node.js dynamodb scan

dal.js

doScan: function (tableName, limit, startKey, callback) {
        limit = typeof limit !== 'undefined' ? limit : null;
        startKey = typeof startKey !== 'undefined' ? startKey : null;
        var self = this;
        var params = {TableName: tableName};
        if (limit != null)
            params.Limit = limit;
        if (startKey != null)
            params.ExclusiveStartKey = startKey;
        var items = [];
        var processNextBite = function (err, items, nextKey) {
            if (nextKey && nextKey != null) {
                params.ExclusiveStartKey = nextKey;
                getNextBite(params, items, processNextBite);
            } else {
                callback(err, items);
            }
        };
        var getNextBite = function (params, items, callback) {
            var result = self.db.scan(params, function (err, data) {
                var obj = null;
                if (err != null) {
                    console.log(err); // TODO better error handling
                    obj = null;
                    callback(err, items, null);
                    return;
                }
                if (typeof data.Items == "undefined") {
                }
                if (data && data.Items && data.Items.length > 0)
                    items = items.concat(data.Items);

                var lastStartKey = null;
                if (data)
                    lastStartKey = data.LastEvaluatedKey;

                callback(err, items, lastStartKey);
            });
        };

        getNextBite(params, items, processNextBite);

    },