Creating Anchor Links to Page Sections in MDX documents

Enhance navigation and make content more accessible by creating anchor links to specific sections within a page. This feature is particularly useful for long-form content, such as guides or documentation, where users can quickly jump to relevant sections without excessive scrolling.

In this article, we'll describe how we implemented anchor links in MDX documents and why we chose this approach over alternatives. If you're a developer working with MDX or similar technologies, this will give you insight into our solution and help you implement something similar in your own projects.

Table of Contents

• Introduction
• How We Create Anchor Links
  • Why We Use id Attributes in spans
• Scroll Margin for Fixed Navbar Support
• Alternatives We Considered
  • Auto-Generated IDs
  • Manual Heading IDs
  • JavaScript Scroll Management
• Why This Approach Works Best for MDXBlog
• Implementing This in Your MDX Project

Introduction

Anchor links are an excellent way to improve the usability of long-form content by allowing users to navigate directly to specific sections. In MDXBlog, we use a simple and effective approach to implement anchor links by utilizing id attributes on span elements.

How We Create Anchor Links

In MDXBlog, we use id attributes on headings and other section elements to enable anchor linking. These id attributes make it easy to link directly to specific sections of the document using anchor tags (#). Here's how it works:

Section:

mdxCopy
## <span id="getting-started">Getting Started</span>

In this example, the `<span>` tag has an `id` attribute of "getting-started". This ID allows us to create a link to this section by using an anchor tag elsewhere in the document:

Link to Section:

mdxCopy
[Getting Started](#getting-started)

When a user clicks on this link, they are automatically scrolled to the section with the corresponding id. This method is straightforward, semantic, and works out-of-the-box in any MDX document.

Why We Use id Attributes in spans

• Flexibility: By using span elements with id attributes, we can apply additional styles or classes to sections beyond what's available in markdown syntax.
• Control: We can fine-tune the layout of sections with more complex designs while still enabling anchor linking.
• SEO-Friendly: This method keeps the HTML output clean and ensures that the content structure remains clear for search engines.

Scroll Margin for Fixed Navbar Support

If you're using a fixed navbar at the top of your page, anchor links might cause the target section to scroll underneath the navbar, making it partially or completely hidden. To avoid this issue, we use the scroll-margin-top property in CSS to create an offset that ensures the target section remains visible.

Steps to Implement:

1. Add CSS to Adjust Scroll Behavior: In your global CSS file (e.g., globals.css), add the following rule to create a margin above any element with an id when it is scrolled into view:

   cssCopy
   [id] {
     scroll-margin-top: 80px; /* Adjust this value to match the height of your fixed navbar */
   }
   

   This property sets a margin of 80px at the top of each section, ensuring that when a section is scrolled into view via an anchor link, it doesn't get hidden beneath the navbar.

2. Why This Works:

   • When a user clicks an anchor link (e.g., [Jump to Custom Components](#custom-components)), the browser normally scrolls the target element to the very top of the page. If you have a fixed navbar, the top of the section can get obscured.
   • By adding scroll-margin-top, the browser leaves a gap above the section, effectively pushing the section down by the specified amount (80px in this case), so it remains fully visible.

This small tweak ensures a smooth navigation experience, especially for users of long-form content or documentation where anchor links are frequently used.

Alternatives We Considered

There are other methods we could have used for anchor linking in MDXBlog, but they didn’t fit our needs as well as the id attribute approach.

Auto-Generated IDs

• How it works: Some libraries automatically generate id attributes for headings (e.g., <h1>, <h2>, etc.) based on the heading text. This allows for linking without manually setting the id.
• Why we didn’t choose it: While auto-generated IDs reduce the need for manual id creation, they can be unpredictable if the heading text changes. Additionally, it’s harder to customize the exact format or style of the id attributes.

Manual Heading IDs

• How it works: In this method, we manually add id attributes to headings (<h2 id="section">Section Title</h2>).
• Why we didn’t choose it: While this is a straightforward approach, it limits our control over styling and customization. Using span tags with IDs instead allows for greater flexibility in organizing content and applying additional styles.

JavaScript Scroll Management

• How it works: This method involves using JavaScript to dynamically manage scrolling to different sections, typically using event listeners or smooth scrolling libraries.
• Why we didn’t choose it: Although this allows for smoother scroll transitions, it adds unnecessary complexity and JavaScript dependencies to the project. We wanted a simple, lightweight solution that relied purely on HTML and CSS.

Why This Approach Works Best for MDXBlog

• Simplicity: This solution uses plain HTML with no additional dependencies, making it lightweight and easy to implement.
• Maintainability: By keeping the solution simple and predictable, we can easily add, remove, or update anchor links without worrying about breaking the layout.
• Performance: This approach avoids the need for JavaScript, ensuring faster load times and better performance, especially on static sites.

Implementing This in Your MDX Project

To implement this anchor link method in your own MDX project, follow these steps:

1. Add id Attributes to Sections: Wherever you have a section that you want to link to, wrap the heading in a span tag with an id. For example:

   mdxCopy
   ## <span id="my-section">My Section</span>
   

2. Create Links to Sections: Link to sections by using the # symbol followed by the id value in your anchor tags:

   mdxCopy
   [Go to My Section](#my-section)
   

3. Add CSS for Fixed Navbar Support (Optional): If you have a fixed navbar, include the following CSS rule to ensure the sections are visible when scrolled into view:

   cssCopy
   [id] {
     scroll-margin-top: 80px;
   }
   

4. Optional Styling: If you want to style the sections differently, apply CSS classes to the span tags.

By following these steps, you'll be able to easily create anchor links in your MDX documents and ensure smooth navigation for users, even when using a fixed navbar.