Hi!
There's a Johnny Five IO plugin: https://github.com/gunderson/omega2-io (i love J5 
)
It "simply" wrap fast-gpio exec, for ex: require( 'child_process' ).spawn( 'fast-gpio', params );
If you don't want to use J5, you can code you own js driver (see https://github.com/gunderson/omega2-io/blob/master/lib/omega2.js#L97)
(I haven't test it for now)
