title: Condition if else in pug
body: <p>I would like to make a simple condition in pug, which is :
  If this element exists > Show this element
  / Else > Show a text</p>
  
  <p>There is my code used :</p>
  
  <p>In app.js :</p>
  
  <pre><code>  axios
      .get(`${process.env.API_URL}/party/${req.params.id}`)
      .then(({ data }) =&gt; {
        let items = null;
        data.items.length === 0 ? items = false : items = true;
        res.render('party', { 
          party: data,
          title: data.name,
          items,
          url: `${process.env.FRONT_URL}:${process.env.PORT}/party/${data._id}` 
      })})
      .catch((err) =&gt; console.log(err))
    ;
  });
  </code></pre>
  
  <p>In my .pug file :</p>
  
  <pre><code>if items = false
    each item in party.items
      form(method="post" action=`/party/${party._id}/items/${item._id}`)
        p= `${item.name} - ${item.user}`
        button(type="submit") Supprimer
  else 
    p Il n'y a pas encore d'objet. Ajoutez-en un !
  </code></pre>
  
  <p>What should I write after my <code>if</code>?</p>