title: Programmatically adjusting d3 brush with animation
body: <p>How can a D3 brush be programmatically adjusted from extent to extent? Can it be done so it appears to be animated rather than just instantly snapping to a final extent?</p>
  
  <p>For example:</p>
  
  <pre><code>[0,0] to [0,100]
  </code></pre>
  
  <p>Extent just expanding to the right.</p>