title: how to differentiate request empty string and null on laravel
body: <p>in php we can do</p>
  
  <pre><code>isset($_POST['name'])
  </code></pre>
  
  <p>so that user submit empty text can be detected.</p>
  
  <p>but in laravel</p>
  
  <pre><code>$request-&gt;has('name')
  </code></pre>
  
  <p>return null on empty string too.</p>
  
  <p>I need to find a way to tell if it is an empty string or the field not posted at all</p>