Recursively list out sections and pages for a nice hugo navigation for a section or site

example-template-usage.html

{{ define "main" }}
<div id="wrapper">
  <div id="sidebar">
    {{ partial "sidebar-sections-list.html" .Site.Sections }}
  </div>
  <div id="content">
    <!-- ... -->
  </div>
</div>
{{end}}

recursive-section-page-list-partial.html

{{ if gt (len .) 0 }}
  <ol class="list list-section">
    {{ range sort $section_pages "File.Path" }}
      <li class="list-section-page">
        <a href="{{ .Permalink }}">{{ .Title }}</a>
        {{ partial "sidebar-sections-list.html" (union .Pages .Sections) }}
      </li>
    {{ end }}
  </ol>
{{ end }}

I did not know about len ., thanks. I was able to solve a totally different problem by trying out your code and using that 👍