title: Don't inject attribute with JQ if there was none
body: <pre><code>cat &quot;$FileName&quot; | jq --sort-keys 'map({&quot;author_id&quot;: .author.id,&quot;author&quot;: .author.name, &quot;badge&quot;: .author.badges[0].title, &quot;message&quot;, &quot;timestamp&quot;, &quot;time_in_seconds&quot;, &quot;time_text&quot;})' &gt; &quot;$TargetName&quot;
  </code></pre>
  <p>produces output with <code>&quot;time_in_seconds&quot;: null</code> if there was no <code>&quot;time_in_seconds&quot;</code> in source JSON. How to eliminate this:</p>
  <ul>
  <li>for this very attribute?</li>
  <li>for all attributes?</li>
  </ul>