded'),
    failed = this.get('statusRollupFilterFailed'),
    filters = [];

if (succeeded) {
    _.extend(filters, SUCCEEDED);
}
if (failed) {
    _.extend(filters, FAILED);
}

this.changeStatusRollupFilter(filters);
```