How likely is it that we'll be adding and modifying defaults here?

If we anticipate modifying this more, we could always try a pattern like:

```javascript
const DEFAULTS = {
  user = "mozilla",
  // ...
}

function assignDefaultOptions( options ) {
  options = options || {};

  for ( var option in DEFAULTS ) {
    options[ option ] = options [ option ] || DEFAULTS[ option ];
  }
}
```