title: python's hasattr in javascript?
body: <p>in javascript:</p>
  
  <pre><code>d={one: false, two: true}
  d.one
  d.two
  d.three
  </code></pre>
  
  <p>I want to be able to differentiate between <code>d.one</code> and <code>d.three</code>. By default they both evaluate to false, but in my case they should not be treated the same.</p>