Why do i get 'undefined' at my request in Node and Mongo? - node.js

Question

I'm creating my first API, I've used .env for database variables in this url:
const uri = `mongodb+srv://${mongo_user}:${mongo_pwd}#cluster0.ynvbj.mongodb.net/${mongo_db}?retryWrites=true&w=majority`
then created the client:
const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true })
Then, a main function that calls the functions that finds data from Mongo like users:
async function main() {
try {
await client.connect();
await getUser(client, 'users', mongo_db);
} catch (e) {
console.error(e);
} finally {
await client.close();
}
}
main().catch(console.err);
//------GET
//user by Dni
async function getUser(client, coll, mongo_db){
const collection = await client.db(`${mongo_db}`).collection(`${coll}`)
.find({dni: 38383838}).toArray(function(err, results) {
console.log(results);
return results;
})
};
And finally, I created the routes, but I get undefined. I've check everything and I don't get what's wrong.
const {getUser, getOrder, getProducts} = require('./db_connection')
const {Router} = require('express')
const router = Router()
//GET
//get user
router.get('/users', async (req, res) => {
let data = await getUser;
res.json({data});
})
module.exports = router;
And this is app.js
const express = require('express')
const app = express()
require('dotenv').config();
//settings
app.set('port', process.env.PORT || 3000)
//middlewares
app.use(express.urlencoded({extended:false}))
app.use(express.json())
//server
app.listen(app.get('port'), ()=> {
console.log(`Server running on port ${app.get('port')}`)
})
//require api
app.use('/api', require('./api_routes'))

Answer 1

It looks like your results are undefined, that could be for a lot of different reasons.
Where you have console.log(results) can you replace that with console.debug(err, results);
That might give you more insight into the reason it's not getting the results.
async function getUser(client, coll, mongo_db){
const collection = await client.db(`${mongo_db}`).collection(`${coll}`)
.find({dni: 38383838})
.toArray(function(err, results) {
console.debug(err, results);
return results;
})
};