title: What is this JS syntax? Assignment in expression? (x != null && (y = x))
body: <p>I'm working with this JS plugin, and I've encountered some syntax I've never seen before. I understand what it's doing, but I'm not sure why it works.</p>
  
  <p>Here's an example of one instance of it:</p>
  
  <pre><code>settings.maxId != null &amp;&amp; (params.max_id = settings.maxId);
  </code></pre>
  
  <p>Is this just taking advantage of conditionals and the single = ? Is this common syntax for JS?</p>