Gatsby 3 Scroll to Anchor in your MDX Blog Posts # Gatsby 3 Scroll to Anchor in your MDX Blog Posts #

⚓️ Why use Scroll to Anchor in your Gatsby MDX Blog? #

It is nothing more complicated than this; scroll to anchor improves the user experience for your blog post readers. Your posts become more shareable as soon as you add the anchors. What's more, it's not complicated to implement.

We will only go so far as implementing the basics here. We then make sure the result is accessible. Of course, you can add more features, use Gatsby plugins or create your own with smooth scroll and the like. See Scott Spence's recent webcast  on how to create a Gatsby plugin for Scroll to Anchor with bells and whistles. However, if you are looking for a quick solution to fill a 10‑minute empty window in your day, jump to the following paragraph where we code it up.

🧱 Gatsby 3 Scroll to Anchor Implementation #

Climate Gatsby 3 MDX Blog Starter #

To speed things up, we’ll use a Gatsby 3 MDX Blog starter  . To begin, clone the repo from GitHub and fire up Gatsby:

    
gatsby new my-mdx-blog-starter https://github.com/rodneylab/gatsby-starter-climate
cd my-mdx-blog-starter
cp .env.EXAMPLE .env.development
cp .env.EXAMPLE .env.production
gatsby develop

  

Have a quick look through the folders just to get used to the setup. Once you have a feel for it, we'll carry on. There are a few blog posts written in MDX already in the content/blog folder. Let's look at the folding-camera post. Open up the file content/blog/folding-camera/index.mdx in VS Code or whichever text editor you prefer. The top part of the file contains front matter. This is nothing more than metadata on the post which can be used for Search Engine Optimization (SEO) among other things. Following on, you will come to the line below:

    
16 ## What is a Folding Camera?
17  
18 Folding cameras are a well kept secret.  Typically, ...

  

The top line here is an h2 heading. This will be our first candidate for adding an anchor link to. Now we know we will be doing, let's roll our sleeves up and get to it!

Heading React Component #

A fantastic feature of MDX is the ability to use “shortcodes” in our mark-up. These are nothing more than React components. That's exactly what we will use here. We will create a React component to show the link shortcut. Create a Heading.jsx file in the src/components folder and add the following code to it:

    
1 import React from 'react';
2 import PropTypes from 'prop-types';
3    
4 const Heading = ({ 'aria-label': ariaLabel, children, as, hash }) => {
5   if (hash === '') {
6     return React.createElement(as, [], { children });
7   }
8   return React.createElement(
9     as,
10     {
11       id: hash,
12     },
13     <span>
14       {children}
15       {' '}
16       <a aria-describedby={hash} aria-label={ariaLabel} href={`A;#${hash}`A;}>
17         #
18       </a>
19     </span>,
20   );
21 };
22   
23 Heading.defaultProps = {
24   as: 'h1',
25   hash: '',
26 };
27   
28 Heading.propTypes = {
29   'aria-label': PropTypes.string.isRequired,
30   children: PropTypes.oneOfType([PropTypes.arrayOf(PropTypes.node), PropTypes.node]).isRequired,
31   as: PropTypes.oneOf(['h1', 'h2', 'h3', 'h4', 'h5', 'h6']),
32   hash: PropTypes.string,
33 };
34   
35 export { Heading as default };

  

Here we will pass in a child element which will, eventually, be the text of our heading. We will get a React element to be rendered out of the component. We can specify the level of heading (h1, h2, etc.) in the as field passed in to the component. Note that after the heading, we have an anchor element which contains the link. As it stands, this will be displayed all the time, instead of only showing as the mouse hovers over the title. We will fix that later.

To make the link more accessible, we have included an aria-describedby attribute. The id it mentions will be attached to the React element we are creating.

Render our New Component #

In order to render our link, we need to include it as a shortcode in our template. To do that end, we need to import the new component into the template used for blog posts. This is in the file src/components/PureBlogPost.jsx:

    
7 import { ExternalLink, TwitterMessageLink } from './Link';
8 import Heading from './Heading';
9 import { PureLayout as Layout } from './Layout';
10 import { PureSEO as SEO } from './SEO';

  

Now we have the component imported, we want to include in the shortcodes which the template provides edit the file to match this:

    
12 const shortcodes = {
13   ExternalLink,
14   Heading,
15   Link,
16   TwitterMessageLink,
17 };

  

The MDXProvider component will now recognize the Header component in our MDX file and render the Header React component.

