recma-mdx-change-props

Warning

The recma-mdx-change-props is useful for next-mdx-remote or next-mdx-remote-client users in nextjs applications.

This package is a unified (recma) plugin that enables the use of expressions like {props.foo} in MDX documents.

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?

Use this plugin to enable expressions like {props.foo} in MDX documents.

This plugin allows you to pass the props object in the scope variable when using next-mdx-remote or next-mdx-remote-client.

const scope = {
  props: {
    foo: "foofoo",
    baz: "bazbaz"
  }
}

<MDXRemote scope={scope} /* ... */ />

The recma-mdx-change-props changes the props parameter into _props in the function _createMdxContent in the compiled source; and makes appropriate changes in order to do so. Without recma-mdx-change-props, there will be a confliction caused by "props" in the function _createMdxContent(props){} and the expression like {props.foo} in a MDX document will not work.

Installation

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

npm install recma-mdx-change-props

or

yarn add recma-mdx-change-props

Usage

Say we have the following file, example.mdx,

# Hi {props.foo}
      
<Test name={props.baz} />

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

import { read } from "to-vfile";
import { compile } from "@mdx-js/mdx";
import recmaMdxChangeProps from "recma-mdx-change-props";

main();

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

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

  return String(compiledSource);
}

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

function _createMdxContent(_props) {
  const _components = {
    h1: "h1",
    ..._props.components
  }, {Test} = _components;
  // ...
  return _jsxs(_Fragment, {
    children: [_jsxs(_components.h1, {
      children: ["Hi ", props.foo]
    }), "\\n", _jsx(Test, {
      name: props.baz
    })]
  });
}

And, this provides us to pass an object containing the props key during function construction of the compiled source.

const scope = {
  title: "My Article",
  props: {
    foo: "foofoo",
    bar: "barbar",
  }
}

Without the recma-mdx-change-props, the statements props.foo and props.baz will be undefined during function construction.

function _createMdxContent(props) {
  const _components = {
    h1: "h1",
    ...props.components
  }, {Test} = _components;
  // ...
  return _jsxs(_Fragment, {
    children: [_jsxs(_components.h1, {
      children: ["Hi ", props.foo]
    }), "\\n", _jsx(Test, {
      name: props.baz
    })]
  });
}

Options

All options are optional, and implemented as for being more flexible in case of need to change the names.

export type ChangePropsOptions = {
  funcName?: string; // default is "_createMdxContent" which the plugin looks for
  propName?: string; // default is "props" which the plugin looks for
  propAs?: string; // default is "_props" which the plugin converts into
};

The options are self-explainotary, so that is why no need to represent more example here.

use(recmaMdxChangeProps, {propAs: "__props__"} as ChangePropsOptions);

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 ChangePropsOptions.

Compatibility

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

Security

Use of recma-mdx-change-props 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

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.

License

MIT License © ipikuka