How to work properly in Node js?

Question

Node.js

Hello uv. community. Please tell me, using an example, how to work correctly in Node js.
Here is the code:

var config = require('./config');
var query = require('./mysql').query;

var res;
query('SELECT test FROM test WHERE id=1 LIMIT 1').then(function (result) {
  if(result){
    res = result[0].test;
    console.log("result = "+res);
  }
}).catch(function (err) {
  console.log('Error');
  console.log(err);
});
console.log("result out = "+res);

Result:
result out = undefined
result = web
I understand that the output line to the console is processed before the result is entered into the variable, but I don’t understand how to implement everything correctly.

Answer 1

So you have everything right and implemented. There are no errors, everything works.
A bit of telepathy:
If you want to work with res - work inside then.
If you want to do something while the request is coming, you do it where you have "result out".