#access Astro.props in mdx?

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bronze jungle
# 
---
title: "Using MDX"
description: "Lorem ipsum dolor sit amet"
pubDate: "Jun 01 2024"
heroImage: "../../assets/blog-placeholder-5.jpg"
---

Some of my mdx content

{Astro.props.url}

import { type CollectionEntry, getCollection, render } from "astro:content";
import BlogPost from "../../layouts/BlogPost.astro";

export async function getStaticPaths() {
const posts = await getCollection("blog");
return posts.map((post) => ({
params: { slug: post.id },
props: post,
}));
}
type Props = CollectionEntry<"blog">;

const post = Astro.props;
const { Content } = await render(post);

<BlogPost {...post.data} slug={post.id}>
<Content />
</BlogPost>

south crestBOT
#

Hi @bronze jungle. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

#

You cannot directly access Astro.props inside an MDX file. The Astro.props object is available in Astro components and layouts, but not within the MDX content itself. In MDX, you can use frontmatter variables (like title, description, etc.) or exported variables, but you do not have access to the full Astro.props object as you would in an .astro file or a layout component.

If you need to use values from Astro.props in your MDX content, you should pass them as props to a layout or component that wraps your MDX content. For example, you can use a layout in your MDX frontmatter and then access Astro.props in that layout:

---
layout: ../../layouts/BlogPost.astro
title: "Using MDX"
description: "Lorem ipsum dolor sit amet"
pubDate: "Jun 01 2024"
heroImage: "../../assets/blog-placeholder-5.jpg"
---

Some of my mdx content

<!-- You cannot use {Astro.props.url} here -->

Then, in your layout (BlogPost.astro), you can access Astro.props:

---
// BlogPost.astro
const { title, url } = Astro.props;
---
<h1>{title}</h1>
<p>{url}</p>
<slot />

This way, any props you want to use in your MDX content must be passed through the layout, not accessed directly in the MDX file itself. For more details, see the section on Importing Layouts Manually (MDX) and Markdown Layout Props.

In summary:
You cannot use {Astro.props.url} directly in MDX content. Use a layout and access Astro.props there instead.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

@bronze jungle Kapa.ai is still learning and improving, please let me know how I did by reacting below.

bronze jungle
#

@south crest heres my blogpost.astro

import { Image } from "astro:assets";
import type { CollectionEntry } from "astro:content";
import BaseHead from "../components/BaseHead.astro";
import FormattedDate from "../components/FormattedDate.astro";
import Footer from "../features/footer/Footer.astro";
import Header from "../features/header/Header.astro";

type Props = CollectionEntry<"blog">["data"] & { slug?: string };

const { title, description, pubDate, updatedDate, heroImage, slug } =
Astro.props;

<html lang="en">
<head data-overlayscrollbars-initialize>
<BaseHead title={title} description={description} />
</head>

<body data-overlayscrollbars-initialize>
<Header />
<main>
<article>
<div class="hero-image">
{
heroImage && (
<Image
src={heroImage}
alt=""
transition:name={${slug} hero}
class="h-auto w-full"
/>
)
}
</div>
<div class="prose">
<div class="title">
<div class="date" transition:name={${slug} pubDate}>
<FormattedDate date={pubDate} />
{
updatedDate && (
<div class="last-updated-on">
Last updated on <FormattedDate date={updatedDate} />
</div>
)
}
</div>
<h1 transition:name={${slug} title}>{title}</h1>
<hr />
</div>
<slot />
</div>
</article>
</main>
<Footer />
</body>
</html>

which has slug available, how to pass to my actual mdx?

south crestBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

Based on the knowledge sources, you cannot pass additional props (like slug) directly from your Astro page to the MDX file and then access them inside the MDX content itself. MDX files do not have access to Astro.props or any props passed from the parent component/page. The only data available inside the MDX file are frontmatter variables and exported variables defined within the MDX file itself.

However, you can pass props (including slug) to your layout component (e.g., BlogPost.astro) when rendering the MDX content. The layout will receive these props via Astro.props, and you can use them there. The MDX content itself will be rendered inside the <slot /> of your layout, but it will not have access to those props.

Example usage:

Suppose you have a dynamic route that renders your MDX content and passes the slug:

---
// src/pages/blog/[slug].astro
import { getCollection, render } from "astro:content";
import BlogPost from "../../layouts/BlogPost.astro";

export async function getStaticPaths() {
  const posts = await getCollection("blog");
  return posts.map((post) => ({
    params: { slug: post.id },
    props: { ...post.data, slug: post.id }, // Pass slug here
  }));
}

const { Content } = await render(Astro.props);
---

<BlogPost {...Astro.props}>
  <Content />
</BlogPost>

Your BlogPost.astro layout (as you posted) will receive slug in Astro.props and can use it as needed.

But:
Inside your MDX file, you cannot access slug (or any other prop passed from the page/layout) directly. You can only use frontmatter variables or variables you export from the MDX file itself.

