ironmark

Fast Markdown to HTML/AST parser written in Rust with zero third-party parsing dependencies. Fully compliant with CommonMark 0.31.2 (652/652 spec tests pass). Available as a Rust crate and as an npm package via WebAssembly, with both HTML and AST output APIs.

Options

All options default to true.

Option	JS (camelCase)	Rust (snake_case)	Description
Hard breaks	hardBreaks	hard_breaks	Every newline becomes <br />
Highlight	enableHighlight	enable_highlight	==text== → <mark>
Strikethrough	enableStrikethrough	enable_strikethrough	~~text~~ → <del>
Underline	enableUnderline	enable_underline	++text++ → <u>
Tables	enableTables	enable_tables	Pipe table syntax
Autolink	enableAutolink	enable_autolink	Bare URLs & emails → <a>
Task lists	enableTaskLists	enable_task_lists	- [ ] / - [x] checkboxes

JavaScript / TypeScript

npm install ironmark
# or
pnpm add ironmark

Node.js

WASM is embedded and loaded synchronously — no init() needed:

import { parse } from "ironmark";

const html = parse("# Hello\n\nThis is **fast**.");

AST Output

Use parseToAst() when you need the block-level document structure instead of rendered HTML.

import { parseToAst } from "ironmark";

const astJson = parseToAst("# Hello\n\n- [x] done");
const ast = JSON.parse(astJson);

parseToAst() returns a JSON string for portability across JS runtimes and WASM boundaries.

Browser / Bundler

Call init() once before using parse(). It's idempotent and optionally accepts a custom .wasm URL.

import { init, parse } from "ironmark";

await init();

const html = parse("# Hello\n\nThis is **fast**.");

Vite

import { init, parse } from "ironmark";
import wasmUrl from "ironmark/ironmark.wasm?url";

await init(wasmUrl);

const html = parse("# Hello\n\nThis is **fast**.");

Rust

cargo add ironmark

use ironmark::{parse, ParseOptions};

fn main() {
    // with defaults
    let html = parse("# Hello\n\nThis is **fast**.", &ParseOptions::default());

    // with custom options
    let html = parse("line one\nline two", &ParseOptions {
        hard_breaks: false,
        enable_strikethrough: false,
        ..Default::default()
    });
}

AST Output

parse_to_ast() returns the typed Rust AST (Block) directly:

use ironmark::{Block, ParseOptions, parse_to_ast};

fn main() {
    let ast = parse_to_ast("# Hello", &ParseOptions::default());

    match ast {
        Block::Document { children } => {
            println!("top-level blocks: {}", children.len());
        }
        _ => unreachable!("root node is always Document"),
    }
}

Exported AST types:

• Block
• ListKind
• TableData
• TableAlignment

Benchmarks

Development

This project uses pnpm for package management.

Build from source

pnpm setup:wasm
pnpm build

Command	Description
pnpm setup:wasm	Install prerequisites
pnpm build	Release WASM build
pnpm build:dev	Debug WASM build
pnpm test	Run Rust tests
pnpm check	Format check
pnpm clean	Remove build artifacts

Troubleshooting

wasm32-unknown-unknown target not found or wasm-bindgen not found — run pnpm setup:wasm to install all prerequisites.