Topic ID as a variable?

Dev
14

What I ended up with is a more discreet showing of the topic ID. It’s still not searchable, but I’ll live with it until what I really need becomes a reality.

<script type="text/discourse-plugin" version="0.5">
api.decorateWidget('post-meta-data:after', dec => {
  if (dec.attrs.post_number === 1) {
    const topic = dec.getModel().get('topic');
    return dec.rawHtml(`<div class="post-info topic-id"><b>&nbsp#${topic.get('id')}</b></div>`);
  }
});
</script>

Problem is that this code is now outdated and I don’t know how to fix it.
What should it be updated to in order to be compliant?