recma-mdx-import-media

This package is a unified (recma) plugin that turns media relative paths into import declarations for both markdown and html syntax in MDX

unified is a project that transforms content with abstract syntax trees (ASTs) using the new parser micromark. recma adds support for producing a javascript code by transforming esast which stands for Ecma Script Abstract Syntax Tree (AST) that is used in production of compiled source for the MDX.

When should I use this?

If you're working with MDX and want to include media/asset with relative path using markdown syntax, without providing an import statement, such as:

![alt](./image.png)

![alt](../blog-assets/image.png)

If you're working with MDX and want to include media/asset with relative path using html syntax, without providing an import statement, such as:

<img src="./image.png" alt="alt" />

<img src="../blog-assets/image.png" alt="alt" />

Because, recma-mdx-import-media creates import statements and assign the identifier into proper element in the compiled source.

recma-mdx-import-media only processes relative paths (starts with ./ or ../ or direct file name); leaving protocol-like patterns (like http://), root-relative URLs (like /pathname), and absolute paths (file:///) unchanged.

You might run into issues because bundlers like Webpack and Vite don't natively recognize these references (.png, .jpeg etc.)—they only handle imports. recma-mdx-import-media bridges that gap by converting media relative references into import declarations in compiled MDX source, ensuring bundlers can process them correctly, for both markdown and HTML syntax.

The list of the tags and attributes that recma-mdx-import-media process

• img --> src, srcset,
• video --> src, poster,
• audio --> src,
• source --> src, srcset,
• embed --> src,
• track --> src,
• input[type="image"] --> src,
• script --> src

recma-mdx-import-media supports the meta information (#hash and ?querystring) on the asset path.

During process, the meta information in the relative path is stripped out in the import statement.

In order you process the meta information for further process, it is added as a property into the asset as data-meta for src and poster attributes. but it preserved in srcset instead of passing it to data-meta.

Installation

This package is suitable for ESM only. In Node.js (version 18+), install with npm:

npm install recma-mdx-import-media

or

yarn add recma-mdx-import-media

Usage

Say we have the following file, example.mdx,

![alt](./image.png)

<img src="../../image.png" alt="alt" />

And our module, example.js, looks as follows:

import { read } from "to-vfile";
import { compile } from "@mdx-js/mdx";
import recmaMdxImportMedia from "recma-mdx-import-media";

main();

async function main() {
  const source = await read("example.mdx");

  const compiledSource = await compile(source, {
    recmaPlugins: [recmaMdxImportMedia],
  });

  return String(compiledSource);
}

Now, running node example.js produces the compiled source like below:

// ...
+ import imagepng$recmamdximport from "./image.png";
+ import imagepng_1$recmamdximport from "../../image.png";
function _createMdxContent(props) {
  const _components = {
    img: "img",
    p: "p",
    ...props.components
  };
  return _jsxs(_Fragment, {
    children: [_jsx(_components.p, {
      children: _jsx(_components.img, {
-        src: "./image.png",
+        src: imagepng$recmamdximport,
        alt: "alt"
      })
    }), "\\n", _jsx("img", {
-      src: "../../image.png",
+      src: imagepng_1$recmamdximport,
      alt: "alt"
    })]
  });
}
// ...

This is roughly equivalent with:

import imagepng$recmamdximport from "./image.png";
import imagepng_1$recmamdximport from "../../image.png";

export default function MDXContent() {
  return (
    <p>
      <img alt="alt" src={imagepng$recmamdximport} />
      <img alt="alt" src={imagepng_1$recmamdximport} />
    </p>
  )
}

If you want to resolve the relative paths (starts with ./ or ../) of the assets for further process, you are recommended to use recma-mdx-change-imports.

Options

All options are optional and have default values.

export type ImportMediaOptions = {
  excludeSyntax?: Array<"markdown" | "html">; // default is empty array []
};

excludeSyntax

It is an array option to exlude markdown or html syntax or both. The option are self-explainotary.

use(recmaMdxImportMedia, { excludeSyntax: ["html"] } as ImportMediaOptions);

Now, <img /> like html syntax will be excluded.

use(recmaMdxImportMedia, { excludeSyntax: ["markdown"] } as ImportMediaOptions);

Now, ![]()) like markdown syntax will be excluded.

use(recmaMdxImportMedia, { excludeSyntax: ["html", "markdown"] } as ImportMediaOptions);

Now, both html and markdown syntax will be excluded. The plugin becomes effectless.

Syntax tree

This plugin only modifies the ESAST (Ecma Script Abstract Syntax Tree) as explained.

Types

This package is fully typed with TypeScript. The plugin options is exported as ImportMediaOptions.

Compatibility

This plugin works with unified version 6+. It is compatible with mdx version 3+.

Security

Use of recma-mdx-import-media does not involve user content so there are no openings for cross-site scripting (XSS) attacks.

My Plugins

I like to contribute the Unified / Remark / MDX ecosystem, so I recommend you to have a look my plugins.

My Remark Plugins

• remark-flexible-code-titles – Remark plugin to add titles or/and containers for the code blocks with customizable properties
• remark-flexible-containers – Remark plugin to add custom containers with customizable properties in markdown
• remark-ins – Remark plugin to add ins element in markdown
• remark-flexible-paragraphs – Remark plugin to add custom paragraphs with customizable properties in markdown
• remark-flexible-markers – Remark plugin to add custom mark element with customizable properties in markdown
• remark-flexible-toc – Remark plugin to expose the table of contents via vfile.data or via an option reference
• remark-mdx-remove-esm – Remark plugin to remove import and/or export statements (mdxjsEsm)

My Rehype Plugins

• rehype-pre-language – Rehype plugin to add language information as a property to pre element
• rehype-highlight-code-lines – Rehype plugin to add line numbers to code blocks and allow highlighting of desired code lines
• rehype-code-meta – Rehype plugin to copy code.data.meta to code.properties.metastring

My Recma Plugins

• recma-mdx-escape-missing-components – Recma plugin to set the default value () => null for the Components in MDX in case of missing or not provided so as not to throw an error
• recma-mdx-change-props – Recma plugin to change the props parameter into the _props in the function _createMdxContent(props) {/* */} in the compiled source in order to be able to use {props.foo} like expressions. It is useful for the next-mdx-remote or next-mdx-remote-client users in nextjs applications.
• recma-mdx-change-imports – Recma plugin to convert import declarations for assets and media with relative links into variable declarations with string URLs, enabling direct asset URL resolution in compiled MDX.
• recma-mdx-import-media – Recma plugin to turn media relative paths into import declarations for both markdown and html syntax in MDX.
• recma-mdx-import-react – Recma plugin to ensure getting React instance from the arguments and to make the runtime props {React, jsx, jsxs, jsxDev, Fragment} is available in the dynamically imported components in the compiled source of MDX.

License

MIT License © ipikuka