Building a Powerful Markdown Processor for My Blog

When building a developer-focused blog, having a robust markdown processor isn’t just a nice to have, it’s essential. Markdown makes writing blog posts easy, and processing it effectively means presenting code snippets beautifully, clearly, and functionally.

In this post, I’ll explain step-by-step how I built a flexible and powerful markdown processing pipeline using unified, remark, rehype, and rehype-pretty-code to render visually appealing and interactive code blocks.

Why Markdown

Markdown is a lightweight markup language that’s easy to read and write. Developers commonly use it because:

• It’s simple, intuitive, and fast to write.
• It cleanly separates content from presentation.
• It integrates smoothly with static site generators and frameworks.

The Goal: Great Markdown Experience

I wanted my markdown processor to:

• Efficiently parse markdown to HTML.
• Display syntax-highlighted code snippets.
• Include an interactive copy button for code blocks.

Let’s dive into how I achieved this.

Step-by-Step Implementation

1. Reading the Markdown Files

The first step is straightforward: read the markdown file content from a directory.

const filePath = path.join(articlesDirectory, `${slug}.md`);
const fileContent = fs.readFileSync(filePath, "utf-8");

• articlesDirectory is the folder containing all your markdown files.
• slug is the unique identifier for each markdown file.

2. Parsing Frontmatter

Frontmatter provides metadata about the markdown post (e.g., title, description, tags). I use the popular library gray-matter:

const { content, data } = matter(fileContent);

• content contains the markdown body.
• data contains metadata like title, date, etc.

3. Markdown Processing Pipeline

Now, let’s convert markdown content into HTML. We’ll use a powerful combination of tools:

• unified: A toolchain for content transformation.
• remark: Parses markdown into a syntax tree (MDAST).
• rehype: Converts markdown syntax tree (MDAST) into an HTML syntax tree (HAST).
• rehype-pretty-code: Highlights code snippets beautifully.

Here’s the full implementation:

const htmlContent = await unified()
  .use(remarkParse)
  .use(remarkRehype)
  .use(rehypePrettyCode, {
    theme: "github-dark",
    transformers: [
      transformerCopyButton({
        visibility: "always",
        feedbackDuration: 3_000,
      }),
    ],
  })
  .use(rehypeStringify)
  .process(content);

4. Understanding the Processors

Let’s break down each step clearly:

• remarkParse: Converts markdown text into an abstract syntax tree (AST).
• remarkRehype: Transforms the markdown AST into an HTML-compatible syntax tree.
• rehypePrettyCode: Provides syntax highlighting for code blocks. I’m using the github-dark theme for clear visibility.
• transformerCopyButton: Adds a copy button to code blocks, improving user experience.
• rehypeStringify: Generates an HTML string from the processed syntax tree.

5. The Result

This implementation allows markdown files to render into clean, syntax-highlighted HTML effortlessly:

• ✅ Beautiful code syntax highlighting.
• ✅ Easy-to-use copy-to-clipboard functionality.
• ✅ Highly customizable themes and transformations.

Enhancements and Customizations

This solution is highly flexible. You can easily:

• Switch between multiple themes (dracula, nord, github-dark, etc.).
• Add other remark/rehype plugins to enrich your markdown experience (e.g., adding image optimizations, emoji support, or automatic link transformations).

Conclusion

Building a robust markdown processor significantly improves the readability and overall experience of your blog, especially for technical audiences. Using unified, remark, rehype, and rehype-pretty-code, you gain complete control over how your markdown content is presented, enhancing readability and interaction.