title: Are these statements functionally equivalent?
body: <p>As far as I can tell they function the same, but I wanted to make sure. I would like to use the latter statement as it is less code and seems more efficient.</p>
  
  <pre><code>function updateRunningTotals(taxExempt, discType, discAmt){
    if (typeof taxExempt === 'undefined') { taxExempt = false; }
    taxExempt = taxExempt || false;
  }
  </code></pre>
  
  <p>I have been using the <code>if</code>, but I have seen the latter statement in some open source projects. Do they basically do the same thing? Any performance benefit?</p>
  
  <p>EDIT: taxExempt, in this scenario may not always be passed in.</p>