How to get the latest and oldest record in Node Mongoose.js?

To get the latest and oldest record in Node Mongoose.js, we use the sort method.

For instance, we write

Tweet.findOne()
  .sort("-created_at")
  .exec((err, post) => {
    //...
  });

to call sort to sort the results by the created_at field in descending order.

Then we get the latest result from post in the callback.