hugo-theme-hilfe/layouts/shortcodes/mermaid.html

{{ if not (.Page.Scratch.Get "mermaid") }}
<!-- Include mermaid only first time -->
<script src="{{ "js/mermaid.min.js" | relURL }}"></script>
<script>
  mermaid.initialize({
    flowchart: { useMaxWidth: true }
  });
</script>
{{ .Page.Scratch.Set "mermaid" true }}
{{ end }}

<p class="mermaid{{ with .Get "class" }} {{ . }}{{ end }}">
  {{- .Inner -}}
</p>