Node js: res.json not displaying anything - node.js

Question

I would like to fetch all the data (users) from a localdb using mongodb and node.js. but res.json(usersArray) is not displaying anything. I also tried to use .render but it would give me another error.
var express = require('express');
var mongojs = require('mongojs');
var db = mongojs('mongodb://localhost/mydb', ['users']);
var app = express();
const port = 5000;
app.use(express.static(__dirname + "/public"));
app.get('/', function(req, res){
console.log("I received a GET request")
/*
db.users.find(function(err, docs){
console.log("Getting data from db");
console.log(docs);
//res.json(docs);
});
*/
let usersArray = db.users.find().toArray(function(err, docs){
console.log("Getting data from db");
console.log(docs);
//res.json(docs);
});;
res.json(usersArray);
//usersString = JSON.stringify(usersArray);
//res.render(usersString);
//res.json(usersString);
console.log("Returned data");
});
app.listen(port,'0.0.0.0');
console.log('Server running on port '+port);

Answer 1

use async await to block promise-based asynchronous functions
app.get('/', async function(req, res){
console.log("I received a GET request")
let usersArray = await new Promise((resolve, reject) => {
db.users.find().toArray((err, docs) => {
if (err)
reject(err)
resolve(docs)
})
});
res.json(usersArray);
//usersString = JSON.stringify(usersArray);
//res.render(usersString);
//res.json(usersString);
console.log("Returned data");
});