title: Javascript perf to clean an array
body: <p>I just took a look to that:</p>
  
  <p><a href="http://jsperf.com/array-destroy/32" rel="noreferrer">http://jsperf.com/array-destroy/32</a></p>
  
  <p>I don't understand how the first one:</p>
  
  <pre><code>arr.length = 0;
  </code></pre>
  
  <p>Can be slower than:</p>
  
  <pre><code>while (arr.length &gt; 0) {
    arr.shift();
  }
  </code></pre>
  
  <p>Someone could link/explain why?</p>