title: If clause in JSX map function
body: <p>So i have this code to generate multiple dropdown lists.</p>
  <pre><code>&lt;div&gt;
    {['Mischung', 'Menge'].map((key) =&gt; (
      &lt;select key={key}&gt;
        {mischung.map(({ [key]: value }) =&gt; (
          &lt;option key={value}&gt;{value}&lt;/option&gt;
        ))}
      &lt;/select&gt;
    ))}
  &lt;/div&gt;
  </code></pre>
  <p>Every dropdown list is beeing generated, but with empty values.</p>
  <p><a href="https://i.stack.imgur.com/jjhSM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jjhSM.png" alt="enter image description here" /></a></p>
  <p><a href="https://i.stack.imgur.com/m876Z.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/m876Z.png" alt="enter image description here" /></a></p>
  <p>As you can see there are empty values from the other dropdown.</p>
  <p>How can i check the value for null or if its not empty.</p>