CPS.js

// standardize done arguments with Continuation Passing Style
var createDoneArgs = function(args){
    var doneArgs = [].slice.call(args);
    doneArgs.unshift(undefined);
    return doneArgs;
};

//usage
function(arg1, arg2, npcCallback) {
    var that = this;
    regularAsyncFunction(arg1, arg2, function(){
        npcCallback.apply(that, createDoneArgs(arguments));
    });
}