Can any information (Call back, promise etc) be passed from backend to front end?

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Good day, I’m currently trying to code a account creation form, for obvious reason I need all the MySQL database connection information on the backend, and the whole form is handled on the frontend page. On the front end I call an exported function from the backend web module, however if I try to have the exported function have a call back the code fails. Is there anyway to get a response back to the front end?

I need to handle what the page does if the account creation is successful or not.

Cheers,
Matt

Front End Code:

import { tryToCreateAccount } from 'backend/account.jsw';
export function create_account_clicked(event) 
{
   tryToCreateAccount($w('#input1').value, null, null, function(err, data)
   {
      console.log(data);
   };
}

Back-End Code:

const mysql = require('mysql');
const pool = mysql.createPool(
{
    connectionLimit : 10,
    host            : 'hostname',
    user            : 'user',
    password        : 'pass',
    database        : 'db'
});

export function tryToCreateAccount(login, password, passwordConfirm, callback) 
{
    checkAccountNameAvailable(login, pool, function(err, accountNameAvailable)
 {
        callback(err, accountNameAvailable);
 });

}

function checkAccountNameAvailable(login, pool, callback)
{
 var accountNameAvailable = true;

    console.log("Checking account name", login);

    pool.getConnection(function (err, connection)
 {
        console.log("Made a connection.");

 if(err)
 {
            console.log(err);
 }

        connection.query("SELECT login FROM accounts WHERE login = ?", login, function (err, result)
 {
            console.log("Checking Query Method");

 if (err)
 {
                console.log(err);
                callback(err, null);
 }

 if(result.length > 0) accountNameAvailable = false;
            console.log("returning ", accountNameAvailable);
            callback(null, accountNameAvailable);
            connection.destroy();
 });
 });
}