MongoError:集合名称必须是字符串

在尝试通过post获取数据时,我得到了“mongoerror:collection name must be a string”。以下是我得到的错误:

"
MongoError: collection name must be a String
    at checkCollectionName (/home/rishabh/test/node_modules/mongodb/lib/utils.js:99:11)
    at new Collection (/home/rishabh/test/node_modules/mongodb/lib/collection.js:101:3)
    at Db.collection (/home/rishabh/test/node_modules/mongodb/lib/db.js:335:26)
    at Object.queries.getPlayersList (/home/rishabh/test/dbConnection/queries.js:207:24)
    at playersList (/home/rishabh/test/lib/MonthlyLeaderboard.js:38:11)
    at /home/rishabh/test/node_modules/async/lib/async.js:760:23
    at /home/rishabh/test/node_modules/async/lib/async.js:166:37
    at fn (/home/rishabh/test/node_modules/async/lib/async.js:746:34)
    at /home/rishabh/test/node_modules/async/lib/async.js:1213:16
    at /home/rishabh/test/node_modules/async/lib/async.js:166:37

"

这是代码行编号:

queries.getPlayersList = function(collectionName, query, callback) {
db().db('test').collection(collectionName).find(query.id).sort(query.sortBy).skip(query.skip).limit(parseInt(query.limit) ).toArray(function (err, result) {

        callback(err, result);
    })
}

请告诉我我做错了什么。