title: Instance of "class" still exists after attempting to destroy it?
body: <p>What is the appropriate way to destroy an instance of a "class" in JavaScript? I'm using node to "require" my classes and its prototypes. And I noticed, setting the instance of the class to equal <code>null</code> does not seem to actually destroy the instance. </p>
  
  <p>E.g.:</p>
  
  <p><strong>The class</strong></p>
  
  <pre><code>function coolClass(){
      this.bob = 'Hey, this is Bob. I should be destroyed, right?!';
      this.init();
  
      console.log('Cool class has been initialized!');
  }
  
  coolClass.prototype.init = function(){
      var self = this;
      this.culprit = setInterval(function(){
          console.log(self.bob);
      },1000);
  }
  
  exports.coolClass = coolClass;
  </code></pre>
  
  <p><strong>Creating &amp; attempting to destroy instance</strong></p>
  
  <pre><code>var coolClass = require('coolClass');
  
  var instance = new coolClass();
  
  setTimeout(function(){
      instance = null;
  },5000);
  </code></pre>
  
  <p>My expectations were that once the timer's function was ran, the <code>coolClass</code> instance would be destroyed; however, it seems that I am wrong.</p>
  
  <p>Any ideas on how to completely remove the instances?</p>
  
  <p>Thanks!</p>