Nodejs REST API function throws error "Callback is not a function" - node.js

Question

I am writing a node app's REST API using Sqlite3. The app will have accounts, and the user should be able to create and update one. My code for creating and fetching accounts works as intended, but my update function throws the error: "TypeError: callback is not a function"
The backend is split in two files; db.js – where I set up the database and create the base function for get/post/put/delete, and app.js – where I call the function from db and perform validation checks.
when i run the function in postman, i get error code 500. in vscode, the terminal reads:
Project/rbrneck/rbrneck-backend/db.js:124
callback([], updatedAccount)
^
TypeError: callback is not a function
at Statement.db.run
code:
//in db.js
exports.updateAccountById = (id, updatedAccount, callback) => {
const query = 'UPDATE accounts SET username = ?, password = ? WHERE id = ?'
const values = [
id,
updatedAccount.username,
updatedAccount.password
]
db.run(query, values, (error) => {
if(error) {
if(error.message == "SQLITE_CONSTRAINT: UNIQUE constraint failed: accounts.username") { //username taken
callback(['usernameTaken'])
} else {
callback(['databaseError'])
}
} else {
//const accountUpdated = (this.changes == 1)
callback([], updatedAccount) //HERE IS THE CALLBACK THE ERROR IS REFERRING TO
}
})
}
// in app.js:
app.put('/accounts/:id', (req, res, next) => {
const id = req.params.id
const updatedAccount = req.body
//errors and validation
//type of input
if(typeof(updatedAccount.username) !== 'string' && typeof(updatedAccount.password) !== 'string') {
res.status(422).json({
message: 'Unprocessable Entry'
}).end()
return
}
//does the account exist?
db.getAccountById(id, (errors, oldAccount) => {
if(errors.length > 0) {
res.status(500).json({
message: 'Internal Server Error'
}).end()
return
} else if (!oldAccount) {
res.status(404).end()
return
}
})
//validation:
const validationErrors = []
if(updatedAccount.username.length < USERNAME_MIN_LENGTH) {
validationErrors.push('Username too short')
} else if (updatedAccount.username.length > USERNAME_MAX_LENGTH) {
validationErrors.push('Username too long')
}
if(updatedAccount.password.length < PASSWORD_MIN_LENGTH) {
validationErrors.push('Password too short')
} else if (updatedAccount.password.length > PASSWORD_MAX_LENGTH) {
validationErrors.push('Password too long')
}
if(validationErrors.length > 0) {
res.status(400).json(validationErrors).end()
return
}
db.updateAccountById(updatedAccount, (errors, userId) => {
if(errors.length == 0) {
res.setHeader('Location', '/accounts/' + userId)
res.status(201).end()
} else if (errors.includes('usernameTaken')) {
res.status(400).json(errors).end()
} else {
res.status(500).end()
}
})
})