seneca.cmds with $ master - proof of concept

gistfile1.txt

//usage: 
cmds({
  $: {general: 'pattern'}, 
  a: {specificying:'pattern'}
})
  .$a(function (err, args) {
     console.log(args, Object.keys(args))
  })

//after 1.5 secs logs  Object {specificying: "pattern", general: "pattern"} ["specificying", "general"]

//concept:

function cmds(patterns) {
   patterns = arguments.length > 1 ? arguments : patterns;
   var api = {};
   var master = patterns.$;
   delete patterns.$;

   setTimeout(function () { 
     Object.keys(api).forEach(function (k) { 
       api[k]._resolve(null, patterns[k.substr(1)]) 
     }) 
   }, 1500)
 
   return Object.keys(patterns).reduce(function (o, k) {
     if (master) {
       patterns[k] = defaults(patterns[k], master);
     }
     o['$'+k] = makeCb(o);
     return o;
   }, api);
}

function makeCb(api) {  
  function caller(cb) {
    if (caller._resolved) {
      cb(caller._err, caller._args);
      return api;
    }
    caller._resolve = function (err, args) {
      resolve(err, args);
      cb(err, args);
    }
    return api;
  }
  function resolve (err, args) {         
     caller._err = err; caller._args = args; 
     caller._resolved = true;
  }
  caller._resolve = resolve;
  return caller;  
}   

function defaults(object, source, guard) {
  var objectTypes = {
    'boolean': false,
    'function': true,
    'object': true,
    'number': false,
    'string': false,
    'undefined': false
  }; 
  var keys = Object.keys;
  var index, iterable = object, result = iterable;
  if (!iterable) return result;
  var args = arguments,
      argsIndex = 0,
      argsLength = typeof guard == 'number' ? 2 : args.length;
  while (++argsIndex < argsLength) {
    iterable = args[argsIndex];
    if (iterable && objectTypes[typeof iterable]) {
    var ownIndex = -1,
        ownProps = objectTypes[typeof iterable] && keys(iterable),
        length = ownProps ? ownProps.length : 0;

    while (++ownIndex < length) {
      index = ownProps[ownIndex];
      if (typeof result[index] == 'undefined') result[index] = iterable[index];
    }
    }
  }
  return result
};