Solving URL Parentheses Conflict in DecapCMS (formerly NetlifyCMS): A Guide for Text Fragment Highlighting

This guide, based on experiences using DecapCMS (formerly NetlifyCMS), provides a solution for handling URLs that include parentheses in Markdown, a common issue when using text fragment highlighting. Ensure your Markdown parser correctly interprets your URLs and your links work as expected.

Introduction

In the course of writing an article in Markdown on Github and building the site with Netlify using DecapCMS (formerly known as NetlifyCMS), a common problem was encountered. This problem is associated with a popular URL syntax for text fragment linking (also known as 'fragmention') which is often used for highlighting specific parts of webpages.

I.e., I wanted to instantly highlight the part of the text in a source, that the concept of “Sixteenth HD1080” is a computationally favorable: https://en.wikipedia.org/wiki/Sixteenth_HD1080#:~:text=HD1080%20is%201920x1080%20pixels%2C%20so,arithmetic%20shift%20right%204%20bits%29

The syntax is as follows: a URL followed by '#:~:text=' and then the specific text that you want to highlight. This can be quite useful when you want to point someone directly to a specific part of a webpage. For example:

https://en.wikipedia.org/wiki/Example_Page#:~:text=Example%20Text(Example)

Here, the text "Example Text(Example)" on the Wikipedia page "Example_Page" would be highlighted when the link is followed.

However, when using this syntax in Markdown documents, a problem arises. Markdown uses parentheses to define the start and end of a URL in link syntax, and the parentheses in the 'fragmention' syntax can interfere with this. This can lead to the Markdown parser interpreting the URL incorrectly, causing an error.

Let’s get into the solution for handling URLs with parentheses (especially text fragment links) in Markdown, ensuring that the Markdown parser correctly interprets the URL and the link works as expected when clicked.

Doc: Handling URLs with Parentheses in Markdown

When you are working with Markdown, there may be cases where you need to include a URL that contains parentheses. This can create issues because Markdown uses parentheses to define the start and end of a URL in link syntax. For example, a basic Markdown link is structured as follows:

[link text](URL)

However, if your URL also contains parentheses, the Markdown parser may get confused and interpret your URL incorrectly.

Consider the following example:

[link text](https://en.wikipedia.org/wiki/Example_Page#:~:text=Example%20Text(Example))

In this case, the Markdown parser may interpret the URL as ending at the first closing parenthesis, causing an error.

Solution

The solution to this problem is to percent-encode the parentheses within the URL. This involves replacing "(" with "%28" and ")" with "%29".

So, for the example above, the correct Markdown syntax would be:

[link text](https://en.wikipedia.org/wiki/Example_Page#:~:text=Example%20Text%28Example%29)

This will ensure that the Markdown parser correctly interprets the URL, and the link will still work correctly when clicked.

This is particularly useful when linking to a specific section of a webpage using the 'fragmention' syntax. For example, if you want to link to a specific section of a Wikipedia page and highlight some text, you might use a URL like the one in the example above. By percent-encoding the parentheses, you can avoid any issues especially with the less enhanced Markdown parser and ensure that your link works as expected.