bilby.js promise, I'd assume that you would want to do the following? The only downside I can foresee is that we loose the documentation of fantasy promises (through emu). I could be wrong and it could be a flag for this sort of stuff? You could possibly get rid of rigger for concat of files and just rely on require as well, might be worth exper…

Promise.js

var Promise = require('fantasy-promises');

/**
   ## isPromise(a)

   Returns `true` if `a` is `Promise`.
**/
var isPromise = isInstanceOf(Promise);

bilby = bilby
    .property('Promise', Promise)
    .property('isPromise', isPromise)
    .method('map', isPromise, function(a, b) {
        return a.map(b);
    });