A useful function for handling node-style callbacks.

config.js

//Add "ifok" function
global.ifok = function(args, msg, cb){
        var me = this;
        args = Array.prototype.slice.call(args);
        var err = args.shift();
        var log = (me.log || console.log);

        //You can comment out a log message by adding a space at the beginning
        if(msg.length && msg.charAt(0) === ' '){
                msg = null;
        }
        else{
                msg = (err ? '#err: ' : '#ok: ') + msg;
        }

        if(msg){
                log.call(me, msg);
                if(err){
                    log.call(me, err);
                }
        }

        //Delay the callback until after returning the "me" object
        process.nextTick(function(){
                cb.apply(me, args);
        });

        //Return
        return me;

};

I use this to simplify callbacks that have an error as the first parameter (as is node convention).

usage:

db.collection.find({}, function(err, cursor){
    var me = ifok(arguments, 'Continue doing something...', function(cursor){

        // You'll only get to this point if there wasn't an error. 
        // If there was an error, you'll see:
        //   
        //     "#err: Continue doing something..."
        //   
        // In addition, the original "this" object is stored in the "me" variable.

    });
});

Hope this is useful!