title: How to access the GET parameters after "?" in Express?
body: <p>I know how to get the params for queries like this:</p>
  
  <pre><code>app.get('/sample/:id', routes.sample);
  </code></pre>
  
  <p>In this case, I can use <code>req.params.id</code> to get the parameter (e.g. <code>2</code> in <code>/sample/2</code>).</p>
  
  <p>However, for url like <code>/sample/2?color=red</code>, how can I access the variable <code>color</code>?</p>
  
  <p>I tried <code>req.params.color</code> but it didn't work.</p>