Now that the component is included in the template, the next step is to use the new component in the markdown. Let's go back to content/blog/folding-camera/index.mdx and add the component for the first heading:

    
16 <Heading aria-label="Jump to section: What is a Medium Format Camera?" as="h2" hash="whatIsAMediumFormatCamera">What is a Medium Format Camera?</Heading>
17  
18 Folding cameras are a well kept secret.  Typically, ..

  

Note the change in syntax because we now want to render a React component. Refresh your browser, and you will finally see the link appear after the heading. Also, click it and the heading should scroll to the top of the page.

Finish Up #

So far so good, but we're not done yet! Let's finish off. We want to hide the link, while the mouse pointer isn't hovering over it. To this end, we are going to use React hooks. Specifically, we will use the useState hook. Let's go back to src/components/Heading.jsx and edit the file to match this:

    
1 import React, { useState } from 'react';
2 import PropTypes from 'prop-types';
3   
4 const Heading = ({ 'aria-label': ariaLabel, children, as, hash }) => {
5   const [showLink, setShowLink] = useState(false);
6   
7   if (hash === '') {
8     return React.createElement(as, [], { children });
9   }
10   return React.createElement(
11     as,
12     {
13       id: hash,
14       onMouseEnter: () => setShowLink(true),
15       onMouseLeave: () => setShowLink(false),
16     },
17     <span>
18       {children}
19       {' '}
20       <a aria-describedby={hash} aria-label={ariaLabel} href={`A;#${hash}`A;}>
21         #
22       </a>
23     </span>,
24   );
25 };
26   
27 Heading.defaultProps = {
28   as: 'h1',
29   hash: '',
30 };
31   
32 Heading.propTypes = {
33   'aria-label': PropTypes.string.isRequired,
34   children: PropTypes.oneOfType([PropTypes.arrayOf(PropTypes.node), PropTypes.node]).isRequired,
35   as: PropTypes.oneOf(['h1', 'h2', 'h3', 'h4', 'h5', 'h6']),
36   hash: PropTypes.string,
37 };
38   
39 export { Heading as default };

  

Here we have created a showLink variable which is tracked with useState. While the mouse hovers over the link, showLink is set to true. Similarly, when the mouse leaves the area, it is set back to false. We are missing one thing now. You will notice the anchor link is still always displayed. We need to add some styling and logic to hide it based on the value of showLink.

Let's create the style first. Create a file at src/components/Heading.module.scss:

    
1 .hide-heading-link-visually {
2   border: 0;
3   clip: rect(1px, 1px, 1px, 1px);
4   clip-path: inset(50%);
5   height: 1px;
6   margin: -1px;
7   width: 1px;
8   overflow: hidden;
9   position: absolute !important;
10   word-wrap: normal !important;
11 }

  

The last step is to import this style module and add a class to the anchor:

    
1 import React, { useState } from 'react';
2 import PropTypes from 'prop-types';
3 import { hideHeadingLinkVisually } from './Heading.module.scss';
4     // TRUNCATED...
5     <span>
6       {children}
7       {' '}
8       <a aria-describedby={hash} aria-label={ariaLabel} className={showLink ? '' : hideHeadingLinkVisually} href={`A;#${hash}`A;}>
9         #
10       </a>
11     </span>,
12     // TRUNCATED...

  

Basically what we are doing here is ensuring the anchor link will be announced by screen readers even when it is hidden visually. It is visually hidden whenever the mouse pointer is outside the title area.

That's it! You can go through and change the other headings to give them anchor links too.

🙏🏽 Gatsby 3 Scroll to Anchor: Feedback #

Have you found this post useful? I rather do hope it was easy enough to follow. Please let me know in any case. I would love to know your thoughts on the starter. Did it save you a bit of time by not having, firstly, to code a whole website from scratch to try out this code? Was it easy to download and start with Gatsby 3? Also get in touch if you want to see other posts in this area. If you have found this post useful and can afford even a small contribution, please consider supporting me through Buy me a Coffee.

Finally, feel free to share the post on your social media accounts for all your followers who will find it useful. You can get in touch via @askRodney on Twitter and also askRodney on Telegram  . Also, see further ways to get in touch with Rodney Lab. We post regularly on online privacy and security, as well as Gatsby 3. Also, subscribe to the newsletter to keep up-to-date with our latest projects.