title: Default parameter in angular directive
body: <p>How I can set a default parameter in angular directive?</p>
  
  <p><strong>Here is direcitve in html:</strong></p>
  
  <pre><code>&lt;product product="product" isfavorites="true"&gt;&lt;/product&gt;
  </code></pre>
  
  <p>i want <code>isfavorites</code> have a default value <code>false</code>. so if is not set to <code>true</code> return <code>false</code>.
  How i can do this?</p>