title: Swap Case on javascript
body: <p>I made a script that changes the case, but result from using it on text is exactly the same text, without a single change. Can someone explain this?</p>
  
  <pre><code>var swapCase = function(letters){
      for(var i = 0; i&lt;letters.length; i++){
          if(letters[i] === letters[i].toLowerCase()){
              letters[i] = letters[i].toUpperCase();
          }else {
              letters[i] = letters[i].toLowerCase();
          }
      }
     console.log(letters);
  }
  
  var text = 'So, today we have REALLY good day';
  
  swapCase(text);
  </code></pre>