asyncified.js

var stack = new Stack(
    function (path) {
        // default return value
        this.return = path;
       
        // after three actions
        var cb = after(3, (function (a,b,c) {
            // if all succeed go next
            if (a && b && c) {
                this.next();
            } else {
                // short circuit to end
                this.floor();
            }
        }).bind(this)); 
        
        path.exists(path + ".js", function (exists) {
            cb (!exists);
        });
        
        path.exists(path, cb);
        
        fs.stat(path, function (err, stats) {
            cb(stats.isDirectory()); 
        });
    },
    function (path) {
        // check path exist
        path.exists(path + "/main.js", function (exists) {
            if (exists) {  
                // set return and short circuit              
                this.return = path + "/main":
                this.floor();
            } else {
                this.next();    
            }
        });
    },
    function (path) {
        path.exists(path + "/index.js", function (exists) {
            if (exists) {
                this.return = path + "/index";
                this.floor(); 
            }  
        });
    } 
);

function extendPath(path, cb) {
    // flow path through stack
    stack.handle({
        data: [path],
        floor: function () {
            // at end of stack send return into cb.
            cb(this.return);    
        }
    });  
}


function _extendPath(_, path) {
       // test three async conditions
       if (!_exists(_, path + ".js") && _exists(_, path) &&
               fs.stat(path, _).isDirectory()) {
               // if either exists return it
               if (_exists(_, path + "/main.js"))
                       return path + "/main";
               else if (_exists(_, path + "/index.js"))
                       return path + "/index";
       }
       // just return path
       return path;
}