mdx2vast

mdx2vast is a CLI tool that converts MDX files to HTML while preserving JSX syntax and components. This format (HTML that retains the structure of the original file) is used by Vale to provide markup-aware linting.

Installation

Ensure you have Node.js installed on your system.

Install via npm:

npm install -g mdx2vast

Usage

Run the CLI tool with the following command:

mdx2vast input.mdx

It also reads a single document from standard input:

mdx2vast < input.mdx

Batch mode

Starting the process costs about 160 ms, nearly all of it importing the MDX toolchain, against roughly 4 ms to convert an average document. A caller with thousands of files spends most of its time on imports it has already done.

--batch reads documents until standard input closes and answers each one, so that cost is paid once. On a 7,500-file corpus this is the difference between about fifteen minutes and about thirty seconds.

mdx2vast --batch < frames

Documents are length-prefixed rather than delimited, because MDX may contain any byte sequence a delimiter could use:

request   <byteLength> LF <bytes>
response  "ok " <byteLength> LF <bytes>
          "err " <byteLength> LF <message>

Lengths count bytes rather than characters, so multi-byte content frames correctly. A document that fails to convert answers err and the run continues; one unparseable file does not end the batch.

Output is identical to single-document mode — the test suite asserts this per fixture.