For the MongoDB node driver, the 2nd param to findOne() is an options object where you can specify sort() [1]. In Stitch, findOne() only accepts a projection argument [2].

[1] http://mongodb.github.io/node-mongodb-native/3.0/api/Collection.html#findOne

[2] https://docs.mongodb.com/stitch/mongodb/actions/collection.findOne/#collection.findOne