title: Javascript : Loop through an array starting and ending at different indexs
body: <p>I have a very large array of objects — around 30000.</p>
  
  <pre><code>     randomStart = Math.floor( Math.random() * arr.length ) 
  </code></pre>
  
  <p>I'm selecting a random range from the total length.</p>
  
  <p>what I want to do is loop through the array beginning at <code>randomStart</code> and ending at <code>randomStart + n</code>. </p>
  
  <p><em>Note</em>:
  This array <em>must</em> stay intact, because it's too computationally expensive to re-render the entire set. </p>
  
  <p>What's the best way to go about this ? What looping paradigm should be used : <code>for</code>, <code>while</code>, etc  </p>