Boxon.cast( fs.readfile, 'myfile' )
  .then( function( content ){ console.log( content ) })
  .catch( function( err ){ console.log( "Error", err ) });

Boxon is promise implementation agnostic, works with Q, bluebird, etc... See https://github.com/JeanHuguesRobert/l8/wiki/AboutBoxons