Ember 2.0 components - attribute naming convention

Is there a convention or preferred naming convention for component attributes?

I have seen dasherized:

{{my-component initial-selection='...' on-selected=(action '...') }}

and camel cased:

{{my-component initialSelection='...' onSelected=(action '...') }}

I would have thought ember, being an opinionated framework, would enforce at least one of these naming conventions.