Discord.js MongooseError: Callback must be a function, got [object Object]

So, I'm adding a premium remove command, so that I can remove premium from users at any given time. However, I tried it and it responded with this error:

Discord.js MongooseError: Callback must be a function, got [object Object]

How can I fix this?

await mongo().then(async (mongoose) => {
        try {
            await premiumSchema.deleteOne({
                userID: user.id
            }, {
                userID: user.id,
                username: user.username
            }, {
                upsert: true
            })
        } finally {
            mongoose.connection.close();
        }
    })

.deleteOne() accepts three parameters; a filter object, an options object, and a callback function. You pass an object as the third parameter ({ upsert: true }) and that's why Mongo is complaining that a callback must be a function, got [object Object].

It looks like you just replaced an updateOne or findOneAndUpdate method with a deleteOne and haven't checked the documentation how to use it.

I'm not sure what you're trying to delete. If it's a document with a certain userID, you can use the following:

try {
  await premiumSchema.deleteOne({ userID: user.id });
} finally {
  // ...
}