@cocoa/eleventy-plugin-toc

[!NOTE] This repository is an updated fork of uncenter/eleventy-plugin-toc switching from a filter to a paired shortcode, and using @sindredorhus/slugify to guess at heading links if no IDs are present, for easier integration with Eleventy Id Attribute plugin. NB: This is a very brittle way to make a Table of Contents, and will break when you have repeated (sub)headings and if your slugify functions don't match perfectly.

[!IMPORTANT] This plugin is now ESM-only. It can be used in CJS though (i.e. imported via require) starting with Node.js version 20 and newer.

Easily generate a table of contents (TOC) for your Eleventy site, with easy configuration and customization.

HTML:

<h1>Hello, World</h1>
Lorem ipsum dolor sit amet, consectetur adipisicing elit.

<h2 id="greetings-from-mars">Greetings from Mars</h2>
Lorem ipsum dolor sit amet, consectetur adipisicing elit.

<h3>The red planet</h3>
Lorem ipsum dolor sit amet, consectetur adipisicing elit.

<h2 id="greetings-from-pluto">Greetings from Pluto</h2>

Generated TOC:

• Greetings from Mars
  • The red planet
• Greetings from Pluto

<nav class="toc">
  <ol>
    <li><a href="#greetings-from-mars">Greetings from Mars</a></li>
    <ol>
      <li><a href="#the-red-planet">The red planet</a></li>
    </ol>
    <li><a href="#greetings-from-pluto">Greetings from Pluto</a></li>
  </ol>
</nav>

Install

npm i @cocoa/eleventy-plugin-toc
pnpm add @cocoa/eleventy-plugin-toc
yarn add @cocoa/eleventy-plugin-toc
bun add @cocoa/eleventy-plugin-toc

Usage

Your heading elements will need to have id attributes on them, so that the table of contents can provide anchor links to them. Eleventy does not do this for you automatically, but you can use the provided Eleventy Id Attribute Plugin to add id attributes to the headings automatically.

[!IMPORTANT] Make sure not to duplicate the export default function (eleventyConfig) { line in your config file for any of the examples below! If you already have a export default function (eleventyConfig) { line, just add the lines above and below it to your config file.

In your Eleventy config file (.eleventy.js, eleventy.config.js, or eleventy.config.cjs), add your heading plugin of choice. This example uses the aforementioned IdAttributePlugin plugin:

import IdAttributePlugin from '@11ty/eleventy';
import slugify from '@sindresorhus/slugify';

export default function (eleventyConfig) {
  eleventyConfig.addPlugin(IdAttributePlugin, { slugify });
}

Then add the table of contents plugin:

import IdAttributePlugin from '@11ty/eleventy';
import pluginTOC from '@cocoa/eleventy-plugin-toc';
import slugify from '@sindresorhus/slugify';

export default function (eleventyConfig) {
  eleventyConfig.addPlugin(IdAttributePlugin, { slugify });
  eleventyConfig.addPlugin(pluginTOC, { slugify });
}

NOTE: We use plugin options to make sure both plugins use an identical slugify function, this works OK for most headings, but will break if a heading is repeated.

To use the table of contents in your templates, apply the toc shortcode to your template content:

[!IMPORTANT] The first matched heading on the page should be the topmost. Don't put an <h3> before an <h2>!

<aside>
  {% toc %}
    {{ content | safe }}
  {% endtoc %}
</aside>
<article>
  {{ content }}
</article>

Configuring

You can override some of the options at the time that you call it, or all of them when you add it in your Eleventy config. All of the options will be merged together, with the options passed to the filter taking precedence over the options passed to the plugin (which take precedence over the defaults).

Override the defaults for your whole site (defaults are shown):

{
    tags: ["h2", "h3", "h4"], // tags (heading levels) to include
    ignoredHeadings: ["[data-toc-exclude]"], // headings to ignore (list of selectors)
    ignoredElements: [], // elements (within the headings) to ignore when generating the TOC (list of selectors)
    ul: false, // whether to a use a `ul` or `ol`
    inheritAttributes: false, // whether to inherit heading attributes to TOC links
    wrapper: function (toc) {
        // wrapper around the generated TOC
        return `<nav class="toc">${toc}</nav>`;
    },
}

Or override as it's being invoked:

<aside>
  {% toc(tags=['h2', 'h3']) %}
    {{ content }}
  {% endtoc %}
</aside>

If you have specific headings which you don't want to be included in the TOC, you can add one of the ignoredHeadings selectors to exclude these headings (defaults to the[data-toc-exclude] selector).

Set inheritAttributes to true to copy heading attributes to TOC links, or provide an array of attribute names (e.g. ['data-value']) to copy only specific ones.

License

MIT