title: Creating object with calculated values
body: <p>I would like to create an object that has both a stored value and a calculated value in node.</p>
  
  <p>i.e.</p>
  
  <pre><code>function test(value) {
      this.value  = value;
      this.double = this.value * 2;
      this.even   = (this.value % 2 == 0)
  }
  
  var a = new test(1);
  console.log(a);
  </code></pre>
  
  <p>Question: Is this the correct way to achieve this?</p>