oxc-markdown-parser

oxc-markdown-parser parses CommonMark + GFM (and eventually MDX v3) into a span-faithful, style-preserving typed AST, designed for building formatters.

• Parse behavior targets micromark, the parser behind Prettier's markdown support (= CommonMark + GFM as GitHub renders it). Deliberate differences are listed in DIVERGENCES.md.
• Style facts (markers, fence chars, reference kinds, …) are first-class AST fields, so a printer never re-derives them by peeking at the source.
• Values are not cooked: consumers slice the original source through spans.
• MD and MDX are the same parser with construct toggles (Constructs); the API always returns (root, diagnostics), and diagnostics are structurally empty in MD mode.
• Prettier's extensions (math, liquid, wiki links) and ::: container directives are supported and enabled by default. Directive fence lines are kept verbatim, so the VitePress / markdown-it-container (::: tip Title) and Pandoc (::: {.class}) forms open one too.

Example

use oxc_markdown_parser::{Allocator, Parser};

let allocator = Allocator::default();
let parser = Parser::new(&allocator, "# Hello\n");
let ret = parser.parse();
println!("{:#?}", ret.root);
assert!(ret.diagnostics.is_empty());

More examples are available in examples.

Conformance

just conformance renders two suites to HTML and snapshots the results under tasks/conformance/snapshots:

• the CommonMark spec examples (spec.json),
• the GFM spec extension sections (spec.txt from cmark-gfm).

The pinned suite files are fetched on first run. All CommonMark examples pass; the remaining GFM differences are genuine micromark-vs-cmark-gfm disagreements, pinned in the snapshot.

Differential testing

just differential fuzzes the parser against mdast-util-from-markdown (micromark in Prettier's composition) and compares a structural signature of both trees. just fuzz-panic stresses byte/char boundaries; any panic fails.

Both need Node >= 22.18 and npm install in tasks/differential once.

License

MIT

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