We should use [_.extend][1] so that if just a few of the options are provided, the remaining options will be set according to the defaults we define:

```coffeescript
options = _.extend
  report: yes
, options
```

Note that I'm suggesting [_.extend][1] rather than [_.defaults][2], as the latter mutates its first argument.


[1]: http://underscorejs.org/#extend
[2]: http://underscorejs.org/#defaults