README

Generates a Table of Contents from H1...H6 Tags in HTML Content

NOTE: Version 4 of this library requires PHP 8.2 or newer.

• Version 3 is no longer maintained, but it supports PHP 7.2 - 8.1: composer require caseyamcl/toc ^3.0
• Version 2 is no longer maintained, but it supports PHP5 - 7.1: composer require caseyamcl/toc ^2.0

This package provides a simple, framework-agnostic library to build a Table-of-Contents from HTML markup. It does so by evaluating your H1...H6 tags. It can also automatically add appropriate id anchor attributes to header tags so that in-page links work.

Features:

• Generates HTML menus and KnpMenu Item menus
• Adds anchor ID attributes to H1...H6 tags in your content where they do not already exist
• You can specify which H1...H6 heading tag levels to include in the TOC
• Includes a Twig extension for generating TOCs and compatible markup directly in your templates
• Uses the flexible KnpMenu Library to generate menus
• PSR-12 compliant
• Unit-tested (95% coverage) and PHPStan Level 7 tested

In the spirit of KISS philosophy, this library makes a few assumptions:

1. The hierarchy of your content is defined solely by the header (H1...H6) tags. All other tags are ignored when generating the TOC.
2. The link titles in the Table of Contents match either the title attribute of the header tag, or if there is no title, the (slugged) plaintext body of the header tag.

Installation Options

Install via Composer by including the following in your composer.json file:

composer require caseyamcl/toc ^4.0

Or, drop the src folder into your application and use a PSR-4 autoloader to include the files.

Usage

This package contains two main classes:

1. TOC\MarkupFixer: Adds id anchor attributes to any H1...H6 tags that do not already have any (you can specify which header tag levels to use at runtime)
2. TOC\TocGenerator: Generates a Table of Contents from HTML markup

Basic Example:

$myHtmlContent = <<<END
    <h1>This is a header tag with no anchor id</h1>
    <p>Lorum ipsum doler sit amet</p>
    <h2 id='foo'>This is a header tag with an anchor id</h2>
    <p>Stuff here</p>
    <h3 id='bar'>This is a header tag with an anchor id</h3>
END;

$markupFixer  = new TOC\MarkupFixer();
$tocGenerator = new TOC\TocGenerator();

// This ensures that all header tags have `id` attributes so they can be used as anchor links
$htmlOut  = "<div class='content'>" . $markupFixer->fix($myHtmlContent) . "</div>";

// This generates the Table of Contents in HTML
$htmlOut .= "<div class='toc'>" . $tocGenerator->getHtmlMenu($htmlOut) . "</div>";

echo $htmlOut;

This produces the following output:

<div class='content'>
    <h1 id="this-is-a-header-tag-with-no-anchor-id">This is a header tag with no anchor id</h1>
    <p>Lorum ipsum doler sit amet</p>
    <h2 id="foo">This is a header tag with an anchor id</h2>
    <p>Stuff here</p>
    <h3 id="bar">This is a header tag with an anchor id</h3>
</div>
<div class='toc'>
    <ul>
        <li class="first last">
        <span></span>
            <ul class="menu_level_1">
                <li class="first last">
                    <a href="#foo">This is a header tag with an anchor id</a>
                    <ul class="menu_level_2">
                        <li class="first last">
                            <a href="#bar">This is a header tag with an anchor id</a>
                        </li>
                    </ul>
                </li>
            </ul>
        </li>
    </ul>
</div>

Twig Integration

This library includes a Twig extension that enables you to load TOC lists and add anchors to markup from your Twig templates.

To enable Twig integration, register the TocTwigExtension with your Twig environment:

use Twig\Environment;
use Twig\Loader\FilesystemLoader;

$myTwig = new Environment(new FilesystemLoader());
$myTwig->addExtension(new TOC\TocTwigExtension());

The extension adds a Twig function for generating an HTML Table of Contents:

{# Generates HTML markup for given htmlContent #}
<ul>{{ toc(htmlContent) }}</ul>

It also provides a function and a filter for ensuring that your content includes anchors for all HTML header tags.
They both do the same thing, so choose which one suits your needs best:

{# Adds anchor links (id tags) for given htmlContent #}
{{ add_anchors(htmlContent) }}

{# You can also use it as a filter #}
<div class='my_content'>
    {{ htmlContent | add_anchors }}
</div>

Your HTML content may be hard-coded in your Twig Template. An easy way to accommodate this is to make sure the content is surrounded by {% block %}...{% endblock %} tags, and then just pass in that block to the toc function.

