A long page with many headings can benefit from a table of contents.

headings.md

# Section 1

Introduction for section 1…

## Section 1.1

Text of section 1.1…

## Section 1.2

Text of section 1.2…

# Section 2

## Section 2.1

Introduction for section 2.1…

### Section 2.1.1

Text of section 2.1.1…

Origami’s markdown outline function regroups markdown content into an object reflecting the document’s heading structure.

$ ori Origami.mdOutline headings.md
Section 1:
  _text: Introduction for section 1…
  Section 1.1: Text of section 1.1…
  Section 1.2: Text of section 1.2…
Section 2:
  Section 2.1:
    _text: Introduction for section 2.1…
    Section 2.1.1: Text of section 2.1.1…
$

Use a template to turn that structure into links!

headings.ori

// Given an outline, return navigation links. If a given heading has
// subheadings, this template calls itself recursively.
(outline) => Tree.indent`
  <ul>
    ${ Tree.map(outline, (content, heading) =>
      heading === "_text"
        ? ""
        : Tree.indent`
          <li>
            <a href="#${ Origami.slug(heading) }">${ heading }</a>
          </li>
          ${ Tree.isMaplike(content) ? headings.ori(content) : "" }
        `
    ) }
  </ul>
`