How it was tested

remark-to-comark was run on the 100 most-starred GitHub repositories that declare a remark, rehype, unified, react-markdown, or MDX dependency, among them freeCodeCamp, n8n, Dify, Next.js, Supabase, and Storybook. Each run works on a copy of the project, with up to 300 Markdown files sampled from it.

On every project, the run checks that:

• check, rewrite, and content never throw.
• Rewritten code still parses and keeps its imports consistent, and a second run changes nothing.
• remark renders every escaped file byte for byte as before.
• Comark's HTML ends up no further from remark's than it was before the escapes.

Of 14,470 sampled documents that aren't MDX, 95.7% render the same HTML in Comark and in remark after migration, once whitespace is normalized. On the 31 projects whose remark plugins the test could load, it's 98.0%. No document broke the checks above. One project, MUI, ran past the test's 15-minute limit.

rewrite replaced 13 of the 161 unified chains it found, the other 148 having a reason to stay. Each of the 13 was rebuilt from its plugins and run against its replacement on that project's documents, and they match at 99.8 to 100%.

Most of what still differs are Comark bugs, 31 cases so far in comarkdown/comark#525, each with a minimal input and a playground link. comarkOptions() works around the ones it can, such as tight lists that keep a <p> and Markdown images that lose alt="".

Comark renders the same Markdown to HTML 6 to 7 times faster than remark. Each pipeline rendered every file 15 times on Node 24.21.0, taking turns, and the table shows the median pass:

remark is remark-parse, remark-gfm, remark-frontmatter, remark-rehype, and rehype-stringify. rehype-raw parses raw HTML the way comarkOptions() keeps it.

In the browser Comark costs more. Minified and gzipped, the Comark setup is 118 KiB, remark 48 KiB, and remark with rehype-raw 98 KiB. Most of the difference is js-yaml, because Comark parses frontmatter into an object where remark-frontmatter keeps the string.

To rerun them, install the repository with pnpm install --frozen-lockfile and run these from packages/remark-to-comark. The first times the remark, rehype, and unified READMEs installed at the repository root, the second this repository's Markdown, and the third measures the bundles.

node bench/render.mjs "node_modules/.pnpm/*/node_modules/{remark*,rehype*,unified*}/{readme,README}.md"
node bench/render.mjs
node bench/size.mjs

Timings depend on the machine, and the README count on the installed versions. Each run prints its file count and size.