simplified callback

src/database/mongo/hash.js

@@ -136,14 +136,13 @@ module.exports = function(db, module) {
 	};
 
 	module.incrObjectFieldBy = function(key, field, value, callback) {
+		callback = callback || function() {};
 		var data = {};
 		field = helpers.fieldToString(field);
 		data[field] = value;
 
 		db.collection('objects').findAndModify({_key:key}, {}, {$inc: data}, {new:true, upsert:true}, function(err, result) {
-			if(typeof callback === 'function') {
+			callback(err, result ? result[field] : null);
-				callback(err, result ? result[field] : null);
-			}
 		});
 	};
 };

src/database/redis/sorted.js

@@ -125,11 +125,7 @@ module.exports = function(redisClient, module) {
 		multi[reverse ? 'zrevrange' : 'zrange']('temp', start, stop);
 		multi.del('temp');
 		multi.exec(function(err, results) {
-			if (!err && typeof callback === 'function') {
+			callback(err, results ? results[1] : null);
-				callback(null, results[1]);
-			} else if (err) {
-				callback(err);
-			}
 		});
 	}
 };