title: Return Variable From Function
body: <p>I am a beginner in JS and I have difficulty understanding why the output of my var is "Undefined." My JS runs a GET to download a JSON file and with a function, I am trying to read the file and return the first line:</p>
  
  <pre><code>invest.stock('APPLE', function (err, data) {
        if (err) { console.log('ERROR', err); return; }
        var APPLE_price = data.order[0]['price'];
        console.log(APPLE_price); //until here works fine
  });
      console.log(APPLE_price); //output "Undefined" var
  </code></pre>
  
  <p>I tried declare the var previously, I created a statement to wait the var (because was a async function) but nothing works.</p>