title: Need explanation of some magic numbers
body: <p>i found this piece of code in the internet</p>
  
  <pre><code>var b = '12-0-17-2-4-11-14';
  var xxx = b.split('-').map(function (x) {
    var x = Number(x); 
    return String.fromCharCode(x &lt; 26 ? 97 + x : 39 + x);
  }).join('');
  console.log(xxx);
  </code></pre>
  
  <p>being:</p>
  
  <pre><code>0 = "a";
  b = "1";
  c = "2";
  d = "3";
  </code></pre>
  
  <p>The output of this code will be 'Marcelo', cause </p>
  
  <pre><code>12 = "M", 0 = "a",  17 = "r", 2 = "c", 4 = "e", 11 = "l", 14 = "o";
  </code></pre>
  
  <p>I understand until transform all the strings into numbers, but the rest a im not catching </p>
  
  <p>What the fromCharCode<code>(x &lt; 26 ? 97 + x : 39 + x)</code> is doing? This pieace of code is responsible for match the numbers with the alphabet.</p>
  
  <p>Can someone explain me? </p>