markdownblog/posts/scrollingheading.md

✅ Refactor Plan for Markdown Anchor Linking

🧠 1. Understand the Problem

link links rely on corresponding HTML elements having id="heading".

marked.js by default doesn’t add id attributes to headings unless configured.

Your headings might be missing ids or may not match the expected format (e.g., space vs. hyphen mismatch).

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🧱 2. Refactor Outline

🔧 Step 1: Customize Marked Renderer

Use a custom Renderer in marked.js to automatically generate slugified ids for headings:

import { marked } from "marked"; import slugify from "slugify";

const renderer = new marked.Renderer();

renderer.heading = (text, level) => { const slug = slugify(text, { lower: true, strict: true }); return <h${level} id="${slug}">${text}</h${level}>; };

marked.setOptions({ renderer });

> ✅ You can use slugify or write your own slug generator if needed.




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🧩 Step 2: Normalize Anchor Links in Markdown

Ensure links like [My Paragraph](#my-paragraph) are slugified the same way as the ids:

Ensure slugify rules match exactly with those used in the heading renderer.

If links are auto-generated or user-written, you may want to validate or transform them in your rendering pipeline.



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🧪 Step 3: Test Scroll Behavior

If scrolling doesn't work as expected, make sure your links are:

Properly rendered as <a href="#some-id">...</a>

The target heading exists in the DOM at time of click (no lazy-loading issues).


Check for any custom scroll behavior in your layout that may interfere (e.g., smooth scroll or offset handling for sticky headers).



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💡 Optional Improvements

➕ Add Smooth Scrolling

In _app.tsx or layout file:

html {
  scroll-behavior: smooth;
  }

  🛑 Handle Scroll Offset (if using fixed/sticky headers)

  Add a little scroll offset with a custom scroll handler:

  useEffect(() => {
    const handler = (e: any) => {
        if (e.target.hash) {
              e.preventDefault();
                    const id = e.target.hash.slice(1);
                          const element = document.getElementById(id);
                                if (element) {
                                        const yOffset = -80; // adjust if you have a sticky header
                                                const y = element.getBoundingClientRect().top + window.pageYOffset + yOffset;
                                                        window.scrollTo({ top: y, behavior: 'smooth' });
                                                              }
                                                                  }
                                                                    };

                                                                      document.querySelectorAll('a[href^="#"]').forEach((el) =>
                                                                          el.addEventListener('click', handler)
                                                                            );

                                                                              return () => {
                                                                                  document.querySelectorAll('a[href^="#"]').forEach((el) =>
                                                                                        el.removeEventListener('click', handler)
                                                                                            );
                                                                                              };
                                                                                              }, []);


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                                                                                              📁 3. Folder/File Structure (Suggested)

                                                                                              /lib
                                                                                                markdown.ts         # marked.js config and renderer
                                                                                                /pages
                                                                                                  /blog/[slug].tsx    # uses markdown.ts to render content


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                                                                                                  ✅ Summary Checklist

                                                                                                  Step	Task	Status

                                                                                                  1	Add custom heading renderer in marked.js	⬜
                                                                                                  2	Ensure consistent slugification	⬜
                                                                                                  3	Fix anchor tag rendering in links	⬜
                                                                                                  4	Add smooth scrolling / offset scroll fix	⬜
                                                                                                  5	Test across multiple headings & links	⬜



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