For example:

{% extends 'base.html.twig' %}
{% block page_content %}
<div class='page_sidebar'>
   {{ toc(add_anchors(block('my_writeup'))) }}
</div>

<div class='page_content'>
   {{ add_anchors(block('my_writeup')) }}
</div>
{% endblock %}

{% block my_writeup %}
<h1>Hi There</h1>
<p>Lorum ipsum baz biz etecetra</p>
<h2>This is some content</h2>
<p>More content here.  Blah blah</p>
{% endblock %}

Specifying Heading Levels to Include

You can choose to include only specific h1...h6 heading levels in your TOC. To do this, pass two additional arguments to the TocGenerator::getHtmlMenu() method: $topLevel and $depth. For example:

$tocGenerator = new TOC\TocGenerator();
$someHtmlContent = '<div><h1>Test</h1><p>Lorum ipsum</p><h2>Test2</h2><p>Lorum ipsum</p></div>';

// Get TOC using h2, h3, h4
$tocGenerator->getHtmlMenu($someHtmlContent, 2, 3);

// Get TOC using h1, h2
$tocGenerator->getHtmlMenu($someHtmlContent, 1, 2);

// Get TOC using h4, h5, h6
$tocGenerator->getHtmlMenu($someHtmlContent, 4, 3);

Most other methods in the package handle these arguments as well:

$tocGenerator = new TOC\TocGenerator();
$markupFixer = new TOC\MarkupFixer();
$someHtmlContent = '<div><h1>Test</h1><p>Lorum ipsum</p><h2>Test2</h2><p>Lorum ipsum</p></div>';


// Get KnpMenu using h1, h2, h3
$tocGenerator->getMenu($someHtmlContent, 1, 3);

// Fix markup for h3, h4 tags only
$markupFixer->fix($someHtmlContent, 3, 2);

Twig functions and filters accept these arguments as well:

{# Generate TOC using h2, h3 tags #}
{{ toc(my_content, 2, 3) }}

{# Add anchors to h4, h5, h6 tags #}
{{ my_content | add_anchors(4, 3) }}

Customizing Menu Output

You can customize the rendering of lists that the TocGenerator class outputs. By default, TocGenerator uses the KnpMenu ListRenderer class to output the HTML.

You can pass your own instance of the ListRenderer class to TocGenerator::getHtmlMenu(). Or you can pass in your own renderer (implements Knp\Menu\Renderer\RendererInterface).

For example, you may wish to use different CSS classes for your list items:

$someHtmlContent = '<div><h1>Test</h1><p>Lorum ipsum</p><h2>Test2</h2><p>Lorum ipsum</p></div>';

$options = [
    'currentAsLink' => false,
    'currentClass'  => 'curr_page',
    'ancestorClass' => 'curr_ancestor',
    'branch_class'  => 'branch'
];

$renderer = new Knp\Menu\Renderer\ListRenderer(new Knp\Menu\Matcher\Matcher(), $options);

// Render the list
$tocGenerator = new TOC\TocGenerator();
$listHtml = $tocGenerator->getHtmlMenu($someHtmlContent, 1, 6, $renderer);

Customizing with Twig

The KnpMenu library offers more robust integration with the Twig Templating System than is offered by default with this library. You can take advantage of it by using the TwigRenderer that is bundled with KnpMenu:

use Knp\Menu\Matcher\Matcher;
use Knp\Menu\Renderer\TwigRenderer;
use Twig\Environment;
use Twig\Loader\FilesystemLoader;

$someHtmlContent = '<div><h1>Test</h1><p>Lorum ipsum</p><h2>Test2</h2><p>Lorum ipsum</p></div>';

$twigLoader = new FilesystemLoader(array(
    __DIR__.'/vendor/KnpMenu/src/Knp/Menu/Resources/views',
    // ...paths to your own Twig templates that render KnpMenus...
));

$twig = new Environment($twigLoader);
$itemMatcher = new Matcher();
$menuRenderer = new TwigRenderer($twig, 'knp_menu.html.twig', $itemMatcher);

$tocGenerator = new TOC\TocGenerator();

// Output the Menu using the template 
echo $menuRenderer->render($tocGenerator->getMenu($someHtmlContent));

Ordered vs Unordered Lists

The KnpMenu library produces unordered lists (ul) by default. This library includes a custom renderer for ordered lists:

$someHtmlContent = '<div><h1>Test</h1><p>Lorum ipsum</p><h2>Test2</h2><p>Lorum ipsum</p></div>';

// Ordered List
$orderedRenderedList = (new TOC\TocGenerator())->getOrderedHtmlMenu($someHtmlContent);

Twig Usage:

{# Generate ordered TOC #}
{{ toc_ordered(my_content) }}

{# The same options can be used for ordered lists as unordered lists #}
{{ toc_ordered(my_content, 1, 3) }}

Making ordered lists prettier using CSS

Below is some CSS to make your ordered lists look extra fancy (credit to @flaushi).

.toc ol {
  list-style-type: none;
  counter-reset: item;
  margin: 0;
  padding: 0;
}

.toc ol > li:before  {
  counter-increment: item;
  margin: 0;
  padding: 0;
  content: counters(item, ".") ". ";

Sample output:

1. Some heading
1.1 Some sub-heading
1.2 Another sub-heading
2. Another heading
2.0.1. Sub-sub-sub heading