toc.html

{{- /* Last modified: 2025-03-08T12:47:53-08:00 */}}

{{- /*
  Copyright 2023 Veriphor, LLC

  Licensed under the Apache License, Version 2.0 (the "License"); you may not
  use this file except in compliance with the License. You may obtain a copy of
  the License at

  https://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  License for the specific language governing permissions and limitations under
  the License.
*/}}

{{- /* Initialize. */}}
{{- $partialName := "toc-walk" }}

{{- /* Determine content path for warning and error messages. */}}
{{- $contentPath := "" }}
{{- with .File }}
  {{- $contentPath = .context.Path }}
{{- else }}
  {{- $contentPath = .context.Path }}
{{- end }}

{{- /* Check for duplicate heading IDs. */}}
{{- $duplicateIDs := slice }}
{{- range .context.Fragments.Identifiers }}
  {{- if gt ($.Fragments.Identifiers.Count .) 1 }}
    {{- $duplicateIDs = $duplicateIDs | append . }}
  {{- end }}
{{- end }}
{{- with $duplicateIDs | uniq }}
  {{- errorf "The %q partial detected duplicate heading IDs (%s) in %s" $partialName (delimit . ", ") $contentPath }}
{{- end }}

{{- /* Render. */}}
{{- if .context.Params.toc }}
  {{- with .context.Fragments.Headings }}
    {{- $startLevel := or ($.startLevel | int ) ($.context.Param "toc.startLevel" | int) 2 }}
    {{- $endLevel := or ($.endLevel | int ) ($.context.Param "toc.endLevel" | int) 3 }}
    {{- $numHeadings := where (sort $.context.Fragments.HeadingsMap) "Level" "in" (seq $startLevel $endLevel) | len }}
    {{- if ge $numHeadings (or ($.context.Param "toc.minNumHeadings" | int) 2) }}
      <nav class="o-aside__toc" aria-labelledby="toc">
        <ul>
          {{- $ctx := dict
            "page" $.context
            "contentPath" $contentPath
            "partialName" $partialName
            "startLevel" $startLevel
            "endLevel" $endLevel
            "headings" .
          }}
          {{- partial "inline/toc/walk" $ctx }}
        </ul>
      </nav>
    {{- end }}
  {{- end }}
{{- end }}

{{- /* Recursively walk the headings. */}}
{{- define "partials/inline/toc/walk.html" }}
  {{- $ctx := . }}
  {{- range $ctx.headings }}
    {{- if and (ge .Level $ctx.startLevel) (le .Level $ctx.endLevel) }}
      <li>
        {{- if not .ID }}
          {{- errorf "The %q partial detected that the %q heading has an empty ID attribute. See %s" $ctx.partialName .Title $ctx.contentPath }}
        {{- end }}
        {{- $href := printf "%s#%s" $ctx.page.RelPermalink .ID }}
        <a href="{{ $href }}" class="o-aside__toc-link"
          >{{ .Title | plainify | safeHTML }}</a
        >
        {{- with and (lt .Level $ctx.endLevel) .Headings }}
          <ul>
            {{- $ctx = merge $ctx (dict "headings" .) }}
            {{- partial "inline/toc/walk" $ctx }}
          </ul>
        {{- end }}
      </li>
    {{- else }}
      {{- $ctx = merge $ctx (dict "headings" .Headings) }}
      {{- partial "inline/toc/walk" $ctx }}
    {{- end }}
  {{- end }}
{{- end }}