Summary:

  • Pass slug as a prop to your layout (BlogPost.astro), and use it there.
  • You cannot access slug inside the MDX content itself.
#

This is confirmed by the documentation:

To pass information to your MDX layout that does not (or cannot) exist in your frontmatter, you can instead import and use a <Layout /> component. This works like any other Astro component, and will not receive any props automatically. Pass it any necessary props directly... Then, your values are available to you through Astro.props in your layout, and your MDX content will be injected into the page where your <slot /> component is written.
Importing Layouts Manually (MDX)

If you need to use the slug inside the MDX content, you would need to add it to the frontmatter of the MDX file itself. Otherwise, keep all usage of slug in your layout or parent Astro components.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

@bronze jungle Kapa.ai is still learning and improving, please let me know how I did by reacting below.

bronze jungle
#

@south crest add the slug to mdx fontmatter

south crestBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

To add a slug to your MDX frontmatter, simply include it as a property at the top of your MDX file, just like any other frontmatter variable. Here’s how you do it:

---
title: "Using MDX"
description: "Lorem ipsum dolor sit amet"
pubDate: "Jun 01 2024"
heroImage: "../../assets/blog-placeholder-5.jpg"
slug: "using-mdx"
---

Some of my mdx content

Astro will use the slug you define in the frontmatter as the custom ID for this entry, which can affect the generated URL or how you query this content in your collection. This is the same approach as with Markdown files, and is documented in Defining custom IDs:

You can override an entry’s generated id by adding your own slug property to the file frontmatter...

---  
title: My Blog Post  
slug: my-custom-id/supports/slashes  
---  
Your blog post content here.

This works for both .md and .mdx files in Astro content collections.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

@bronze jungle Kapa.ai is still learning and improving, please let me know how I did by reacting below.

bronze jungle
#

@south crest yes but i want to render it in the mdx content as i want to pass it to an embedded component
Here is how you import and use a UI component inside of MDX.
When you open this page in the browser, you should see the clickable button below.

import HeaderLink from "../../components/navigation/header-link/HeaderLink.vue";

<HeaderLink href="#" onclick="alert('clicked!')" astroPathname={slug}>
Embedded component in MDX
</HeaderLink>

More Links

south crestBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

Based on the official Astro documentation, you cannot directly access props like slug (passed from a parent Astro page or layout) inside your MDX content. MDX files only have access to variables defined in their own frontmatter or exported within the MDX file itself. There is no supported way to inject additional props (such as slug from a dynamic route) into the MDX scope for use in embedded components within the MDX content itself.

If you want to use slug inside your MDX content (for example, to pass it to an embedded component), you must add it to the MDX frontmatter manually:

---
title: "Using MDX"
slug: "using-mdx"
---

import HeaderLink from "../../components/navigation/header-link/HeaderLink.vue";

<HeaderLink href="#" astroPathname={slug}>
  Embedded component in MDX
</HeaderLink>

This approach works because frontmatter variables are available in the MDX scope, but they must be defined in the file’s frontmatter. There is no documented way to pass dynamic props from the parent Astro page or layout into the MDX content for use in this way Importing Layouts Manually (MDX) MDX in Astro.

Summary:

  • You must define slug in the MDX frontmatter to use it in the MDX content.
  • You cannot pass slug from the parent Astro page/layout into the MDX content for use in embedded components.

If you need the slug to be dynamic, you would need to generate your MDX files with the correct frontmatter, or use a different approach (such as rendering the component in the layout and passing the prop there).

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:

#

@bronze jungle Kapa.ai is still learning and improving, please let me know how I did by reacting below.

bronze jungle
#

@south crest did not work says slug is undefined, heres my frontmatter in mdx

title: "Using MDX"
description: "Lorem ipsum dolor sit amet"
pubDate: "Jun 01 2024"
heroImage: "../../assets/blog-placeholder-5.jpg"
slug: "using-mdx"

south crestBOT
#

Let me check the knowledge base for you again. One moment! :books:

#

If you have defined slug in your MDX frontmatter as shown:

---
title: "Using MDX"
description: "Lorem ipsum dolor sit amet"
pubDate: "Jun 01 2024"
heroImage: "../../assets/blog-placeholder-5.jpg"
slug: "using-mdx"
---

You should be able to use {slug} in your MDX content, for example:

<HeaderLink href="#" astroPathname={slug}>
  Embedded component in MDX
</HeaderLink>

However, if you are seeing slug as undefined, there are a few possible reasons based on the knowledge sources:

  1. MDX Variable Scope:
    The Astro MDX integration supports using frontmatter variables in the MDX template. You should be able to reference them directly in your MDX content, as shown in the documentation:

    Add frontmatter properties just as you would in Markdown files, and these variables are available to use in the template, and as named properties when importing the file somewhere else.

    ---
title: 'My first MDX post'
author: 'Houston'
---
{frontmatter.title}
Written by: {frontmatter.author}

    MDX in Astro

    However, the example uses {frontmatter.title} rather than {title}. Try referencing your frontmatter variables as frontmatter.slug instead of just slug:

    <HeaderLink href="#" astroPathname={frontmatter.slug}>
  Embedded component in MDX
</HeaderLink>

  2. Exported Variables:
    If you want to use the variable directly (e.g., {slug}), you can also export it in your MDX file:

    export const slug = "using-mdx";

    Then, {slug} should be available in your MDX content.

#
  1. Component Import/Usage:
    Make sure your component is correctly imported and that you are not shadowing the variable name elsewhere in your MDX file.

Summary:

  • Try using {frontmatter.slug} in your MDX content.
  • Alternatively, export the variable: export const slug = "using-mdx"; and use {slug}.
  • If the issue persists, there may be a problem with how the MDX integration is configured or how the component is being used.

If after these changes slug is still undefined, the knowledge sources do not provide further troubleshooting steps for this specific issue.

Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: