Misunderstanding in scope of function

Question

Hello, I am developing a structure to start developing in Ode, I am beginner so forgive me anything.

indexModel.js

var Model = require('./model.js');

var model = new Model();
var data;

class IndexModel {
    // Função inicial
    constructor() {
    }
    // Data banco
    banco() {
        return model.Query('SELECT * FROM test WHERE id = ?', [2], 'select');
    }
    // Retorne a data;
    data() {
      return data;
    }
}

model js.:

var mysql = require('mysql');
var data;

var con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "root",
  database: "nodejs",
  timezone: "-3:00"
});

class ModelModel {
    // Função inicial
    constructor() {
        con.connect(function(err) {
          if (err) throw err;
          console.log("Connected!");
        });
    }
    // Retorna o valor da query passada
    Query(query, array, type) {
        con.query(query, array, function (error, results, fields) {
          if (error) throw error;
          switch (type) {
            case 'select':
                data = results;
                break;
            case 'insert':
                data = results.insertId;
                break;
            case 'update':
                data = 'changed ' + results.changedRows + ' rows';
                break;
            case 'delete':
                data = 'deleted ' + results.affectedRows + ' rows';
                break;
            default:
                data = results;
                break;
          }
        });
        return data;
    }
    ReturnQuer(result) {
        data = result;
        console.log('aqui'+data);
    }
}

I need to receive the date value outside the function, however I always receive 'Undefined', within the function I am receiving everything correctly, I wonder if there is a way to receive the result of the query Return, or if I am doing something wrong.

NOTE: I removed 'use Strict' and module.Exports because for some reason I can’t add it in the stackoverflow text tool as code.