module.exports with mongodb query returning undefined

I’m creating a module for recording a purchased item on MongoDB using module.exports. This is my first time using this module.exports.

I need to return the results of the updateOne() query because I need to use the modifiedCount information on my main.js. However, the results are returning as undefined. I read that I should either use a callback or promise, with promise being better. How do I exactly do that on my case?

Here’s my code from recordPurchase.js module:

const recordPurchase = (userid, item, price) => {
    db.collection("users").updateOne({ userid: userid }, { $push: { purchases: { item: item, price: price } } })
        .then((result) => {
            if (result.modifiedCount > 0) {
                console.log("Success");
                return result; //return the updateone information
            }
        })
        .catch((err) => {
            console.log("Error recording purchase: " + err)
        })
}

module.exports = recordPurchase;

And here’s how I’m calling it on the main.js

  if (msg.content === "test") {
    const userid = "12345";
    const item = "Some item name";
    const price = 10;
    const result = recordPurchase(userid, item, price)
    console.log(result); //returns updateone/result information
  }