# Table of Contents
Navigate the hierarchy of headings for the current page.
```html
---
interface PageHeadings {
/** The text value within the heading tag; stripped of HTML. */
text: string;
/** A generated slug value based on the text. */
slug: string;
/** Depth indicates headings H1-H6. */
depth: number;
}
/** The generated list of page headings, slugs, and depth. */
const headings: PageHeadings[] = [
{ text: 'Real World Example', slug: 'real-world-example', depth: 1 },
{ text: 'Semantic Markup', slug: 'semantic-markup', depth: 1 },
{ text: 'Utilities', slug: 'utilities', depth: 1 },
{ text: 'Grid', slug: 'grid', depth: 2 },
{ text: 'Alignment', slug: 'alignment', depth: 2 },
{ text: 'Responsive Design', slug: 'responsive-design', depth: 2 },
{ text: 'In Conclusion', slug: 'in-conclusion', depth: 1 },
];
/** Provide a padding-left class based on the depth. */
function setIndentationClass(depth: number) {
// prettier-ignore
switch(depth) {
case(6): { return 'pl-12';
}
case(5): { return 'pl-10';
}
case(4): { return 'pl-8';
}
case(3): { return 'pl-6';
}
case(2): { return 'pl-4';
}
case(1): { return 'pl-2';
}
default: { return 'pl-0';
}
}
}
---
```
## Deep Linking
Browsers allow you to deep link to any element via the ID. This is accomplished with an anchor tag and hashed (`#`) href value. When interacting with these anchors, the viewport will automatically attempt to scroll the `` element and bring the element into view.
```html
Some Example Heading
```
```html
Some Example Heading
```
> TIP: If you abstract scrolling away from the `` element, this will not work.
## Scroll Behavior
You may optionally choose to implement a smooth [scroll behavior](https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-behavior) using CSS.
```html
```
```css
body {
scroll-behavior: smooth;
}
```
## Generate a Slug
The following provides a barebones implementation for generating a slug based on a heading text value.
```ts
function generateSlug(text: string, prefix?: string = '', suffix?: string = '') {
// Format the slug from the text value.
const slug = text
.toLowerCase()
.replaceAll(/[^a-zA-Z0-9 ]/g, '')
.replaceAll(' ', '-')
.toLowerCase();
// Note that you can optionally apply a prefix/suffix.
return `${prefix}${slug}${suffix}`;
}
// Usage
generateSlug('An Example Header'); // result: an-example-header
generateSlug('An Example Header', 'skeleton-'); // result: skeleton-an-example-header
generateSlug('An Example Header', '', '-skeleton'); // result: an-example-header-skeleton
```
## Guides
Specific instructions for generating headings will differ based on your meta-framework and your application architecture. Below are a few suggestions, but this is neither a definitive or exhaustive list of all available options.
- [Astro](https://kld.dev/building-table-of-contents/) - enables you to automatically generate headings using built-in MDX features.
- [Svelte](https://www.melt-ui.com/docs/builders/table-of-contents) - Melt UI provides a headless component solution for Svelte.
- [Next.js](https://nextra.site/docs/docs-theme/theme-configuration#toc-sidebar) - Nextra provides a headless component solution for Next.js + MDX.
- [Rehype Plugin](https://github.com/stefanprobst/rehype-extract-toc) - a general purpose Rehype plugin for generating a table of contents.