r for riak in node

function returnPosts(postKeys, req, res){
	
	//sys.puts('postKeys:' + postKeys);
	
	var inputs = [];
	for (var i=0;i < postKeys.length;i++){
		var bk = ["posts", postKeys[i].toString() ];
		//sys.puts('bk: '+bk);
		inputs.push(bk);
		
	}
	
	//sys.puts('inputs:' + JSON.stringify(inputs));
	
	var map = function(v, keydata, args) {
	  if (v.values) {
	    var ret = [];
	    o = Riak.mapValuesJson(v)[0]; 	    
	    o.lastModifiedParsed = Date.parse(v["values"][0]["metadata"]["X-Riak-Last-Modified"]);
	    o.key = v["key"];
	    //o.lastModified = v["values"][0]["metadata"]["X-Riak-Last-Modified"];
	    ret.push(o);
	    return ret;
	  } else {
	    return [];
	  }
	};
	
	var reduceDescending = function ( v , args ) {
		
		v.sort ( function(a,b) { return b['lastModifiedParsed'] - a['lastModifiedParsed'] } );
		return v
	};
	
	riak
	.map(map)
	.reduce(reduceDescending)  
	.run(inputs)(function(response) {
	    //sys.puts(JSON.stringify(response));
	    
	    res.simpleJSON(200, response );
	
	  });
	
}